比较文本

查找两个文本文件之间的差异

Real-time diff

Unified diff

Collapse lines

Highlight change

Syntax highlighting

工具

Diffchecker Desktop The most secure way to run Diffchecker. Get the Diffchecker Desktop app: your diffs never leave your computer!Get Desktop

Untitled diff

Created 10 years agoDiff never expires

Lines
Total
Removed

Words
Total
Removed

To continue using this feature, upgrade to Diffchecker Pro View Pricing

685 lines

Lines
Total
Added

Words
Total
Added

To continue using this feature, upgrade to Diffchecker Pro View Pricing

686 lines

dark@reco ~/workspace/dotty/tests/pos (fix-838) $ dotc Iter3.scala

parsed:

package dotty1.collections {

package immutable {

import annotation.unchecked.uncheckedVariance

module object Iter2 extends {

<trait> trait Iterator[A] extends IterableOnce[A] {

def hasNext: Boolean

def next: A

def iterator = this

def foreach(f: (A) => Unit): Unit = ???

def map[B](f: (A) => B): Iterator[B] = ???

def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???

def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???

def drop(n: Int): Iterator[A] = ???

def indexWhere(p: (A) => Boolean): Int = {

var i = 0

while (hasNext) do {

if (p(next)) return i

i += 1

}

-1

}

def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???

}

<trait> trait IterableOnce[A] extends {

def iterator: Iterator[A]

def buildIterator: Iterator[A] = iterator

}

<trait> trait FromIterator[C[X] <: Iterable[X]] extends {

def fromIterator[B](it: Iterator[B]): C[B]

}

<trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[

Iterable

] {}

<trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {

def apply(i: Int): AA

def length: Int

}

<trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {

def isEmpty: Boolean

def head: A

def tail: List[A]

def iterator = new ListIterator[A](this)

def fromIterator[B](it: Iterator[B]): List[B] =

it match {

case ListIterator(xs) =>

case _ =>

if (it.hasNext) Cons(it.next, fromIterator(it)) else

Nil.asInstanceOf[List[B]]

}

def apply(i: Int): A = {

require(! isEmpty)

if (i == 0) head else tail.apply(i - 1)

}

def length: Int = if (isEmpty) 0 else 1 + tail.length

}

case class Cons[A](val x: A, val xs: List[A]) extends List[A] {

def isEmpty = false

def head = x

def tail = xs

}

module case object Nil extends List[Nothing] {

def isEmpty = true

def head = ???

def tail = ???

}

class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],

private[this] val initLen: Int

) extends Seq[A] with FromIterator[ArrayBuffer] {

def <init>() = {

<init>(new Array[AnyRef](16), 0)

()

}

def <init>(it: ArrayIterator[A]) = {

<init>(it.elems, it.len)

()

}

private var elems: Array[AnyRef] = initElems

private var len = 0

def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]

override def buildIterator =

new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]

def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =

new ArrayBuffer(ArrayIterator.fromIterator(it))

def apply(i: Int) = elems(i).asInstanceOf[A]

def length = len

}

implicit class IterableTransforms[A, C[X] <: Iterable[X]](

val c: Iterable[A] & FromIterator[C]

) extends AnyVal {

def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))

def flatMap[B](f: (A) => IterableOnce[B]): C[B] =

c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))

def ++[B >: A](xs: IterableOnce[B]): C[B] =

c.fromIterator(c.buildIterator ++ xs.buildIterator)

def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))

def head: A = c.iterator.next

def zip[B](xs: IterableOnce[B]): C[(A, B)] =

c.fromIterator(c.iterator.zip(xs.iterator))

}

implicit class SeqTransforms[SA, C[X] <: Seq[X]](

val c: Seq[SA] & FromIterator[C]

) extends AnyVal {

def reverse: C[SA] = {

val elems = new Array[AnyRef](c.length)

var i = elems.length

val it = c.iterator

while (it.hasNext) do {

i -= 1

elems(i) = it.next.asInstanceOf[AnyRef]

}

val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))

xzz

}

def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)

}

case class ListIterator[A](val xs: List[A]) extends Iterator[A] {

private[this] var current: List[A] = xs

def hasNext = ! current.isEmpty

def next = {

val res = current.head

current = current.tail

res

}

case class ArrayIterator[A](val elems: Array[AnyRef], val len: Int)

extends

Iterator[A] {

import ArrayIterator._

private def elem(i: Int) = elems(i).asInstanceOf[A]

private var cur = 0

def hasNext = cur < len

def next = {

val res = elem(cur)

cur += 1

res

}

override def foreach(f: (A) => Unit): Unit =

for i <- 0 until len do f(elem(i))

override def map[B](f: (A) => B): ArrayIterator[B] = {

var mapped = elems

for i <- 0 until len do {

val x = elem(i)

val y = widen(f(x))

if (widen(x) ne y) {

if (mapped eq elems) mapped = new Array[AnyRef](len)

mapped(i) = y

}

if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else

new ArrayIterator(mapped, len)

}

override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =

flatten(map(_$2 => f(_$2).buildIterator))

override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {

val thatIterator @ ArrayIterator(elems2, len2) =

fromIterator(that.iterator)

if (len == 0) thatIterator else

if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {

val resLen = len + len2

val resElems = new Array[AnyRef](resLen)

Array.copy(elems, 0, resElems, 0, len)

Array.copy(elems2, 0, resElems, len, len2)

new ArrayIterator(resElems, resLen)

}

module object ArrayIterator extends {

private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]

def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =

it match {

case it: ArrayIterator[A] =>

case _ =>

var elems = new Array[AnyRef](32)

var len = 0

def ensureCapacity() = {

while (len > elems.length) do {

val newElems = new Array[AnyRef](elems.length * 2)

Array.copy(elems, 0, newElems, 0, elems.length)

elems = newElems

}

while (it.hasNext) do {

len += 1

ensureCapacity()

elems(len - 1) = widen(it.next)

}

ArrayIterator(elems, len)

}

def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {

var arrayIts = its.map(fromIterator)

var totalLen = 0

arrayIts.foreach(_$3 => totalLen += _$3.len)

val allElems = new Array[AnyRef](totalLen)

var j = 0

arrayIts.foreach({

it => {

Array.copy(it.elems, 0, allElems, j, it.len)

j += it.len

}

})

new ArrayIterator(allElems, totalLen)

}

Expansion: module object Iter2 extends {

<trait> trait Iterator[A] extends IterableOnce[A] {

def hasNext: Boolean

def next: A

def iterator = this

def foreach(f: (A) => Unit): Unit = ???

def map[B](f: (A) => B): Iterator[B] = ???

def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???

def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???

def drop(n: Int): Iterator[A] = ???

def indexWhere(p: (A) => Boolean): Int = {

var i = 0

while (hasNext) do {

if (p(next)) return i

i += 1

}

-1

}

def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???

}

<trait> trait IterableOnce[A] extends {

def iterator: Iterator[A]

def buildIterator: Iterator[A] = iterator

}

<trait> trait FromIterator[C[X] <: Iterable[X]] extends {

def fromIterator[B](it: Iterator[B]): C[B]

}

<trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[Iterable

]

{}

<trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {

def apply(i: Int): AA

def length: Int

}

<trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {

def isEmpty: Boolean

def head: A

def tail: List[A]

def iterator = new ListIterator[A](this)

def fromIterator[B](it: Iterator[B]): List[B] =

it match {

case ListIterator(xs) =>

case _ =>

if (it.hasNext) Cons(it.next, fromIterator(it)) else

Nil.asInstanceOf[List[B]]

}

def apply(i: Int): A = {

require(! isEmpty)

if (i == 0) head else tail.apply(i - 1)

}

def length: Int = if (isEmpty) 0 else 1 + tail.length

}

case class Cons[A](val x: A, val xs: List[A]) extends List[A] {

def isEmpty = false

def head = x

def tail = xs

}

module case object Nil extends List[Nothing] {

def isEmpty = true

def head = ???

def tail = ???

}

class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],

private[this] val initLen: Int

) extends Seq[A] with FromIterator[ArrayBuffer] {

def <init>() = {

<init>(new Array[AnyRef](16), 0)

()

}

def <init>(it: ArrayIterator[A]) = {

<init>(it.elems, it.len)

()

}

private var elems: Array[AnyRef] = initElems

private var len = 0

def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]

override def buildIterator =

new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]

def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =

new ArrayBuffer(ArrayIterator.fromIterator(it))

def apply(i: Int) = elems(i).asInstanceOf[A]

def length = len

}

implicit class IterableTransforms[A, C[X] <: Iterable[X]](

val c: Iterable[A] & FromIterator[C]

) extends AnyVal {

def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))

def flatMap[B](f: (A) => IterableOnce[B]): C[B] =

c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))

def ++[B >: A](xs: IterableOnce[B]): C[B] =

c.fromIterator(c.buildIterator ++ xs.buildIterator)

def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))

def head: A = c.iterator.next

def zip[B](xs: IterableOnce[B]): C[(A, B)] =

c.fromIterator(c.iterator.zip(xs.iterator))

}

implicit class SeqTransforms[SA, C[X] <: Seq[X]](

val c: Seq[SA] & FromIterator[C]

) extends AnyVal {

def reverse: C[SA] = {

val elems = new Array[AnyRef](c.length)

var i = elems.length

val it = c.iterator

while (it.hasNext) do {

i -= 1

elems(i) = it.next.asInstanceOf[AnyRef]

}

val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))

xzz

}

def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)

}

case class ListIterator[A](val xs: List[A]) extends Iterator[A] {

private[this] var current: List[A] = xs

def hasNext = ! current.isEmpty

def next = {

val res = current.head

current = current.tail

res

}

case class ArrayIterator[A](val elems: Array[AnyRef], val len: Int) extends

Iterator

[A] {

import ArrayIterator._

private def elem(i: Int) = elems(i).asInstanceOf[A]

private var cur = 0

def hasNext = cur < len

def next = {

val res = elem(cur)

cur += 1

res

}

override def foreach(f: (A) => Unit): Unit =

for i <- 0 until len do f(elem(i))

override def map[B](f: (A) => B): ArrayIterator[B] = {

var mapped = elems

for i <- 0 until len do {

val x = elem(i)

val y = widen(f(x))

if (widen(x) ne y) {

if (mapped eq elems) mapped = new Array[AnyRef](len)

mapped(i) = y

}

if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else

new ArrayIterator(mapped, len)

}

override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =

flatten(map(_$2 => f(_$2).buildIterator))

override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {

val thatIterator @ ArrayIterator(elems2, len2) =

fromIterator(that.iterator)

if (len == 0) thatIterator else

if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {

val resLen = len + len2

val resElems = new Array[AnyRef](resLen)

Array.copy(elems, 0, resElems, 0, len)

Array.copy(elems2, 0, resElems, len, len2)

new ArrayIterator(resElems, resLen)

}

module object ArrayIterator extends {

private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]

def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =

it match {

case it: ArrayIterator[A] =>

case _ =>

var elems = new Array[AnyRef](32)

var len = 0

def ensureCapacity() = {

while (len > elems.length) do {

val newElems = new Array[AnyRef](elems.length * 2)

Array.copy(elems, 0, newElems, 0, elems.length)

elems = newElems

}

while (it.hasNext) do {

len += 1

ensureCapacity()

elems(len - 1) = widen(it.next)

}

ArrayIterator(elems, len)

}

def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {

var arrayIts = its.map(fromIterator)

var totalLen = 0

arrayIts.foreach(_$3 => totalLen += _$3.len)

val allElems = new Array[AnyRef](totalLen)

var j = 0

arrayIts.foreach({

it => {

Array.copy(it.elems, 0, allElems, j, it.len)

j += it.len

}

})

new ArrayIterator(allElems, totalLen)

}

} expands to Thicket {

final lazy module val Iter2: Iter2$ = new Iter2$()

final module class Iter2$() extends { this: Iter2.type =>

<trait> trait Iterator[A] extends IterableOnce[A] {

def hasNext: Boolean

def next: A

def iterator = this

def foreach(f: (A) => Unit): Unit = ???

def map[B](f: (A) => B): Iterator[B] = ???

def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???

def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???

def drop(n: Int): Iterator[A] = ???

def indexWhere(p: (A) => Boolean): Int = {

var i = 0

while (hasNext) do {

if (p(next)) return i

i += 1

}

-1

}

def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???

}

<trait> trait IterableOnce[A] extends {

def iterator: Iterator[A]

def buildIterator: Iterator[A] = iterator

}

<trait> trait FromIterator[C[X] <: Iterable[X]] extends {

def fromIterator[B](it: Iterator[B]): C[B]

}

<trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[

Iterable

] {}

<trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {

def apply(i: Int): AA

def length: Int

}

<trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {

def isEmpty: Boolean

def head: A

def tail: List[A]

def iterator = new ListIterator[A](this)

def fromIterator[B](it: Iterator[B]): List[B] =

it match {

case ListIterator(xs) =>

case _ =>

if (it.hasNext) Cons(it.next, fromIterator(it)) else

Nil.asInstanceOf[List[B]]

}

def apply(i: Int): A = {

require(! isEmpty)

if (i == 0) head else tail.apply(i - 1)

}

def length: Int = if (isEmpty) 0 else 1 + tail.length

}

case class Cons[A](val x: A, val xs: List[A]) extends List[A] {

def isEmpty = false

def head = x

def tail = xs

}

module case object Nil extends List[Nothing] {

def isEmpty = true

def head = ???

def tail = ???

}

class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],

private[this] val initLen: Int

) extends Seq[A] with FromIterator[ArrayBuffer] {

def <init>() = {

<init>(new Array[AnyRef](16), 0)

()

}

def <init>(it: ArrayIterator[A]) = {

<init>(it.elems, it.len)

()

}

private var elems: Array[AnyRef] = initElems

private var len = 0

def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]

override def buildIterator =

new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]

def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =

new ArrayBuffer(ArrayIterator.fromIterator(it))

def apply(i: Int) = elems(i).asInstanceOf[A]

def length = len

}

implicit class IterableTransforms[A, C[X] <: Iterable[X]](

val c: Iterable[A] & FromIterator[C]

) extends AnyVal {

def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))

def flatMap[B](f: (A) => IterableOnce[B]): C[B] =

c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))

def ++[B >: A](xs: IterableOnce[B]): C[B] =

c.fromIterator(c.buildIterator ++ xs.buildIterator)

def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))

def head: A = c.iterator.next

def zip[B](xs: IterableOnce[B]): C[(A, B)] =

c.fromIterator(c.iterator.zip(xs.iterator))

}

implicit class SeqTransforms[SA, C[X] <: Seq[X]](

val c: Seq[SA] & FromIterator[C]

) extends AnyVal {

def reverse: C[SA] = {

val elems = new Array[AnyRef](c.length)

var i = elems.length

val it = c.iterator

while (it.hasNext) do {

i -= 1

elems(i) = it.next.asInstanceOf[AnyRef]

}

val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))

xzz

}

def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)

}

case class ListIterator[A](val xs: List[A]) extends Iterator[A] {

private[this] var current: List[A] = xs

def hasNext = ! current.isEmpty

def next = {

val res = current.head

current = current.tail

res

}

case class ArrayIterator[A](val elems: Array[AnyRef], val len: Int) extends

Iterator

[A] {

import ArrayIterator._

private def elem(i: Int) = elems(i).asInstanceOf[A]

private var cur = 0

def hasNext = cur < len

def next = {

val res = elem(cur)

cur += 1

res

}

override def foreach(f: (A) => Unit): Unit =

for i <- 0 until len do f(elem(i))

override def map[B](f: (A) => B): ArrayIterator[B] = {

var mapped = elems

for i <- 0 until len do {

val x = elem(i)

val y = widen(f(x))

if (widen(x) ne y) {

if (mapped eq elems) mapped = new Array[AnyRef](len)

mapped(i) = y

}

if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else

new ArrayIterator(mapped, len)

}

override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =

flatten(map(_$2 => f(_$2).buildIterator))

override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {

val thatIterator @ ArrayIterator(elems2, len2) =

fromIterator(that.iterator)

if (len == 0) thatIterator else

if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {

val resLen = len + len2

val resElems = new Array[AnyRef](resLen)

Array.copy(elems, 0, resElems, 0, len)

Array.copy(elems2, 0, resElems, len, len2)

new ArrayIterator(resElems, resLen)

}

module object ArrayIterator extends {

private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]

def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =

it match {

case it: ArrayIterator[A] =>

case _ =>

var elems = new Array[AnyRef](32)

var len = 0

def ensureCapacity() = {

while (len > elems.length) do {

val newElems = new Array[AnyRef](elems.length * 2)

Array.copy(elems, 0, newElems, 0, elems.length)

elems = newElems

}

while (it.hasNext) do {

len += 1

ensureCapacity()

elems(len - 1) = widen(it.next)

}

ArrayIterator(elems, len)

}

def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {

var arrayIts = its.map(fromIterator)

var totalLen = 0

arrayIts.foreach(_$3 => totalLen += _$3.len)

val allElems = new Array[AnyRef](totalLen)

var j = 0

arrayIts.foreach({

it => {

Array.copy(it.elems, 0, allElems, j, it.len)

j += it.len

}

})

new ArrayIterator(allElems, totalLen)

}

creating symbol for import annotation.unchecked.uncheckedVariance in Mode(ImplicitsEnabled)

creating symbol for final lazy module val Iter2: Iter2$ = new Iter2$() in Mode(ImplicitsEnabled)

entered: module Iter2 in module class immutable and Scopes(class Iter2$ArrayBuffer, module Iter2$ArrayBuffer, module class Iter2$ArrayBuffer$, class Iter2$ArrayIterator, module Iter2$ArrayIterator, module class Iter2$ArrayIterator$, class Iter2$Cons, module Iter2$Cons, module class Iter2$Cons$, class Iter2$FromIterator, module Iter2$FromIterator, module class Iter2$FromIterator$, class Iter2$Iterable, module Iter2$Iterable, module class Iter2$Iterable$, class Iter2$IterableOnce, module Iter2$IterableOnce, module class Iter2$IterableOnce$, class Iter2$IterableTransforms, module Iter2$IterableTransforms, module class Iter2$IterableTransforms$, class Iter2$Iterator, module Iter2$Iterator, module class Iter2$Iterator$, class Iter2$List, module Iter2$List, module class Iter2$List$, class Iter2$ListIterator, module Iter2$ListIterator, module class Iter2$ListIterator$, class Iter2$Nil, module Iter2$Nil, module class Iter2$Nil$, class Iter2$Seq, module Iter2$Seq, module class Iter2$Seq$, class Iter2$SeqTransforms, module Iter2$SeqTransforms, module class Iter2$SeqTransforms$, class Iter2$View, module Iter2$View, module class Iter2$View$, class Iter2, module Iter2, module class Iter2$)

creating symbol for final module class Iter2$() extends { this: Iter2.type =>

<trait> trait Iterator[A] extends IterableOnce[A] {

def hasNext: Boolean

def next: A

def iterator = this

def foreach(f: (A) => Unit): Unit = ???

def map[B](f: (A) => B): Iterator[B] = ???

def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???

def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???

def drop(n: Int): Iterator[A] = ???

def indexWhere(p: (A) => Boolean): Int = {

var i = 0

while (hasNext) do {

if (p(next)) return i

i += 1

}

-1

}

def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???

}

<trait> trait IterableOnce[A] extends {

def iterator: Iterator[A]

def buildIterator: Iterator[A] = iterator

}

<trait> trait FromIterator[C[X] <: Iterable[X]] extends {

def fromIterator[B](it: Iterator[B]): C[B]

}

<trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[Iterable

]

{}

<trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {

def apply(i: Int): AA

def length: Int

}

<trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {

def isEmpty: Boolean

def head: A

def tail: List[A]

def iterator = new ListIterator[A](this)

def fromIterator[B](it: Iterator[B]): List[B] =

it match {

case ListIterator(xs) =>

case _ =>

if (it.hasNext) Cons(it.next, fromIterator(it)) else

Nil.asInstanceOf[List[B]]

}

def apply(i: Int): A = {

require(! isEmpty)

if (i == 0) head else tail.apply(i - 1)

}

def length: Int = if (isEmpty) 0 else 1 + tail.length

}

case class Cons[A](val x: A, val xs: List[A]) extends List[A] {

def isEmpty = false

def head = x

def tail = xs

}

module case object Nil extends List[Nothing] {

def isEmpty = true

def head = ???

def tail = ???

}

class ArrayBuffer[A] private(private[this] val initEle

class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],

private[this] val initLen: Int

) extends S

已保存差异

原始文本

打开文件

dark@reco ~/workspace/dotty/tests/pos (fix-838) $ dotc Iter3.scala
parsed:
package dotty1.collections {
  package immutable {
    import annotation.unchecked.uncheckedVariance
    module object Iter2 extends {
      <trait> trait Iterator[A] extends IterableOnce[A] {
        def hasNext: Boolean
        def next: A
        def iterator = this
        def foreach(f: (A) => Unit): Unit = ???
        def map[B](f: (A) => B): Iterator[B] = ???
        def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
        def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
        def drop(n: Int): Iterator[A] = ???
        def indexWhere(p: (A) => Boolean): Int = {
          var i = 0
          while (hasNext) do {
            if (p(next)) return i
            i += 1
          }
          -1
        }
        def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
      }
      <trait> trait IterableOnce[A] extends {
        def iterator: Iterator[A]
        def buildIterator: Iterator[A] = iterator
      }
      <trait> trait FromIterator[C[X] <: Iterable[X]] extends {
        def fromIterator[B](it: Iterator[B]): C[B]
      }
      <trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[
        Iterable
      ] {}
      <trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {
        def apply(i: Int): AA
        def length: Int
      }
      <trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {
        def isEmpty: Boolean
        def head: A
        def tail: List[A]
        def iterator = new ListIterator[A](this)
        def fromIterator[B](it: Iterator[B]): List[B] =
          it match {
            case ListIterator(xs) =>
              xs
            case _ =>
              if (it.hasNext) Cons(it.next, fromIterator(it)) else
                Nil.asInstanceOf[List[B]]
          }
        def apply(i: Int): A = {
          require(! isEmpty)
          if (i == 0) head else tail.apply(i - 1)
        }
        def length: Int = if (isEmpty) 0 else 1 + tail.length
      }
      case class Cons[A](val x: A, val xs: List[A]) extends List[A] {
        def isEmpty = false
        def head = x
        def tail = xs
      }
      module case object Nil extends List[Nothing] {
        def isEmpty = true
        def head = ???
        def tail = ???
      }
      class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],
        private[this] val initLen: Int
      ) extends Seq[A] with FromIterator[ArrayBuffer] {
        def <init>() = {
          <init>(new Array[AnyRef](16), 0)
          ()
        }
        def <init>(it: ArrayIterator[A]) = {
          <init>(it.elems, it.len)
          ()
        }
        private var elems: Array[AnyRef] = initElems
        private var len = 0
        def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
        override def buildIterator =
          new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
        def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
          new ArrayBuffer(ArrayIterator.fromIterator(it))
        def apply(i: Int) = elems(i).asInstanceOf[A]
        def length = len
      }
      implicit class IterableTransforms[A, C[X] <: Iterable[X]](
        val c: Iterable[A] & FromIterator[C]
      ) extends AnyVal {
        def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
        def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
          c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
        def ++[B >: A](xs: IterableOnce[B]): C[B] =
          c.fromIterator(c.buildIterator ++ xs.buildIterator)
        def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
        def head: A = c.iterator.next
        def zip[B](xs: IterableOnce[B]): C[(A, B)] =
          c.fromIterator(c.iterator.zip(xs.iterator))
      }
      implicit class SeqTransforms[SA, C[X] <: Seq[X]](
        val c: Seq[SA] & FromIterator[C]
      ) extends AnyVal {
        def reverse: C[SA] = {
          val elems = new Array[AnyRef](c.length)
          var i = elems.length
          val it = c.iterator
          while (it.hasNext) do {
            i -= 1
            elems(i) = it.next.asInstanceOf[AnyRef]
          }
          val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
          xzz
        }
        def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
      }
      case class ListIterator[A](val xs: List[A]) extends Iterator[A] {
        private[this] var current: List[A] = xs
        def hasNext = ! current.isEmpty
        def next = {
          val res = current.head
          current = current.tail
          res
        }
      }
      case class ArrayIterator[A](val elems: Array[AnyRef], val len: Int)
         extends
       Iterator[A] {
        import ArrayIterator._
        private def elem(i: Int) = elems(i).asInstanceOf[A]
        private var cur = 0
        def hasNext = cur < len
        def next = {
          val res = elem(cur)
          cur += 1
          res
        }
        override def foreach(f: (A) => Unit): Unit =
          for i <- 0 until len do f(elem(i))
        override def map[B](f: (A) => B): ArrayIterator[B] = {
          var mapped = elems
          for i <- 0 until len do {
            val x = elem(i)
            val y = widen(f(x))
            if (widen(x) ne y) {
              if (mapped eq elems) mapped = new Array[AnyRef](len)
              mapped(i) = y
            }
          }
          if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
            new ArrayIterator(mapped, len)
        }
        override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
          flatten(map(_$2 => f(_$2).buildIterator))
        override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
          val thatIterator @ ArrayIterator(elems2, len2) =
            fromIterator(that.iterator)
          if (len == 0) thatIterator else
            if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
              val resLen = len + len2
              val resElems = new Array[AnyRef](resLen)
              Array.copy(elems, 0, resElems, 0, len)
              Array.copy(elems2, 0, resElems, len, len2)
              new ArrayIterator(resElems, resLen)
            }
        }
      }
      module object ArrayIterator extends {
        private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]
        def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =
          it match {
            case it: ArrayIterator[A] =>
              it
            case _ =>
              var elems = new Array[AnyRef](32)
              var len = 0
              def ensureCapacity() = {
                while (len > elems.length) do {
                  val newElems = new Array[AnyRef](elems.length * 2)
                  Array.copy(elems, 0, newElems, 0, elems.length)
                  elems = newElems
                }
              }
              while (it.hasNext) do {
                len += 1
                ensureCapacity()
                elems(len - 1) = widen(it.next)
              }
              ArrayIterator(elems, len)
          }
        def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {
          var arrayIts = its.map(fromIterator)
          var totalLen = 0
          arrayIts.foreach(_$3 => totalLen += _$3.len)
          val allElems = new Array[AnyRef](totalLen)
          var j = 0
          arrayIts.foreach({
            it => {
              Array.copy(it.elems, 0, allElems, j, it.len)
              j += it.len
            }
          })
          new ArrayIterator(allElems, totalLen)
        }
      }
    }
  }
}
Expansion: module object Iter2 extends {
  <trait> trait Iterator[A] extends IterableOnce[A] {
    def hasNext: Boolean
    def next: A
    def iterator = this
    def foreach(f: (A) => Unit): Unit = ???
    def map[B](f: (A) => B): Iterator[B] = ???
    def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
    def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
    def drop(n: Int): Iterator[A] = ???
    def indexWhere(p: (A) => Boolean): Int = {
      var i = 0
      while (hasNext) do {
        if (p(next)) return i
        i += 1
      }
      -1
    }
    def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
  }
  <trait> trait IterableOnce[A] extends {
    def iterator: Iterator[A]
    def buildIterator: Iterator[A] = iterator
  }
  <trait> trait FromIterator[C[X] <: Iterable[X]] extends {
    def fromIterator[B](it: Iterator[B]): C[B]
  }
  <trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[Iterable
    ]
   {}
  <trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {
    def apply(i: Int): AA
    def length: Int
  }
  <trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {
    def isEmpty: Boolean
    def head: A
    def tail: List[A]
    def iterator = new ListIterator[A](this)
    def fromIterator[B](it: Iterator[B]): List[B] =
      it match {
        case ListIterator(xs) =>
          xs
        case _ =>
          if (it.hasNext) Cons(it.next, fromIterator(it)) else
            Nil.asInstanceOf[List[B]]
      }
    def apply(i: Int): A = {
      require(! isEmpty)
      if (i == 0) head else tail.apply(i - 1)
    }
    def length: Int = if (isEmpty) 0 else 1 + tail.length
  }
  case class Cons[A](val x: A, val xs: List[A]) extends List[A] {
    def isEmpty = false
    def head = x
    def tail = xs
  }
  module case object Nil extends List[Nothing] {
    def isEmpty = true
    def head = ???
    def tail = ???
  }
  class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],
    private[this] val initLen: Int
  ) extends Seq[A] with FromIterator[ArrayBuffer] {
    def <init>() = {
      <init>(new Array[AnyRef](16), 0)
      ()
    }
    def <init>(it: ArrayIterator[A]) = {
      <init>(it.elems, it.len)
      ()
    }
    private var elems: Array[AnyRef] = initElems
    private var len = 0
    def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
    override def buildIterator =
      new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
    def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
      new ArrayBuffer(ArrayIterator.fromIterator(it))
    def apply(i: Int) = elems(i).asInstanceOf[A]
    def length = len
  }
  implicit class IterableTransforms[A, C[X] <: Iterable[X]](
    val c: Iterable[A] & FromIterator[C]
  ) extends AnyVal {
    def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
    def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
      c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
    def ++[B >: A](xs: IterableOnce[B]): C[B] =
      c.fromIterator(c.buildIterator ++ xs.buildIterator)
    def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
    def head: A = c.iterator.next
    def zip[B](xs: IterableOnce[B]): C[(A, B)] =
      c.fromIterator(c.iterator.zip(xs.iterator))
  }
  implicit class SeqTransforms[SA, C[X] <: Seq[X]](
    val c: Seq[SA] & FromIterator[C]
  ) extends AnyVal {
    def reverse: C[SA] = {
      val elems = new Array[AnyRef](c.length)
      var i = elems.length
      val it = c.iterator
      while (it.hasNext) do {
        i -= 1
        elems(i) = it.next.asInstanceOf[AnyRef]
      }
      val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
      xzz
    }
    def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
  }
  case class ListIterator[A](val xs: List[A]) extends Iterator[A] {
    private[this] var current: List[A] = xs
    def hasNext = ! current.isEmpty
    def next = {
      val res = current.head
      current = current.tail
      res
    }
  }
  case class ArrayIterator[A](val elems: Array[AnyRef], val len: Int) extends
    Iterator
  [A] {
    import ArrayIterator._
    private def elem(i: Int) = elems(i).asInstanceOf[A]
    private var cur = 0
    def hasNext = cur < len
    def next = {
      val res = elem(cur)
      cur += 1
      res
    }
    override def foreach(f: (A) => Unit): Unit =
      for i <- 0 until len do f(elem(i))
    override def map[B](f: (A) => B): ArrayIterator[B] = {
      var mapped = elems
      for i <- 0 until len do {
        val x = elem(i)
        val y = widen(f(x))
        if (widen(x) ne y) {
          if (mapped eq elems) mapped = new Array[AnyRef](len)
          mapped(i) = y
        }
      }
      if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
        new ArrayIterator(mapped, len)
    }
    override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
      flatten(map(_$2 => f(_$2).buildIterator))
    override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
      val thatIterator @ ArrayIterator(elems2, len2) =
        fromIterator(that.iterator)
      if (len == 0) thatIterator else
        if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
          val resLen = len + len2
          val resElems = new Array[AnyRef](resLen)
          Array.copy(elems, 0, resElems, 0, len)
          Array.copy(elems2, 0, resElems, len, len2)
          new ArrayIterator(resElems, resLen)
        }
    }
  }
  module object ArrayIterator extends {
    private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]
    def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =
      it match {
        case it: ArrayIterator[A] =>
          it
        case _ =>
          var elems = new Array[AnyRef](32)
          var len = 0
          def ensureCapacity() = {
            while (len > elems.length) do {
              val newElems = new Array[AnyRef](elems.length * 2)
              Array.copy(elems, 0, newElems, 0, elems.length)
              elems = newElems
            }
          }
          while (it.hasNext) do {
            len += 1
            ensureCapacity()
            elems(len - 1) = widen(it.next)
          }
          ArrayIterator(elems, len)
      }
    def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {
      var arrayIts = its.map(fromIterator)
      var totalLen = 0
      arrayIts.foreach(_$3 => totalLen += _$3.len)
      val allElems = new Array[AnyRef](totalLen)
      var j = 0
      arrayIts.foreach({
        it => {
          Array.copy(it.elems, 0, allElems, j, it.len)
          j += it.len
        }
      })
      new ArrayIterator(allElems, totalLen)
    }
  }
} expands to Thicket {
  final lazy module val Iter2: Iter2$ = new Iter2$()
  final module class Iter2$() extends { this: Iter2.type =>
    <trait> trait Iterator[A] extends IterableOnce[A] {
      def hasNext: Boolean
      def next: A
      def iterator = this
      def foreach(f: (A) => Unit): Unit = ???
      def map[B](f: (A) => B): Iterator[B] = ???
      def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
      def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
      def drop(n: Int): Iterator[A] = ???
      def indexWhere(p: (A) => Boolean): Int = {
        var i = 0
        while (hasNext) do {
          if (p(next)) return i
          i += 1
        }
        -1
      }
      def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
    }
    <trait> trait IterableOnce[A] extends {
      def iterator: Iterator[A]
      def buildIterator: Iterator[A] = iterator
    }
    <trait> trait FromIterator[C[X] <: Iterable[X]] extends {
      def fromIterator[B](it: Iterator[B]): C[B]
    }
    <trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[
      Iterable
    ] {}
    <trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {
      def apply(i: Int): AA
      def length: Int
    }
    <trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {
      def isEmpty: Boolean
      def head: A
      def tail: List[A]
      def iterator = new ListIterator[A](this)
      def fromIterator[B](it: Iterator[B]): List[B] =
        it match {
          case ListIterator(xs) =>
            xs
          case _ =>
            if (it.hasNext) Cons(it.next, fromIterator(it)) else
              Nil.asInstanceOf[List[B]]
        }
      def apply(i: Int): A = {
        require(! isEmpty)
        if (i == 0) head else tail.apply(i - 1)
      }
      def length: Int = if (isEmpty) 0 else 1 + tail.length
    }
    case class Cons[A](val x: A, val xs: List[A]) extends List[A] {
      def isEmpty = false
      def head = x
      def tail = xs
    }
    module case object Nil extends List[Nothing] {
      def isEmpty = true
      def head = ???
      def tail = ???
    }
    class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],
      private[this] val initLen: Int
    ) extends Seq[A] with FromIterator[ArrayBuffer] {
      def <init>() = {
        <init>(new Array[AnyRef](16), 0)
        ()
      }
      def <init>(it: ArrayIterator[A]) = {
        <init>(it.elems, it.len)
        ()
      }
      private var elems: Array[AnyRef] = initElems
      private var len = 0
      def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
      override def buildIterator =
        new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
      def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
        new ArrayBuffer(ArrayIterator.fromIterator(it))
      def apply(i: Int) = elems(i).asInstanceOf[A]
      def length = len
    }
    implicit class IterableTransforms[A, C[X] <: Iterable[X]](
      val c: Iterable[A] & FromIterator[C]
    ) extends AnyVal {
      def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
      def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
        c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
      def ++[B >: A](xs: IterableOnce[B]): C[B] =
        c.fromIterator(c.buildIterator ++ xs.buildIterator)
      def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
      def head: A = c.iterator.next
      def zip[B](xs: IterableOnce[B]): C[(A, B)] =
        c.fromIterator(c.iterator.zip(xs.iterator))
    }
    implicit class SeqTransforms[SA, C[X] <: Seq[X]](
      val c: Seq[SA] & FromIterator[C]
    ) extends AnyVal {
      def reverse: C[SA] = {
        val elems = new Array[AnyRef](c.length)
        var i = elems.length
        val it = c.iterator
        while (it.hasNext) do {
          i -= 1
          elems(i) = it.next.asInstanceOf[AnyRef]
        }
        val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
        xzz
      }
      def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
    }
    case class ListIterator[A](val xs: List[A]) extends Iterator[A] {
      private[this] var current: List[A] = xs
      def hasNext = ! current.isEmpty
      def next = {
        val res = current.head
        current = current.tail
        res
      }
    }
    case class ArrayIterator[A](val elems: Array[AnyRef], val len: Int) extends
      Iterator
    [A] {
      import ArrayIterator._
      private def elem(i: Int) = elems(i).asInstanceOf[A]
      private var cur = 0
      def hasNext = cur < len
      def next = {
        val res = elem(cur)
        cur += 1
        res
      }
      override def foreach(f: (A) => Unit): Unit =
        for i <- 0 until len do f(elem(i))
      override def map[B](f: (A) => B): ArrayIterator[B] = {
        var mapped = elems
        for i <- 0 until len do {
          val x = elem(i)
          val y = widen(f(x))
          if (widen(x) ne y) {
            if (mapped eq elems) mapped = new Array[AnyRef](len)
            mapped(i) = y
          }
        }
        if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
          new ArrayIterator(mapped, len)
      }
      override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
        flatten(map(_$2 => f(_$2).buildIterator))
      override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
        val thatIterator @ ArrayIterator(elems2, len2) =
          fromIterator(that.iterator)
        if (len == 0) thatIterator else
          if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
            val resLen = len + len2
            val resElems = new Array[AnyRef](resLen)
            Array.copy(elems, 0, resElems, 0, len)
            Array.copy(elems2, 0, resElems, len, len2)
            new ArrayIterator(resElems, resLen)
          }
      }
    }
    module object ArrayIterator extends {
      private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]
      def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =
        it match {
          case it: ArrayIterator[A] =>
            it
          case _ =>
            var elems = new Array[AnyRef](32)
            var len = 0
            def ensureCapacity() = {
              while (len > elems.length) do {
                val newElems = new Array[AnyRef](elems.length * 2)
                Array.copy(elems, 0, newElems, 0, elems.length)
                elems = newElems
              }
            }
            while (it.hasNext) do {
              len += 1
              ensureCapacity()
              elems(len - 1) = widen(it.next)
            }
            ArrayIterator(elems, len)
        }
      def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {
        var arrayIts = its.map(fromIterator)
        var totalLen = 0
        arrayIts.foreach(_$3 => totalLen += _$3.len)
        val allElems = new Array[AnyRef](totalLen)
        var j = 0
        arrayIts.foreach({
          it => {
            Array.copy(it.elems, 0, allElems, j, it.len)
            j += it.len
          }
        })
        new ArrayIterator(allElems, totalLen)
      }
    }
  }
 }
creating symbol for import annotation.unchecked.uncheckedVariance in Mode(ImplicitsEnabled)
creating symbol for final lazy module val Iter2: Iter2$ = new Iter2$() in Mode(ImplicitsEnabled)
entered: module Iter2 in module class immutable and Scopes(class Iter2$ArrayBuffer, module Iter2$ArrayBuffer, module class Iter2$ArrayBuffer$, class Iter2$ArrayIterator, module Iter2$ArrayIterator, module class Iter2$ArrayIterator$, class Iter2$Cons, module Iter2$Cons, module class Iter2$Cons$, class Iter2$FromIterator, module Iter2$FromIterator, module class Iter2$FromIterator$, class Iter2$Iterable, module Iter2$Iterable, module class Iter2$Iterable$, class Iter2$IterableOnce, module Iter2$IterableOnce, module class Iter2$IterableOnce$, class Iter2$IterableTransforms, module Iter2$IterableTransforms, module class Iter2$IterableTransforms$, class Iter2$Iterator, module Iter2$Iterator, module class Iter2$Iterator$, class Iter2$List, module Iter2$List, module class Iter2$List$, class Iter2$ListIterator, module Iter2$ListIterator, module class Iter2$ListIterator$, class Iter2$Nil, module Iter2$Nil, module class Iter2$Nil$, class Iter2$Seq, module Iter2$Seq, module class Iter2$Seq$, class Iter2$SeqTransforms, module Iter2$SeqTransforms, module class Iter2$SeqTransforms$, class Iter2$View, module Iter2$View, module class Iter2$View$, class Iter2, module Iter2, module class Iter2$)
creating symbol for final module class Iter2$() extends { this: Iter2.type =>
  <trait> trait Iterator[A] extends IterableOnce[A] {
    def hasNext: Boolean
    def next: A
    def iterator = this
    def foreach(f: (A) => Unit): Unit = ???
    def map[B](f: (A) => B): Iterator[B] = ???
    def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
    def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
    def drop(n: Int): Iterator[A] = ???
    def indexWhere(p: (A) => Boolean): Int = {
      var i = 0
      while (hasNext) do {
        if (p(next)) return i
        i += 1
      }
      -1
    }
    def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
  }
  <trait> trait IterableOnce[A] extends {
    def iterator: Iterator[A]
    def buildIterator: Iterator[A] = iterator
  }
  <trait> trait FromIterator[C[X] <: Iterable[X]] extends {
    def fromIterator[B](it: Iterator[B]): C[B]
  }
  <trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[Iterable
    ]
   {}
  <trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {
    def apply(i: Int): AA
    def length: Int
  }
  <trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {
    def isEmpty: Boolean
    def head: A
    def tail: List[A]
    def iterator = new ListIterator[A](this)
    def fromIterator[B](it: Iterator[B]): List[B] =
      it match {
        case ListIterator(xs) =>
          xs
        case _ =>
          if (it.hasNext) Cons(it.next, fromIterator(it)) else
            Nil.asInstanceOf[List[B]]
      }
    def apply(i: Int): A = {
      require(! isEmpty)
      if (i == 0) head else tail.apply(i - 1)
    }
    def length: Int = if (isEmpty) 0 else 1 + tail.length
  }
  case class Cons[A](val x: A, val xs: List[A]) extends List[A] {
    def isEmpty = false
    def head = x
    def tail = xs
  }
  module case object Nil extends List[Nothing] {
    def isEmpty = true
    def head = ???
    def tail = ???
  }
  class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],
    private[this] val initLen: Int
  ) extends Seq[A] with FromIterator[ArrayBuffer] {
    def <init>() = {
      <init>(new Array[AnyRef](16), 0)
      ()
    }
    def <init>(it: ArrayIterator[A]) = {
      <init>(it.elems, it.len)
      ()
    }
    private var elems: Array[AnyRef] = initElems
    private var len = 0
    def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
    override def buildIterator =
      new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
    def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
      new ArrayBuffer(ArrayIterator.fromIterator(it))
    def apply(i: Int) = elems(i).asInstanceOf[A]
    def length = len
  }
  implicit class IterableTransforms[A, C[X] <: Iterable[X]](
    val c: Iterable[A] & FromIterator[C]
  ) extends AnyVal {
    def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
    def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
      c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
    def ++[B >: A](xs: IterableOnce[B]): C[B] =
      c.fromIterator(c.buildIterator ++ xs.buildIterator)
    def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
    def head: A = c.iterator.next
    def zip[B](xs: IterableOnce[B]): C[(A, B)] =
      c.fromIterator(c.iterator.zip(xs.iterator))
  }
  implicit class SeqTransforms[SA, C[X] <: Seq[X]](
    val c: Seq[SA] & FromIterator[C]
  ) extends AnyVal {
    def reverse: C[SA] = {
      val elems = new Array[AnyRef](c.length)
      var i = elems.length
      val it = c.iterator
      while (it.hasNext) do {
        i -= 1
        elems(i) = it.next.asInstanceOf[AnyRef]
      }
      val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
      xzz
    }
    def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
  }
  case class ListIterator[A](val xs: List[A]) extends Iterator[A] {
    private[this] var current: List[A] = xs
    def hasNext = ! current.isEmpty
    def next = {
      val res = current.head
      current = current.tail
      res
    }
  }
  case class ArrayIterator[A](val elems: Array[AnyRef], val len: Int) extends
    Iterator
  [A] {
    import ArrayIterator._
    private def elem(i: Int) = elems(i).asInstanceOf[A]
    private var cur = 0
    def hasNext = cur < len
    def next = {
      val res = elem(cur)
      cur += 1
      res
    }
    override def foreach(f: (A) => Unit): Unit =
      for i <- 0 until len do f(elem(i))
    override def map[B](f: (A) => B): ArrayIterator[B] = {
      var mapped = elems
      for i <- 0 until len do {
        val x = elem(i)
        val y = widen(f(x))
        if (widen(x) ne y) {
          if (mapped eq elems) mapped = new Array[AnyRef](len)
          mapped(i) = y
        }
      }
      if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
        new ArrayIterator(mapped, len)
    }
    override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
      flatten(map(_$2 => f(_$2).buildIterator))
    override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
      val thatIterator @ ArrayIterator(elems2, len2) =
        fromIterator(that.iterator)
      if (len == 0) thatIterator else
        if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
          val resLen = len + len2
          val resElems = new Array[AnyRef](resLen)
          Array.copy(elems, 0, resElems, 0, len)
          Array.copy(elems2, 0, resElems, len, len2)
          new ArrayIterator(resElems, resLen)
        }
    }
  }
  module object ArrayIterator extends {
    private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]
    def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =
      it match {
        case it: ArrayIterator[A] =>
          it
        case _ =>
          var elems = new Array[AnyRef](32)
          var len = 0
          def ensureCapacity() = {
            while (len > elems.length) do {
              val newElems = new Array[AnyRef](elems.length * 2)
              Array.copy(elems, 0, newElems, 0, elems.length)
              elems = newElems
            }
          }
          while (it.hasNext) do {
            len += 1
            ensureCapacity()
            elems(len - 1) = widen(it.next)
          }
          ArrayIterator(elems, len)
      }
    def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {
      var arrayIts = its.map(fromIterator)
      var totalLen = 0
      arrayIts.foreach(_$3 => totalLen += _$3.len)
      val allElems = new Array[AnyRef](totalLen)
      var j = 0
      arrayIts.foreach({
        it => {
          Array.copy(it.elems, 0, allElems, j, it.len)
          j += it.len
        }
      })
      new ArrayIterator(allElems, totalLen)
    }
  }
} in Mode(ImplicitsEnabled)
entered: module class Iter2$ in module class immutable and Scopes(class Iter2$ArrayBuffer, module Iter2$ArrayBuffer, module class Iter2$ArrayBuffer$, class Iter2$ArrayIterator, module Iter2$ArrayIterator, module class Iter2$ArrayIterator$, class Iter2$Cons, module Iter2$Cons, module class Iter2$Cons$, class Iter2$FromIterator, module Iter2$FromIterator, module class Iter2$FromIterator$, class Iter2$Iterable, module Iter2$Iterable, module class Iter2$Iterable$, class Iter2$IterableOnce, module Iter2$IterableOnce, module class Iter2$IterableOnce$, class Iter2$IterableTransforms, module Iter2$IterableTransforms, module class Iter2$IterableTransforms$, class Iter2$Iterator, module Iter2$Iterator, module class Iter2$Iterator$, class Iter2$List, module Iter2$List, module class Iter2$List$, class Iter2$ListIterator, module Iter2$ListIterator, module class Iter2$ListIterator$, class Iter2$Nil, module Iter2$Nil, module class Iter2$Nil$, class Iter2$Seq, module Iter2$Seq, module class Iter2$Seq$, class Iter2$SeqTransforms, module Iter2$SeqTransforms, module class Iter2$SeqTransforms$, class Iter2$View, module Iter2$View, module class Iter2$View$, class Iter2, module class Iter2$, module Iter2)
entered: Iter3.scala
typed ident dotty1 in module class <root>
typed ident immutable in module class collections
typed ident annotation in module class immutable
typed ident type Iter2$ in module Iter2
Expansion: def <init>() expands to def <init>()
creating symbol for def <init>() in Mode(ImplicitsEnabled)
entered: method <init> in module class Iter2$ and Scopes()
ensure first is class  -->
completing module class Iter2$, parents = List(), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object))
Expansion: <trait> trait Iterator[A] extends IterableOnce[A] {
  def hasNext: Boolean
  def next: A
  def iterator = this
  def foreach(f: (A) => Unit): Unit = ???
  def map[B](f: (A) => B): Iterator[B] = ???
  def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
  def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
  def drop(n: Int): Iterator[A] = ???
  def indexWhere(p: (A) => Boolean): Int = {
    var i = 0
    while (hasNext) do {
      if (p(next)) return i
      i += 1
    }
    -1
  }
  def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
} expands to <trait> trait Iterator[A]() extends IterableOnce[A] {
  A
  def hasNext: Boolean
  def next: A
  def iterator = this
  def foreach(f: (A) => Unit): Unit = ???
  def map[B](f: (A) => B): Iterator[B] = ???
  def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
  def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
  def drop(n: Int): Iterator[A] = ???
  def indexWhere(p: (A) => Boolean): Int = {
    var i = 0
    while (hasNext) do {
      if (p(next)) return i
      i += 1
    }
    -1
  }
  def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
}
Expansion: <trait> trait IterableOnce[A] extends {
  def iterator: Iterator[A]
  def buildIterator: Iterator[A] = iterator
} expands to <trait> trait IterableOnce[A]() extends {
  A
  def iterator: Iterator[A]
  def buildIterator: Iterator[A] = iterator
}
Expansion: <trait> trait FromIterator[C[X] <: Iterable[X]] extends {
  def fromIterator[B](it: Iterator[B]): C[B]
} expands to <trait> trait FromIterator[C[X] <: Iterable[X]]() extends {
  C[X]
  def fromIterator[B](it: Iterator[B]): C[B]
}
Expansion: <trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[Iterable]
  {
} expands to <trait> trait Iterable[IA]() extends IterableOnce[IA] with FromIterator[Iterable
  ]
 {
  IA
}
Expansion: <trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {
  def apply(i: Int): AA
  def length: Int
} expands to <trait> trait Seq[AA]() extends Iterable[AA] with FromIterator[Seq] {
  AA
  def apply(i: Int): AA
  def length: Int
}
Expansion: <trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {
  def isEmpty: Boolean
  def head: A
  def tail: List[A]
  def iterator = new ListIterator[A](this)
  def fromIterator[B](it: Iterator[B]): List[B] =
    it match {
      case ListIterator(xs) =>
        xs
      case _ =>
        if (it.hasNext) Cons(it.next, fromIterator(it)) else
          Nil.asInstanceOf[List[B]]
    }
  def apply(i: Int): A = {
    require(! isEmpty)
    if (i == 0) head else tail.apply(i - 1)
  }
  def length: Int = if (isEmpty) 0 else 1 + tail.length
} expands to <trait> sealed trait List[A]() extends Seq[A] with FromIterator[List] {
  A
  def isEmpty: Boolean
  def head: A
  def tail: List[A]
  def iterator = new ListIterator[A](this)
  def fromIterator[B](it: Iterator[B]): List[B] =
    it match {
      case ListIterator(xs) =>
        xs
      case _ =>
        if (it.hasNext) Cons(it.next, fromIterator(it)) else
          Nil.asInstanceOf[List[B]]
    }
  def apply(i: Int): A = {
    require(! isEmpty)
    if (i == 0) head else tail.apply(i - 1)
  }
  def length: Int = if (isEmpty) 0 else 1 + tail.length
}
Expansion: case class Cons[A](val x: A, val xs: List[A]) extends List[A] {
  def isEmpty = false
  def head = x
  def tail = xs
} expands to Thicket {
  case class Cons[A](x: A, xs: List[A]) extends List[A] with Product2[A, List[A]
    ]
   {
    A
    val x
    val xs
    def isEmpty = false
    def head = x
    def tail = xs
    def copy[A](x = x @scala.annotation.unchecked.uncheckedVariance(),
      xs = xs @scala.annotation.unchecked.uncheckedVariance()
    ) =
      new
        <derived typetree watching
          case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[...,
            ...
          ] {
            A
            val x
            val xs
            def isEmpty = ...
            def head = ...
            def tail = ...
            def copy[...](..., ...) = ...
            def isDefined = ...
            def _1 = ...
            def _2 = ...
          }
        >
      [...](..., ...)
    ...
    ...
    ...
  }
  final lazy module val Cons: ... = ...
  final module class Cons$() extends ... { this: ... =>
    ...
    ...
  }
 }
Expansion: module case object Nil extends List[Nothing] {
  def isEmpty = true
  def head = ???
  def tail = ???
} expands to Thicket {
  final lazy module case val Nil: Nil$ = new Nil$()
  final module class Nil$() extends List[Nothing] { this: Nil.type =>
    def isEmpty = true
    def head = ???
    def tail = ???
  }
 }
Expansion: class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],
  private[this] val initLen: Int
) extends Seq[A] with FromIterator[ArrayBuffer] {
  def <init>() = {
    <init>(new Array[AnyRef](16), 0)
    ()
  }
  def <init>(it: ArrayIterator[A]) = {
    <init>(it.elems, it.len)
    ()
  }
  private var elems: Array[AnyRef] = initElems
  private var len = 0
  def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
  override def buildIterator =
    new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
  def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
    new ArrayBuffer(ArrayIterator.fromIterator(it))
  def apply(i: Int) = elems(i).asInstanceOf[A]
  def length = len
} expands to class ArrayBuffer[A] private(initElems: Array[AnyRef], initLen: Int) extends Seq
  [
A] with FromIterator[ArrayBuffer] {
  A
  private[this] val initElems
  private[this] val initLen
  def <init>[A]() = {
    <init>(new Array[AnyRef](16), 0)
    ()
  }
  def <init>[A](it: ArrayIterator[A]) = {
    <init>(it.elems, it.len)
    ()
  }
  private var elems: Array[AnyRef] = initElems
  private var len = 0
  def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
  override def buildIterator =
    new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
  def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
    new ArrayBuffer(ArrayIterator.fromIterator(it))
  def apply(i: Int) = elems(i).asInstanceOf[A]
  def length = len
}
Expansion: implicit class IterableTransforms[A, C[X] <: Iterable[X]](
  val c: Iterable[A] & FromIterator[C]
) extends AnyVal {
  def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
  def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
    c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
  def ++[B >: A](xs: IterableOnce[B]): C[B] =
    c.fromIterator(c.buildIterator ++ xs.buildIterator)
  def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
  def head: A = c.iterator.next
  def zip[B](xs: IterableOnce[B]): C[(A, B)] =
    c.fromIterator(c.iterator.zip(xs.iterator))
} expands to Thicket {
  implicit class IterableTransforms[A, C[X] <: Iterable[X]](
    c: Iterable[A] & FromIterator[C]
  ) extends AnyVal {
    A
    C[X]
    val c
    def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
    def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
      c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
    def ++[B >: A](xs: IterableOnce[B]): C[B] =
      c.fromIterator(c.buildIterator ++ xs.buildIterator)
    def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
    def head: A = c.iterator.next
    def zip[B](xs: IterableOnce[B]): C[(A, B)] =
      c.fromIterator(c.iterator.zip(xs.iterator))
  }
  implicit def IterableTransforms[A, C[X] <: Iterable[X]](
    c: Iterable[A] & FromIterator[C]
  ):
    <derived typetree watching
      implicit class IterableTransforms[A..., C[...]...](c: ...) extends AnyVal
        {

A
        C[...]
        val c
        def map[...](...): ... = ...
        def flatMap[...](...): ... = ...
        def ++[...](...): ... = ...
        def drop(...): ... = ...
        def head: ... = ...
        def zip[...](...): ... = ...
      }
    >[..., ...]
   = ...
 }
Expansion: implicit class SeqTransforms[SA, C[X] <: Seq[X]](
  val c: Seq[SA] & FromIterator[C]
) extends AnyVal {
  def reverse: C[SA] = {
    val elems = new Array[AnyRef](c.length)
    var i = elems.length
    val it = c.iterator
    while (it.hasNext) do {
      i -= 1
      elems(i) = it.next.asInstanceOf[AnyRef]
    }
    val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
    xzz
  }
  def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
} expands to Thicket {
  implicit class SeqTransforms[SA, C[X] <: Seq[X]](c: Seq[SA] & FromIterator[C])
     extends
   AnyVal {
    SA
    C[X]
    val c
    def reverse: C[SA] = {
      val elems = new Array[AnyRef](c.length)
      var i = elems.length
      val it = c.iterator
      while (it.hasNext) do {
        i -= 1
        elems(i) = it.next.asInstanceOf[AnyRef]
      }
      val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
      xzz
    }
    def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
  }
  implicit def SeqTransforms[SA, C[X] <: Seq[X]](c: Seq[SA] & FromIterator[C]):
    <derived typetree watching
      implicit class SeqTransforms[SA..., C[...]...](c: ...) extends AnyVal {
        SA
        C[...]
        val c
        def reverse: ... = ...
        def indexWhere(...): ... = ...
      }
    >[..., ...]
   = ...
 }
Expansion: case class ListIterator[A](val xs: List[A]) extends Iterator[A] {
  private[this] var current: List[A] = xs
  def hasNext = ! current.isEmpty
  def next = {
    val res = current.head
    current = current.tail
    res
  }
} expands to Thicket {
  case class ListIterator[A](xs: List[A]) extends Iterator[A] with Product1[
    List[A]
  ] {
    A
    val xs
    private[this] var current: List[A] = xs
    def hasNext = ! current.isEmpty
    def next = {
      val res = current.head
      current = current.tail
      res
    }
    def copy[A](xs = xs @scala.annotation.unchecked.uncheckedVariance()) =
      new
        <derived typetree watching
          case class ListIterator[A...](xs: ...) extends ...[...] with ...[...]
            {

A
            val xs
            private[this] var current: ... = ...
            def hasNext = ...
            def next = ...
            def copy[...](...) = ...
            def isDefined = ...
            def _1 = ...
          }
        >
      [...](...)
    ...
    ...
  }
  final lazy module val ListIterator: ... = ...
  final module class ListIterator$() extends ... { this: ... =>
    ...
    ...
  }
 }
Expansion: case class ArrayIterator[A](val elems: Array[AnyRef], val len: Int) extends
  Iterator
[A] {
  import ArrayIterator._
  private def elem(i: Int) = elems(i).asInstanceOf[A]
  private var cur = 0
  def hasNext = cur < len
  def next = {
    val res = elem(cur)
    cur += 1
    res
  }
  override def foreach(f: (A) => Unit): Unit =
    for i <- 0 until len do f(elem(i))
  override def map[B](f: (A) => B): ArrayIterator[B] = {
    var mapped = elems
    for i <- 0 until len do {
      val x = elem(i)
      val y = widen(f(x))
      if (widen(x) ne y) {
        if (mapped eq elems) mapped = new Array[AnyRef](len)
        mapped(i) = y
      }
    }
    if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
      new ArrayIterator(mapped, len)
  }
  override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
    flatten(map(_$2 => f(_$2).buildIterator))
  override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
    val thatIterator @ ArrayIterator(elems2, len2) = fromIterator(that.iterator)
    if (len == 0) thatIterator else
      if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
        val resLen = len + len2
        val resElems = new Array[AnyRef](resLen)
        Array.copy(elems, 0, resElems, 0, len)
        Array.copy(elems2, 0, resElems, len, len2)
        new ArrayIterator(resElems, resLen)
      }
  }
} expands to Thicket {
  case class ArrayIterator[A](elems: Array[AnyRef], len: Int) extends Iterator[A
    ]
   with Product2[Array[AnyRef], Int] {
    A
    val elems
    val len
    import ArrayIterator._
    private def elem(i: Int) = elems(i).asInstanceOf[A]
    private var cur = 0
    def hasNext = cur < len
    def next = {
      val res = elem(cur)
      cur += 1
      res
    }
    override def foreach(f: (A) => Unit): Unit =
      for i <- 0 until len do f(elem(i))
    override def map[B](f: (A) => B): ArrayIterator[B] = {
      var mapped = elems
      for i <- 0 until len do {
        val x = elem(i)
        val y = widen(f(x))
        if (widen(x) ne y) {
          if (mapped eq elems) mapped = new Array[AnyRef](len)
          mapped(i) = y
        }
      }
      if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
        new ArrayIterator(mapped, len)
    }
    override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
      flatten(map(_$2 => f(_$2).buildIterator))
    override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
      val thatIterator @ ArrayIterator(elems2, len2) =
        fromIterator(that.iterator)
      if (len == 0) thatIterator else
        if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
          val resLen = len + len2
          val resElems = new Array[AnyRef](resLen)
          Array.copy(elems, 0, resElems, 0, len)
          Array.copy(elems2, 0, resElems, len, len2)
          new ArrayIterator(resElems, resLen)
        }
    }
    def copy[A](elems = elems @scala.annotation.unchecked.uncheckedVariance(),
      len = len @scala.annotation.unchecked.uncheckedVariance()
    ) =
      new
        <derived typetree watching
          case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
             with
          ...[..., ...] {
            A
            val elems
            val len
            import ...._
            private def elem(...) = ...
            private var cur = ...
            def hasNext = ...
            def next = ...
            override def foreach(...): ... = ...
            override def map[...](...): ... = ...
            override def flatMap[...](...): ... = ...
            override def ++[...](...): ... = ...
            def copy[...](..., ...) = ...
            def isDefined = ...
            def _1 = ...
            def _2 = ...
          }
        >
      [...](..., ...)
    ...
    ...
    ...
  }
  final lazy module val ArrayIterator: ... = ...
  final module class ArrayIterator$() extends ... { this: ... =>
    ...
    ...
  }
 }
Expansion: module object ArrayIterator extends {
  private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]
  def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =
    it match {
      case it: ArrayIterator[A] =>
        it
      case _ =>
        var elems = new Array[AnyRef](32)
        var len = 0
        def ensureCapacity() = {
          while (len > elems.length) do {
            val newElems = new Array[AnyRef](elems.length * 2)
            Array.copy(elems, 0, newElems, 0, elems.length)
            elems = newElems
          }
        }
        while (it.hasNext) do {
          len += 1
          ensureCapacity()
          elems(len - 1) = widen(it.next)
        }
        ArrayIterator(elems, len)
    }
  def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {
    var arrayIts = its.map(fromIterator)
    var totalLen = 0
    arrayIts.foreach(_$3 => totalLen += _$3.len)
    val allElems = new Array[AnyRef](totalLen)
    var j = 0
    arrayIts.foreach({
      it => {
        Array.copy(it.elems, 0, allElems, j, it.len)
        j += it.len
      }
    })
    new ArrayIterator(allElems, totalLen)
  }
} expands to Thicket {
  final lazy module val ArrayIterator: ArrayIterator$ = new ArrayIterator$()
  final module class ArrayIterator$() extends { this: ArrayIterator.type =>
    private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]
    def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =
      it match {
        case it: ArrayIterator[A] =>
          it
        case _ =>
          var elems = new Array[AnyRef](32)
          var len = 0
          def ensureCapacity() = {
            while (len > elems.length) do {
              val newElems = new Array[AnyRef](elems.length * 2)
              Array.copy(elems, 0, newElems, 0, elems.length)
              elems = newElems
            }
          }
          while (it.hasNext) do {
            len += 1
            ensureCapacity()
            elems(len - 1) = widen(it.next)
          }
          ArrayIterator(elems, len)
      }
    def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {
      var arrayIts = its.map(fromIterator)
      var totalLen = 0
      arrayIts.foreach(_$3 => totalLen += _$3.len)
      val allElems = new Array[AnyRef](totalLen)
      var j = 0
      arrayIts.foreach({
        it => {
          Array.copy(it.elems, 0, allElems, j, it.len)
          j += it.len
        }
      })
      new ArrayIterator(allElems, totalLen)
    }
  }
 }
creating symbol for <trait> trait Iterator[A]() extends IterableOnce[A] {
  A
  def hasNext: Boolean
  def next: A
  def iterator = this
  def foreach(f: (A) => Unit): Unit = ???
  def map[B](f: (A) => B): Iterator[B] = ???
  def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
  def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
  def drop(n: Int): Iterator[A] = ???
  def indexWhere(p: (A) => Boolean): Int = {
    var i = 0
    while (hasNext) do {
      if (p(next)) return i
      i += 1
    }
    -1
  }
  def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
} in Mode(ImplicitsEnabled)
Expansion: A expands to Thicket {
  dotty1$collections$immutable$Iter2$Iterator$$A
  private[this] type A = dotty1$collections$immutable$Iter2$Iterator$$A
 }
creating symbol for dotty1$collections$immutable$Iter2$Iterator$$A in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$Iterator$$A in class Iterator and Scopes()
creating symbol for private[this] type A = dotty1$collections$immutable$Iter2$Iterator$$A in Mode(ImplicitsEnabled)
entered: type A in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A)
entered: class Iterator in module class Iter2$ and Scopes(method <init>)
creating symbol for <trait> trait IterableOnce[A]() extends {
  A
  def iterator: Iterator[A]
  def buildIterator: Iterator[A] = iterator
} in Mode(ImplicitsEnabled)
Expansion: A expands to Thicket {
  dotty1$collections$immutable$Iter2$IterableOnce$$A
  private[this] type A = dotty1$collections$immutable$Iter2$IterableOnce$$A
 }
creating symbol for dotty1$collections$immutable$Iter2$IterableOnce$$A in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$IterableOnce$$A in class IterableOnce and Scopes()
creating symbol for private[this] type A = dotty1$collections$immutable$Iter2$IterableOnce$$A in Mode(ImplicitsEnabled)
entered: type A in class IterableOnce and Scopes(type dotty1$collections$immutable$Iter2$IterableOnce$$A)
entered: class IterableOnce in module class Iter2$ and Scopes(method <init>, class Iterator)
creating symbol for <trait> trait FromIterator[C[X] <: Iterable[X]]() extends {
  C[X]
  def fromIterator[B](it: Iterator[B]): C[B]
} in Mode(ImplicitsEnabled)
Expansion: C[X] expands to Thicket {
  dotty1$collections$immutable$Iter2$FromIterator$$C[X]
  private[this] type C = dotty1$collections$immutable$Iter2$FromIterator$$C
 }
creating symbol for dotty1$collections$immutable$Iter2$FromIterator$$C[X] in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$FromIterator$$C in class FromIterator and Scopes()
creating symbol for private[this] type C = dotty1$collections$immutable$Iter2$FromIterator$$C in Mode(ImplicitsEnabled)
entered: type C in class FromIterator and Scopes(type dotty1$collections$immutable$Iter2$FromIterator$$C)
entered: class FromIterator in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce)
creating symbol for <trait> trait Iterable[IA]() extends IterableOnce[IA] with FromIterator[Iterable
  ]
 {
  IA
} in Mode(ImplicitsEnabled)
Expansion: IA expands to Thicket {
  dotty1$collections$immutable$Iter2$Iterable$$IA
  private[this] type IA = dotty1$collections$immutable$Iter2$Iterable$$IA
 }
creating symbol for dotty1$collections$immutable$Iter2$Iterable$$IA in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$Iterable$$IA in class Iterable and Scopes()
creating symbol for private[this] type IA = dotty1$collections$immutable$Iter2$Iterable$$IA in Mode(ImplicitsEnabled)
entered: type IA in class Iterable and Scopes(type dotty1$collections$immutable$Iter2$Iterable$$IA)
entered: class Iterable in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator)
creating symbol for <trait> trait Seq[AA]() extends Iterable[AA] with FromIterator[Seq] {
  AA
  def apply(i: Int): AA
  def length: Int
} in Mode(ImplicitsEnabled)
Expansion: AA expands to Thicket {
  dotty1$collections$immutable$Iter2$Seq$$AA
  private[this] type AA = dotty1$collections$immutable$Iter2$Seq$$AA
 }
creating symbol for dotty1$collections$immutable$Iter2$Seq$$AA in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$Seq$$AA in class Seq and Scopes()
creating symbol for private[this] type AA = dotty1$collections$immutable$Iter2$Seq$$AA in Mode(ImplicitsEnabled)
entered: type AA in class Seq and Scopes(type dotty1$collections$immutable$Iter2$Seq$$AA)
entered: class Seq in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable)
creating symbol for <trait> sealed trait List[A]() extends Seq[A] with FromIterator[List] {
  A
  def isEmpty: Boolean
  def head: A
  def tail: List[A]
  def iterator = new ListIterator[A](this)
  def fromIterator[B](it: Iterator[B]): List[B] =
    it match {
      case ListIterator(xs) =>
        xs
      case _ =>
        if (it.hasNext) Cons(it.next, fromIterator(it)) else
          Nil.asInstanceOf[List[B]]
    }
  def apply(i: Int): A = {
    require(! isEmpty)
    if (i == 0) head else tail.apply(i - 1)
  }
  def length: Int = if (isEmpty) 0 else 1 + tail.length
} in Mode(ImplicitsEnabled)
Expansion: A expands to Thicket {
  dotty1$collections$immutable$Iter2$List$$A
  private[this] type A = dotty1$collections$immutable$Iter2$List$$A
 }
creating symbol for dotty1$collections$immutable$Iter2$List$$A in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$List$$A in class List and Scopes()
creating symbol for private[this] type A = dotty1$collections$immutable$Iter2$List$$A in Mode(ImplicitsEnabled)
entered: type A in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A)
entered: class List in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq)
creating symbol for case class Cons[A](x: A, xs: List[A]) extends List[A] with Product2[A, List[A]]
  {

A
  val x
  val xs
  def isEmpty = false
  def head = x
  def tail = xs
  def copy[A](x = x @scala.annotation.unchecked.uncheckedVariance(),
    xs = xs @scala.annotation.unchecked.uncheckedVariance()
  ) =
    new
      <derived typetree watching
        case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[...,
          ...
        ] {
          A
          val x
          val xs
          def isEmpty = ...
          def head = ...
          def tail = ...
          def copy[...](..., ...) = ...
          def isDefined = ...
          def _1 = ...
          def _2 = ...
        }
      >
    [...](..., ...)
  def isDefined = ...
  def _1 = ...
  def _2 = ...
} in Mode(ImplicitsEnabled)
Expansion: A expands to Thicket {
  dotty1$collections$immutable$Iter2$Cons$$A
  private[this] type A = dotty1$collections$immutable$Iter2$Cons$$A
 }
Expansion: val x expands to val x
Expansion: val xs expands to val xs
creating symbol for dotty1$collections$immutable$Iter2$Cons$$A in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$Cons$$A in class Cons and Scopes()
creating symbol for private[this] type A = dotty1$collections$immutable$Iter2$Cons$$A in Mode(ImplicitsEnabled)
entered: type A in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A)
creating symbol for val x in Mode(ImplicitsEnabled)
entered: val x in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A)
creating symbol for val xs in Mode(ImplicitsEnabled)
entered: val xs in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A, val x)
entered: class Cons in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List)
creating symbol for final lazy module val Cons: Cons$ = new Cons$() in Mode(ImplicitsEnabled)
entered: module Cons in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons)
creating symbol for final module class Cons$() extends AnyRef { this: Cons.type =>
  def apply[A](x, xs) =
    new
      <derived typetree watching
        case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[...,
          ...
        ] {
          A
          val x
          val xs
          def isEmpty = ...
          def head = ...
          def tail = ...
          def copy[...](..., ...) = ...
          def isDefined = ...
          def _1 = ...
          def _2 = ...
        }
      >
    [...](..., ...)
  def unapply[...](...) = ...
} in Mode(ImplicitsEnabled)
entered: module class Cons$ in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons)
creating symbol for final lazy module case val Nil: Nil$ = new Nil$() in Mode(ImplicitsEnabled)
entered: module Nil in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$)
creating symbol for final module class Nil$() extends List[Nothing] { this: Nil.type =>
  def isEmpty = true
  def head = ???
  def tail = ???
} in Mode(ImplicitsEnabled)
entered: module class Nil$ in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil)
creating symbol for class ArrayBuffer[A] private(initElems: Array[AnyRef], initLen: Int) extends Seq
  [
A] with FromIterator[ArrayBuffer] {
  A
  private[this] val initElems
  private[this] val initLen
  def <init>[A]() = {
    <init>(new Array[AnyRef](16), 0)
    ()
  }
  def <init>[A](it: ArrayIterator[A]) = {
    <init>(it.elems, it.len)
    ()
  }
  private var elems: Array[AnyRef] = initElems
  private var len = 0
  def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
  override def buildIterator =
    new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
  def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
    new ArrayBuffer(ArrayIterator.fromIterator(it))
  def apply(i: Int) = elems(i).asInstanceOf[A]
  def length = len
} in Mode(ImplicitsEnabled)
Expansion: A expands to Thicket {
  dotty1$collections$immutable$Iter2$ArrayBuffer$$A
  private[this] type A = dotty1$collections$immutable$Iter2$ArrayBuffer$$A
 }
Expansion: private[this] val initElems expands to private[this] val initElems
Expansion: private[this] val initLen expands to private[this] val initLen
creating symbol for dotty1$collections$immutable$Iter2$ArrayBuffer$$A in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$ArrayBuffer$$A in class ArrayBuffer and Scopes()
creating symbol for private[this] type A = dotty1$collections$immutable$Iter2$ArrayBuffer$$A in Mode(ImplicitsEnabled)
entered: type A in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A)
creating symbol for private[this] val initElems in Mode(ImplicitsEnabled)
entered: val initElems in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A)
creating symbol for private[this] val initLen in Mode(ImplicitsEnabled)
entered: val initLen in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems)
entered: class ArrayBuffer in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$)
creating symbol for implicit class IterableTransforms[A, C[X] <: Iterable[X]](
  c: Iterable[A] & FromIterator[C]
) extends AnyVal {
  A
  C[X]
  val c
  def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
  def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
    c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
  def ++[B >: A](xs: IterableOnce[B]): C[B] =
    c.fromIterator(c.buildIterator ++ xs.buildIterator)
  def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
  def head: A = c.iterator.next
  def zip[B](xs: IterableOnce[B]): C[(A, B)] =
    c.fromIterator(c.iterator.zip(xs.iterator))
} in Mode(ImplicitsEnabled)
Expansion: A expands to Thicket {
  dotty1$collections$immutable$Iter2$IterableTransforms$$A
  private[this] type A =
    dotty1$collections$immutable$Iter2$IterableTransforms$$A
 }
Expansion: C[X] expands to Thicket {
  dotty1$collections$immutable$Iter2$IterableTransforms$$C[X]
  private[this] type C =
    dotty1$collections$immutable$Iter2$IterableTransforms$$C
 }
Expansion: val c expands to val c
creating symbol for dotty1$collections$immutable$Iter2$IterableTransforms$$A in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$IterableTransforms$$A in class IterableTransforms and Scopes()
creating symbol for private[this] type A = dotty1$collections$immutable$Iter2$IterableTransforms$$A in Mode(ImplicitsEnabled)
entered: type A in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A)
creating symbol for dotty1$collections$immutable$Iter2$IterableTransforms$$C[X] in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$IterableTransforms$$C in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A)
creating symbol for private[this] type C = dotty1$collections$immutable$Iter2$IterableTransforms$$C in Mode(ImplicitsEnabled)
entered: type C in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C)
creating symbol for val c in Mode(ImplicitsEnabled)
entered: val c in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C)
entered: class IterableTransforms in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer)
creating symbol for implicit def IterableTransforms[A, C[X] <: Iterable[X]](
  c: Iterable[A] & FromIterator[C]
):
  <derived typetree watching
    implicit class IterableTransforms[A..., C[...]...](c: ...) extends AnyVal {
      A
      C[...]
      val c
      def map[...](...): ... = ...
      def flatMap[...](...): ... = ...
      def ++[...](...): ... = ...
      def drop(...): ... = ...
      def head: ... = ...
      def zip[...](...): ... = ...
    }
  >[..., ...]
 = ...(...) in Mode(ImplicitsEnabled)
entered: method IterableTransforms in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms)
creating symbol for implicit class SeqTransforms[SA, C[X] <: Seq[X]](c: Seq[SA] & FromIterator[C])
   extends
 AnyVal {
  SA
  C[X]
  val c
  def reverse: C[SA] = {
    val elems = new Array[AnyRef](c.length)
    var i = elems.length
    val it = c.iterator
    while (it.hasNext) do {
      i -= 1
      elems(i) = it.next.asInstanceOf[AnyRef]
    }
    val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
    xzz
  }
  def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
} in Mode(ImplicitsEnabled)
Expansion: SA expands to Thicket {
  dotty1$collections$immutable$Iter2$SeqTransforms$$SA
  private[this] type SA = dotty1$collections$immutable$Iter2$SeqTransforms$$SA
 }
Expansion: C[X] expands to Thicket {
  dotty1$collections$immutable$Iter2$SeqTransforms$$C[X]
  private[this] type C = dotty1$collections$immutable$Iter2$SeqTransforms$$C
 }
Expansion: val c expands to val c
creating symbol for dotty1$collections$immutable$Iter2$SeqTransforms$$SA in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$SeqTransforms$$SA in class SeqTransforms and Scopes()
creating symbol for private[this] type SA = dotty1$collections$immutable$Iter2$SeqTransforms$$SA in Mode(ImplicitsEnabled)
entered: type SA in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA)
creating symbol for dotty1$collections$immutable$Iter2$SeqTransforms$$C[X] in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$SeqTransforms$$C in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA, type SA)
creating symbol for private[this] type C = dotty1$collections$immutable$Iter2$SeqTransforms$$C in Mode(ImplicitsEnabled)
entered: type C in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA, type SA, type dotty1$collections$immutable$Iter2$SeqTransforms$$C)
creating symbol for val c in Mode(ImplicitsEnabled)
entered: val c in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA, type SA, type dotty1$collections$immutable$Iter2$SeqTransforms$$C, type C)
entered: class SeqTransforms in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms)
creating symbol for implicit def SeqTransforms[SA, C[X] <: Seq[X]](c: Seq[SA] & FromIterator[C]):
  <derived typetree watching
    implicit class SeqTransforms[SA..., C[...]...](c: ...) extends AnyVal {
      SA
      C[...]
      val c
      def reverse: ... = ...
      def indexWhere(...): ... = ...
    }
  >[..., ...]
 = ...(...) in Mode(ImplicitsEnabled)
entered: method SeqTransforms in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms)
creating symbol for case class ListIterator[A](xs: List[A]) extends Iterator[A] with Product1[
  List[A]
] {
  A
  val xs
  private[this] var current: List[A] = xs
  def hasNext = ! current.isEmpty
  def next = {
    val res = current.head
    current = current.tail
    res
  }
  def copy[A](xs = xs @scala.annotation.unchecked.uncheckedVariance()) =
    new
      <derived typetree watching
        case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
          A
          val xs
          private[this] var current: ... = ...
          def hasNext = ...
          def next = ...
          def copy[...](...) = ...
          def isDefined = ...
          def _1 = ...
        }
      >
    [...](...)
  def isDefined = ...
  def _1 = ...
} in Mode(ImplicitsEnabled)
Expansion: A expands to Thicket {
  dotty1$collections$immutable$Iter2$ListIterator$$A
  private[this] type A = dotty1$collections$immutable$Iter2$ListIterator$$A
 }
Expansion: val xs expands to val xs
creating symbol for dotty1$collections$immutable$Iter2$ListIterator$$A in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$ListIterator$$A in class ListIterator and Scopes()
creating symbol for private[this] type A = dotty1$collections$immutable$Iter2$ListIterator$$A in Mode(ImplicitsEnabled)
entered: type A in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A)
creating symbol for val xs in Mode(ImplicitsEnabled)
entered: val xs in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A)
entered: class ListIterator in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms, method SeqTransforms)
creating symbol for final lazy module val ListIterator: ListIterator$ = new ListIterator$() in Mode(ImplicitsEnabled)
entered: module ListIterator in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms, method SeqTransforms, class ListIterator)
creating symbol for final module class ListIterator$() extends AnyRef { this: ListIterator.type =>
  def apply[A](xs) =
    new
      <derived typetree watching
        case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
          A
          val xs
          private[this] var current: ... = ...
          def hasNext = ...
          def next = ...
          def copy[...](...) = ...
          def isDefined = ...
          def _1 = ...
        }
      >
    [...](...)
  def unapply[...](...) = ...
} in Mode(ImplicitsEnabled)
entered: module class ListIterator$ in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms, method SeqTransforms, class ListIterator, module ListIterator)
creating symbol for case class ArrayIterator[A](elems: Array[AnyRef], len: Int) extends Iterator[A]
   with
Product2[Array[AnyRef], Int] {
  A
  val elems
  val len
  import ArrayIterator._
  private def elem(i: Int) = elems(i).asInstanceOf[A]
  private var cur = 0
  def hasNext = cur < len
  def next = {
    val res = elem(cur)
    cur += 1
    res
  }
  override def foreach(f: (A) => Unit): Unit =
    for i <- 0 until len do f(elem(i))
  override def map[B](f: (A) => B): ArrayIterator[B] = {
    var mapped = elems
    for i <- 0 until len do {
      val x = elem(i)
      val y = widen(f(x))
      if (widen(x) ne y) {
        if (mapped eq elems) mapped = new Array[AnyRef](len)
        mapped(i) = y
      }
    }
    if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
      new ArrayIterator(mapped, len)
  }
  override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
    flatten(map(_$2 => f(_$2).buildIterator))
  override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
    val thatIterator @ ArrayIterator(elems2, len2) = fromIterator(that.iterator)
    if (len == 0) thatIterator else
      if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
        val resLen = len + len2
        val resElems = new Array[AnyRef](resLen)
        Array.copy(elems, 0, resElems, 0, len)
        Array.copy(elems2, 0, resElems, len, len2)
        new ArrayIterator(resElems, resLen)
      }
  }
  def copy[A](elems = elems @scala.annotation.unchecked.uncheckedVariance(),
    len = len @scala.annotation.unchecked.uncheckedVariance()
  ) =
    new
      <derived typetree watching
        case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
           with
        ...[..., ...] {
          A
          val elems
          val len
          import ...._
          private def elem(...) = ...
          private var cur = ...
          def hasNext = ...
          def next = ...
          override def foreach(...): ... = ...
          override def map[...](...): ... = ...
          override def flatMap[...](...): ... = ...
          override def ++[...](...): ... = ...
          def copy[...](..., ...) = ...
          def isDefined = ...
          def _1 = ...
          def _2 = ...
        }
      >
    [...](..., ...)
  def isDefined = ...
  def _1 = ...
  def _2 = ...
} in Mode(ImplicitsEnabled)
Expansion: A expands to Thicket {
  dotty1$collections$immutable$Iter2$ArrayIterator$$A
  private[this] type A = dotty1$collections$immutable$Iter2$ArrayIterator$$A
 }
Expansion: val elems expands to val elems
Expansion: val len expands to val len
creating symbol for dotty1$collections$immutable$Iter2$ArrayIterator$$A in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$ArrayIterator$$A in class ArrayIterator and Scopes()
creating symbol for private[this] type A = dotty1$collections$immutable$Iter2$ArrayIterator$$A in Mode(ImplicitsEnabled)
entered: type A in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A)
creating symbol for val elems in Mode(ImplicitsEnabled)
entered: val elems in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A)
creating symbol for val len in Mode(ImplicitsEnabled)
entered: val len in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems)
entered: class ArrayIterator in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms, method SeqTransforms, class ListIterator, module ListIterator, module class ListIterator$)
creating symbol for final lazy module val ArrayIterator: ArrayIterator$ = new ArrayIterator$() in Mode(ImplicitsEnabled)
entered: module ArrayIterator in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms, method SeqTransforms, class ListIterator, module ListIterator, module class ListIterator$, class ArrayIterator)
creating symbol for final module class ArrayIterator$() extends { this: ArrayIterator.type =>
  def apply[A](elems, len) =
    new
      <derived typetree watching
        case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
           with
        ...[..., ...] {
          A
          val elems
          val len
          import ...._
          private def elem(...) = ...
          private var cur = ...
          def hasNext = ...
          def next = ...
          override def foreach(...): ... = ...
          override def map[...](...): ... = ...
          override def flatMap[...](...): ... = ...
          override def ++[...](...): ... = ...
          def copy[...](..., ...) = ...
          def isDefined = ...
          def _1 = ...
          def _2 = ...
        }
      >
    [...](..., ...)
  def unapply[...](...) = ...
  private def widen(...): ... = ...
  def fromIterator[...](...): ... = ...
  def flatten[...](...): ... = ...
} in Mode(ImplicitsEnabled)
entered: module class ArrayIterator$ in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms, method SeqTransforms, class ListIterator, module ListIterator, module class ListIterator$, class ArrayIterator, module ArrayIterator)
typed ident type Iter2$ in module Iter2
ensure first is class  -->
typed ident Iter2 in module class immutable
Expansion: def <init>[A]() expands to def <init>[A]()
creating symbol for def <init>[A]() in Mode(ImplicitsEnabled)
entered: method <init> in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
typed ident type IterableOnce in method <init>
Expansion: def <init>[A]() expands to def <init>[A]()
creating symbol for def <init>[A]() in Mode(ImplicitsEnabled)
entered: method <init> in class IterableOnce and Scopes(type dotty1$collections$immutable$Iter2$IterableOnce$$A, type A)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
ensure first is class  -->
completing class IterableOnce, parents = List(), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object))
Expansion: def iterator: Iterator[A] expands to def iterator: Iterator[A]
Expansion: def buildIterator: Iterator[A] = iterator expands to def buildIterator: Iterator[A] = iterator
creating symbol for def iterator: Iterator[A] in Mode(ImplicitsEnabled)
entered: method iterator in class IterableOnce and Scopes(type dotty1$collections$immutable$Iter2$IterableOnce$$A, type A, method <init>)
creating symbol for def buildIterator: Iterator[A] = iterator in Mode(ImplicitsEnabled)
entered: method buildIterator in class IterableOnce and Scopes(type dotty1$collections$immutable$Iter2$IterableOnce$$A, type A, method <init>, method iterator)
typed ident type A in method <init>
typed ident type dotty1$collections$immutable$Iter2$Iterator$$A in type A
ensure first is class dotty1.collections.immutable.Iter2.IterableOnce[
  dotty1$collections$immutable$Iter2$Iterator$$A
] --> Object
completing class Iterator, parents = List(AppliedTypeTree(Ident(IterableOnce),List(Ident(A)))), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),IterableOnce), dotty1$collections$immutable$Iter2$IterableOnce$$A, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Iterator)),dotty1$collections$immutable$Iter2$Iterator$$A)) | -870875996)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),IterableOnce))
Expansion: def hasNext: Boolean expands to def hasNext: Boolean
Expansion: def next: A expands to def next: A
Expansion: def iterator = this expands to def iterator = this
Expansion: def foreach(f: (A) => Unit): Unit = ??? expands to def foreach(f: (A) => Unit): Unit = ???
Expansion: def map[B](f: (A) => B): Iterator[B] = ??? expands to def map[B](f: (A) => B): Iterator[B] = ???
Expansion: def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ??? expands to def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
Expansion: def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ??? expands to def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
Expansion: def drop(n: Int): Iterator[A] = ??? expands to def drop(n: Int): Iterator[A] = ???
Expansion: def indexWhere(p: (A) => Boolean): Int = {
  var i = 0
  while (hasNext) do {
    if (p(next)) return i
    i += 1
  }
  -1
} expands to def indexWhere(p: (A) => Boolean): Int = {
  var i = 0
  while (hasNext) do {
    if (p(next)) return i
    i += 1
  }
  -1
}
Expansion: def zip[B](that: Iterator[B]): Iterator[(A, B)] = ??? expands to def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
creating symbol for def hasNext: Boolean in Mode(ImplicitsEnabled)
entered: method hasNext in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A)
creating symbol for def next: A in Mode(ImplicitsEnabled)
entered: method next in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext)
creating symbol for def iterator = this in Mode(ImplicitsEnabled)
entered: method iterator in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next)
creating symbol for def foreach(f: (A) => Unit): Unit = ??? in Mode(ImplicitsEnabled)
entered: method foreach in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator)
creating symbol for def map[B](f: (A) => B): Iterator[B] = ??? in Mode(ImplicitsEnabled)
entered: method map in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator, method foreach)
creating symbol for def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ??? in Mode(ImplicitsEnabled)
entered: method flatMap in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator, method foreach, method map)
creating symbol for def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ??? in Mode(ImplicitsEnabled)
entered: method $plus$plus in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator, method foreach, method map, method flatMap)
creating symbol for def drop(n: Int): Iterator[A] = ??? in Mode(ImplicitsEnabled)
entered: method drop in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator, method foreach, method map, method flatMap, method $plus$plus)
creating symbol for def indexWhere(p: (A) => Boolean): Int = {
  var i = 0
  while (hasNext) do {
    if (p(next)) return i
    i += 1
  }
  -1
} in Mode(ImplicitsEnabled)
entered: method indexWhere in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator, method foreach, method map, method flatMap, method $plus$plus, method drop)
creating symbol for def zip[B](that: Iterator[B]): Iterator[(A, B)] = ??? in Mode(ImplicitsEnabled)
entered: method zip in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator, method foreach, method map, method flatMap, method $plus$plus, method drop, method indexWhere)
ensure first is class dotty1.collections.immutable.Iter2.IterableOnce[
  dotty1$collections$immutable$Iter2$Iterator$$A
] --> Object
typed ident type Boolean in method hasNext
typed ident type A in method next
typed ident type Iterator in method iterator
typed ident type A in method iterator
typed ident type dotty1$collections$immutable$Iter2$IterableOnce$$A in type A
using inherited type for iterator; raw: =>
  dotty1.collections.immutable.Iter2.Iterator[
    dotty1$collections$immutable$Iter2$IterableOnce$$A
  ], inst: =>
  dotty1.collections.immutable.Iter2.Iterator[
    dotty1$collections$immutable$Iter2$IterableOnce$$A
  ], inherited: dotty1.collections.immutable.Iter2.Iterator[
  dotty1$collections$immutable$Iter2$Iterator$$A
]
Expansion: f: (A) => Unit expands to f: (A) => Unit
creating symbol for f: (A) => Unit in Mode(ImplicitsEnabled)
entered: val f in method foreach and Scopes()
typed ident type A in val f
typed ident type Unit in val f
typed ident type Unit in method foreach
typed ident $qmark$qmark$qmark in method foreach
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method map and Scopes()
Expansion: f: (A) => B expands to f: (A) => B
creating symbol for f: (A) => B in Mode(ImplicitsEnabled)
entered: val f in method map and Scopes(type B)
typed ident type A in val f
typed ident type B in val f
typed ident type Iterator in method map
typed ident type B in method map
typed ident $qmark$qmark$qmark in method map
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method flatMap and Scopes()
Expansion: f: (A) => IterableOnce[B] expands to f: (A) => IterableOnce[B]
creating symbol for f: (A) => IterableOnce[B] in Mode(ImplicitsEnabled)
entered: val f in method flatMap and Scopes(type B)
typed ident type A in val f
typed ident type IterableOnce in val f
typed ident type B in val f
typed ident type Iterator in method flatMap
typed ident type B in method flatMap
typed ident $qmark$qmark$qmark in method flatMap
Expansion: B >: A expands to B >: A
creating symbol for B >: A in Mode(ImplicitsEnabled)
entered: type B in method $plus$plus and Scopes()
typed ident type A in type B
Expansion: xs: IterableOnce[B] expands to xs: IterableOnce[B]
creating symbol for xs: IterableOnce[B] in Mode(ImplicitsEnabled)
entered: val xs in method $plus$plus and Scopes(type B)
typed ident type IterableOnce in val xs
typed ident type B in val xs
typed ident type Iterator in method $plus$plus
typed ident type B in method $plus$plus
typed ident $qmark$qmark$qmark in method $plus$plus
Expansion: n: Int expands to n: Int
creating symbol for n: Int in Mode(ImplicitsEnabled)
entered: val n in method drop and Scopes()
typed ident type Int in val n
typed ident type Iterator in method drop
typed ident type A in method drop
typed ident $qmark$qmark$qmark in method drop
Expansion: p: (A) => Boolean expands to p: (A) => Boolean
creating symbol for p: (A) => Boolean in Mode(ImplicitsEnabled)
entered: val p in method indexWhere and Scopes()
typed ident type A in val p
typed ident type Boolean in val p
typed ident type Int in method indexWhere
Expansion: var i = 0 expands to var i = 0
creating symbol for var i = 0 in Mode(ImplicitsEnabled)
entered: val i in method indexWhere and Scopes()
Expansion: <label> def while$(): Unit =
  if (hasNext) {
    {
      if (p(next)) return i
      i += 1
    }
    while$()
  } else () expands to <label> def while$(): Unit =
  if (hasNext) {
    {
      if (p(next)) return i
      i += 1
    }
    while$()
  } else ()
creating symbol for <label> def while$(): Unit =
  if (hasNext) {
    {
      if (p(next)) return i
      i += 1
    }
    while$()
  } else () in Mode(ImplicitsEnabled)
entered: method while$ in method indexWhere and Scopes()
typed ident hasNext in method while$
typed ident p in method while$
typed ident next in method while$
typed ident i in method while$
typed ident i in method while$
adapt to subtype Int(i) !<:< ?{ += : ? }
Expansion: A expands to A
Expansion: C[X] <: Iterable[X] expands to C[X] <: Iterable[X]
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method IterableTransforms and Scopes()
creating symbol for C[X] <: Iterable[X] in Mode(ImplicitsEnabled)
entered: type C in method IterableTransforms and Scopes(type A)
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type C and Scopes()
typed ident type Iterable in type C
Expansion: def <init>[IA]() expands to def <init>[IA]()
creating symbol for def <init>[IA]() in Mode(ImplicitsEnabled)
entered: method <init> in class Iterable and Scopes(type dotty1$collections$immutable$Iter2$Iterable$$IA, type IA)
Expansion: IA expands to IA
creating symbol for IA in Mode(ImplicitsEnabled)
entered: type IA in method <init> and Scopes()
typed ident type IterableOnce in method <init>
typed ident type IA in method <init>
typed ident type dotty1$collections$immutable$Iter2$Iterable$$IA in type IA
typed ident type FromIterator in method <init>
Expansion: def <init>[C[X] <: Iterable[X]]() expands to def <init>[C[X] <: Iterable[X]]()
creating symbol for def <init>[C[X] <: Iterable[X]]() in Mode(ImplicitsEnabled)
entered: method <init> in class FromIterator and Scopes(type dotty1$collections$immutable$Iter2$FromIterator$$C, type C)
Expansion: C[X] <: Iterable[X] expands to C[X] <: Iterable[X]
creating symbol for C[X] <: Iterable[X] in Mode(ImplicitsEnabled)
entered: type C in method <init> and Scopes()
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type C and Scopes()
typed ident type Iterable in type C
typed ident type X in type C
ensure first is class  -->
completing class FromIterator, parents = List(), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object))
Expansion: def fromIterator[B](it: Iterator[B]): C[B] expands to def fromIterator[B](it: Iterator[B]): C[B]
creating symbol for def fromIterator[B](it: Iterator[B]): C[B] in Mode(ImplicitsEnabled)
entered: method fromIterator in class FromIterator and Scopes(type dotty1$collections$immutable$Iter2$FromIterator$$C, type C, method <init>)
typed ident type Iterable in method <init>
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type dotty1$collections$immutable$Iter2$FromIterator$$C and Scopes()
ensure first is class dotty1.collections.immutable.Iter2.IterableOnce[
  dotty1$collections$immutable$Iter2$Iterable$$IA
], dotty1.collections.immutable.Iter2.FromIterator[
  dotty1.collections.immutable.Iter2.Iterable
] --> Object, Object
completing class Iterable, parents = List(AppliedTypeTree(Ident(IterableOnce),List(Ident(IA))), AppliedTypeTree(Ident(FromIterator),List(Ident(Iterable)))), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),IterableOnce), dotty1$collections$immutable$Iter2$IterableOnce$$A, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Iterable)),dotty1$collections$immutable$Iter2$Iterable$$IA)) | -982015802), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),FromIterator), dotty1$collections$immutable$Iter2$FromIterator$$C, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Iterable)) | -2016191448)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),IterableOnce), TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),FromIterator))
typed ident type X in type C
Expansion: c: Iterable[A] & FromIterator[C] expands to c: Iterable[A] & FromIterator[C]
creating symbol for c: Iterable[A] & FromIterator[C] in Mode(ImplicitsEnabled)
entered: val c in method IterableTransforms and Scopes(type A, type C)
typed ident type Iterable in val c
typed ident type A in val c
typed ident type FromIterator in val c
typed ident type C in val c
typed ident type A in method IterableTransforms
typed ident type C in method IterableTransforms
Expansion: def <init>[A, C[X] <: dotty1.collections.immutable.Iter2.Iterable[X]](
  c:
    dotty1.collections.immutable.Iter2.Iterable[A] &
      dotty1.collections.immutable.Iter2.FromIterator[C]
) expands to def <init>[A, C[X] <: dotty1.collections.immutable.Iter2.Iterable[X]](
  c:
    dotty1.collections.immutable.Iter2.Iterable[A] &
      dotty1.collections.immutable.Iter2.FromIterator[C]
)
creating symbol for def <init>[A, C[X] <: dotty1.collections.immutable.Iter2.Iterable[X]](
  c:
    dotty1.collections.immutable.Iter2.Iterable[A] &
      dotty1.collections.immutable.Iter2.FromIterator[C]
) in Mode(ImplicitsEnabled)
entered: method <init> in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c)
Expansion: A expands to A
Expansion: C[X] <: dotty1.collections.immutable.Iter2.Iterable[X] expands to C[X] <: dotty1.collections.immutable.Iter2.Iterable[X]
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
creating symbol for C[X] <: dotty1.collections.immutable.Iter2.Iterable[X] in Mode(ImplicitsEnabled)
entered: type C in method <init> and Scopes(type A)
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type C and Scopes()
typed ident type Iterable in type C
typed ident type X in type C
Expansion: c:
  dotty1.collections.immutable.Iter2.Iterable[A] &
    dotty1.collections.immutable.Iter2.FromIterator[C] expands to c:
  dotty1.collections.immutable.Iter2.Iterable[A] &
    dotty1.collections.immutable.Iter2.FromIterator[C]
creating symbol for c:
  dotty1.collections.immutable.Iter2.Iterable[A] &
    dotty1.collections.immutable.Iter2.FromIterator[C] in Mode(ImplicitsEnabled)
entered: val c in method <init> and Scopes(type A, type C)
typed ident type Iterable in val c
typed ident type A in val c
typed ident type FromIterator in val c
typed ident type C in val c
typed ident type AnyVal in method <init>
completing class IterableTransforms, parents = List(Ident(AnyVal)), parentTypes = List(TypeRef(TermRef(ThisType(TypeRef(NoPrefix,<root>)),scala),AnyVal)), parentRefs = List(TypeRef(TermRef(ThisType(TypeRef(NoPrefix,<root>)),scala),AnyVal))
Expansion: def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f)) expands to def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
Expansion: def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
  c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator)) expands to def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
  c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
Expansion: def ++[B >: A](xs: IterableOnce[B]): C[B] =
  c.fromIterator(c.buildIterator ++ xs.buildIterator) expands to def ++[B >: A](xs: IterableOnce[B]): C[B] =
  c.fromIterator(c.buildIterator ++ xs.buildIterator)
Expansion: def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n)) expands to def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
Expansion: def head: A = c.iterator.next expands to def head: A = c.iterator.next
Expansion: def zip[B](xs: IterableOnce[B]): C[(A, B)] =
  c.fromIterator(c.iterator.zip(xs.iterator)) expands to def zip[B](xs: IterableOnce[B]): C[(A, B)] =
  c.fromIterator(c.iterator.zip(xs.iterator))
creating symbol for def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f)) in Mode(ImplicitsEnabled)
entered: method map in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c, method <init>)
creating symbol for def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
  c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator)) in Mode(ImplicitsEnabled)
entered: method flatMap in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c, method <init>, method map)
creating symbol for def ++[B >: A](xs: IterableOnce[B]): C[B] =
  c.fromIterator(c.buildIterator ++ xs.buildIterator) in Mode(ImplicitsEnabled)
entered: method $plus$plus in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c, method <init>, method map, method flatMap)
creating symbol for def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n)) in Mode(ImplicitsEnabled)
entered: method drop in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c, method <init>, method map, method flatMap, method $plus$plus)
creating symbol for def head: A = c.iterator.next in Mode(ImplicitsEnabled)
entered: method head in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c, method <init>, method map, method flatMap, method $plus$plus, method drop)
creating symbol for def zip[B](xs: IterableOnce[B]): C[(A, B)] =
  c.fromIterator(c.iterator.zip(xs.iterator)) in Mode(ImplicitsEnabled)
entered: method zip in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c, method <init>, method map, method flatMap, method $plus$plus, method drop, method head)
typed ident type dotty1$collections$immutable$Iter2$IterableTransforms$$A in type A
typed ident type dotty1$collections$immutable$Iter2$IterableTransforms$$C in type C
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type dotty1$collections$immutable$Iter2$IterableTransforms$$C and Scopes()
Expansion: SA expands to SA
Expansion: C[X] <: Seq[X] expands to C[X] <: Seq[X]
creating symbol for SA in Mode(ImplicitsEnabled)
entered: type SA in method SeqTransforms and Scopes()
creating symbol for C[X] <: Seq[X] in Mode(ImplicitsEnabled)
entered: type C in method SeqTransforms and Scopes(type SA)
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type C and Scopes()
typed ident type Seq in type C
Expansion: def <init>[AA]() expands to def <init>[AA]()
creating symbol for def <init>[AA]() in Mode(ImplicitsEnabled)
entered: method <init> in class Seq and Scopes(type dotty1$collections$immutable$Iter2$Seq$$AA, type AA)
Expansion: AA expands to AA
creating symbol for AA in Mode(ImplicitsEnabled)
entered: type AA in method <init> and Scopes()
typed ident type Iterable in method <init>
typed ident type AA in method <init>
typed ident type dotty1$collections$immutable$Iter2$Seq$$AA in type AA
typed ident type FromIterator in method <init>
typed ident type Seq in method <init>
ensure first is class dotty1.collections.immutable.Iter2.Iterable[
  dotty1$collections$immutable$Iter2$Seq$$AA
], dotty1.collections.immutable.Iter2.FromIterator[[hk$0] =>
  dotty1.collections.immutable.Iter2.Seq[hk$0]
] --> Object, Object
completing class Seq, parents = List(AppliedTypeTree(Ident(Iterable),List(Ident(AA))), AppliedTypeTree(Ident(FromIterator),List(Ident(Seq)))), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Iterable), dotty1$collections$immutable$Iter2$Iterable$$IA, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Seq)),dotty1$collections$immutable$Iter2$Seq$$AA)) | 218534188), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),FromIterator), dotty1$collections$immutable$Iter2$FromIterator$$C, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(NoPrefix,scala)),Lambda$I), $apply, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Seq), dotty1$collections$immutable$Iter2$Seq$$AA, TypeAlias(TypeRef(RefinedThis(173044214),hk$0)) | 2088146463)) | 173044214)) | 1065324281)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Iterable), TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),FromIterator))
Expansion: def apply(i: Int): AA expands to def apply(i: Int): AA
Expansion: def length: Int expands to def length: Int
creating symbol for def apply(i: Int): AA in Mode(ImplicitsEnabled)
entered: method apply in class Seq and Scopes(type dotty1$collections$immutable$Iter2$Seq$$AA, type AA, method <init>, type dotty1$collections$immutable$Iter2$Iterable$$IA, type dotty1$collections$immutable$Iter2$FromIterator$$C)
creating symbol for def length: Int in Mode(ImplicitsEnabled)
entered: method length in class Seq and Scopes(type dotty1$collections$immutable$Iter2$Seq$$AA, type AA, method <init>, type dotty1$collections$immutable$Iter2$Iterable$$IA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method apply)
typed ident type X in type C
Expansion: c: Seq[SA] & FromIterator[C] expands to c: Seq[SA] & FromIterator[C]
creating symbol for c: Seq[SA] & FromIterator[C] in Mode(ImplicitsEnabled)
entered: val c in method SeqTransforms and Scopes(type SA, type C)
typed ident type Seq in val c
typed ident type SA in val c
typed ident type FromIterator in val c
typed ident type C in val c
typed ident type SA in method SeqTransforms
typed ident type C in method SeqTransforms
Expansion: def <init>[SA, C[X] <: dotty1.collections.immutable.Iter2.Seq[X]](
  c:
    dotty1.collections.immutable.Iter2.Seq[SA] &
      dotty1.collections.immutable.Iter2.FromIterator[C]
) expands to def <init>[SA, C[X] <: dotty1.collections.immutable.Iter2.Seq[X]](
  c:
    dotty1.collections.immutable.Iter2.Seq[SA] &
      dotty1.collections.immutable.Iter2.FromIterator[C]
)
creating symbol for def <init>[SA, C[X] <: dotty1.collections.immutable.Iter2.Seq[X]](
  c:
    dotty1.collections.immutable.Iter2.Seq[SA] &
      dotty1.collections.immutable.Iter2.FromIterator[C]
) in Mode(ImplicitsEnabled)
entered: method <init> in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA, type SA, type dotty1$collections$immutable$Iter2$SeqTransforms$$C, type C, val c)
Expansion: SA expands to SA
Expansion: C[X] <: dotty1.collections.immutable.Iter2.Seq[X] expands to C[X] <: dotty1.collections.immutable.Iter2.Seq[X]
creating symbol for SA in Mode(ImplicitsEnabled)
entered: type SA in method <init> and Scopes()
creating symbol for C[X] <: dotty1.collections.immutable.Iter2.Seq[X] in Mode(ImplicitsEnabled)
entered: type C in method <init> and Scopes(type SA)
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type C and Scopes()
typed ident type Seq in type C
typed ident type X in type C
Expansion: c:
  dotty1.collections.immutable.Iter2.Seq[SA] &
    dotty1.collections.immutable.Iter2.FromIterator[C] expands to c:
  dotty1.collections.immutable.Iter2.Seq[SA] &
    dotty1.collections.immutable.Iter2.FromIterator[C]
creating symbol for c:
  dotty1.collections.immutable.Iter2.Seq[SA] &
    dotty1.collections.immutable.Iter2.FromIterator[C] in Mode(ImplicitsEnabled)
entered: val c in method <init> and Scopes(type SA, type C)
typed ident type Seq in val c
typed ident type SA in val c
typed ident type FromIterator in val c
typed ident type C in val c
typed ident type AnyVal in method <init>
completing class SeqTransforms, parents = List(Ident(AnyVal)), parentTypes = List(TypeRef(TermRef(ThisType(TypeRef(NoPrefix,<root>)),scala),AnyVal)), parentRefs = List(TypeRef(TermRef(ThisType(TypeRef(NoPrefix,<root>)),scala),AnyVal))
Expansion: def reverse: C[SA] = {
  val elems = new Array[AnyRef](c.length)
  var i = elems.length
  val it = c.iterator
  while (it.hasNext) do {
    i -= 1
    elems(i) = it.next.asInstanceOf[AnyRef]
  }
  val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
  xzz
} expands to def reverse: C[SA] = {
  val elems = new Array[AnyRef](c.length)
  var i = elems.length
  val it = c.iterator
  while (it.hasNext) do {
    i -= 1
    elems(i) = it.next.asInstanceOf[AnyRef]
  }
  val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
  xzz
}
Expansion: def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p) expands to def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
creating symbol for def reverse: C[SA] = {
  val elems = new Array[AnyRef](c.length)
  var i = elems.length
  val it = c.iterator
  while (it.hasNext) do {
    i -= 1
    elems(i) = it.next.asInstanceOf[AnyRef]
  }
  val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
  xzz
} in Mode(ImplicitsEnabled)
entered: method reverse in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA, type SA, type dotty1$collections$immutable$Iter2$SeqTransforms$$C, type C, val c, method <init>)
creating symbol for def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p) in Mode(ImplicitsEnabled)
entered: method indexWhere in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA, type SA, type dotty1$collections$immutable$Iter2$SeqTransforms$$C, type C, val c, method <init>, method reverse)
typed ident type dotty1$collections$immutable$Iter2$SeqTransforms$$SA in type SA
typed ident type dotty1$collections$immutable$Iter2$SeqTransforms$$C in type C
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type dotty1$collections$immutable$Iter2$SeqTransforms$$C and Scopes()
>>>> StoredError: += is not a member of Int
typed ident i in method while$
adapt overloaded <overloaded Int#+> with alternatives (x: Double)Double, (x: Float)Float, (x: Long)Long, (x: Int)Int, (x: Char)Int, (x: Short)Int, (x: Byte)Int, (x: String)String
typed ident while$ in method while$
typed ident while$ in method indexWhere
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method zip and Scopes()
Expansion: that: Iterator[B] expands to that: Iterator[B]
creating symbol for that: Iterator[B] in Mode(ImplicitsEnabled)
entered: val that in method zip and Scopes(type B)
typed ident type Iterator in val that
typed ident type B in val that
typed ident type Iterator in method zip
typed ident type A in method zip
typed ident type B in method zip
typed ident $qmark$qmark$qmark in method zip
check no double defs trait Iterator
ensure first is class  -->
typed ident type Iterator in method buildIterator
typed ident type A in method buildIterator
typed ident iterator in method buildIterator
check no double defs trait IterableOnce
ensure first is class  -->
typed ident type dotty1$collections$immutable$Iter2$FromIterator$$C in type C
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method fromIterator and Scopes()
Expansion: it: Iterator[B] expands to it: Iterator[B]
creating symbol for it: Iterator[B] in Mode(ImplicitsEnabled)
entered: val it in method fromIterator and Scopes(type B)
typed ident type Iterator in val it
typed ident type B in val it
typed ident type C in method fromIterator
typed ident type B in method fromIterator
check no double defs trait FromIterator
ensure first is class dotty1.collections.immutable.Iter2.IterableOnce[
  dotty1$collections$immutable$Iter2$Iterable$$IA
], dotty1.collections.immutable.Iter2.FromIterator[
  dotty1.collections.immutable.Iter2.Iterable
] --> Object, Object
check no double defs trait Iterable
ensure first is class dotty1.collections.immutable.Iter2.Iterable[
  dotty1$collections$immutable$Iter2$Seq$$AA
], dotty1.collections.immutable.Iter2.FromIterator[[hk$0] =>
  dotty1.collections.immutable.Iter2.Seq[hk$0]
] --> Object, Object
Expansion: i: Int expands to i: Int
creating symbol for i: Int in Mode(ImplicitsEnabled)
entered: val i in method apply and Scopes()
typed ident type Int in val i
typed ident type AA in method apply
typed ident type Int in method length
check no double defs trait Seq
Expansion: def <init>[A]() expands to def <init>[A]()
creating symbol for def <init>[A]() in Mode(ImplicitsEnabled)
entered: method <init> in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
typed ident type Seq in method <init>
typed ident type A in method <init>
typed ident type dotty1$collections$immutable$Iter2$List$$A in type A
typed ident type FromIterator in method <init>
typed ident type List in method <init>
ensure first is class dotty1.collections.immutable.Iter2.Seq[
  dotty1$collections$immutable$Iter2$List$$A
], dotty1.collections.immutable.Iter2.FromIterator[[hk$0] =>
  dotty1.collections.immutable.Iter2.List[hk$0]
] --> Object, Object
completing class List, parents = List(AppliedTypeTree(Ident(Seq),List(Ident(A))), AppliedTypeTree(Ident(FromIterator),List(Ident(List)))), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Seq), dotty1$collections$immutable$Iter2$Seq$$AA, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),List)),dotty1$collections$immutable$Iter2$List$$A)) | 341047306), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),FromIterator), dotty1$collections$immutable$Iter2$FromIterator$$C, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(NoPrefix,scala)),Lambda$I), $apply, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),List), dotty1$collections$immutable$Iter2$List$$A, TypeAlias(TypeRef(RefinedThis(-271779394),hk$0)) | -1455890599)) | -271779394)) | 1533370716)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Seq), TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),FromIterator))
Expansion: def isEmpty: Boolean expands to def isEmpty: Boolean
Expansion: def head: A expands to def head: A
Expansion: def tail: List[A] expands to def tail: List[A]
Expansion: def iterator = new ListIterator[A](this) expands to def iterator = new ListIterator[A](this)
Expansion: def fromIterator[B](it: Iterator[B]): List[B] =
  it match {
    case ListIterator(xs) =>
      xs
    case _ =>
      if (it.hasNext) Cons(it.next, fromIterator(it)) else
        Nil.asInstanceOf[List[B]]
  } expands to def fromIterator[B](it: Iterator[B]): List[B] =
  it match {
    case ListIterator(xs) =>
      xs
    case _ =>
      if (it.hasNext) Cons(it.next, fromIterator(it)) else
        Nil.asInstanceOf[List[B]]
  }
Expansion: def apply(i: Int): A = {
  require(! isEmpty)
  if (i == 0) head else tail.apply(i - 1)
} expands to def apply(i: Int): A = {
  require(! isEmpty)
  if (i == 0) head else tail.apply(i - 1)
}
Expansion: def length: Int = if (isEmpty) 0 else 1 + tail.length expands to def length: Int = if (isEmpty) 0 else 1 + tail.length
creating symbol for def isEmpty: Boolean in Mode(ImplicitsEnabled)
entered: method isEmpty in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C)
creating symbol for def head: A in Mode(ImplicitsEnabled)
entered: method head in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method isEmpty)
creating symbol for def tail: List[A] in Mode(ImplicitsEnabled)
entered: method tail in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method isEmpty, method head)
creating symbol for def iterator = new ListIterator[A](this) in Mode(ImplicitsEnabled)
entered: method iterator in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method isEmpty, method head, method tail)
creating symbol for def fromIterator[B](it: Iterator[B]): List[B] =
  it match {
    case ListIterator(xs) =>
      xs
    case _ =>
      if (it.hasNext) Cons(it.next, fromIterator(it)) else
        Nil.asInstanceOf[List[B]]
  } in Mode(ImplicitsEnabled)
entered: method fromIterator in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method isEmpty, method head, method tail, method iterator)
creating symbol for def apply(i: Int): A = {
  require(! isEmpty)
  if (i == 0) head else tail.apply(i - 1)
} in Mode(ImplicitsEnabled)
entered: method apply in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method isEmpty, method head, method tail, method iterator, method fromIterator)
creating symbol for def length: Int = if (isEmpty) 0 else 1 + tail.length in Mode(ImplicitsEnabled)
entered: method length in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method isEmpty, method head, method tail, method iterator, method fromIterator, method apply)
ensure first is class dotty1.collections.immutable.Iter2.Seq[
  dotty1$collections$immutable$Iter2$List$$A
], dotty1.collections.immutable.Iter2.FromIterator[[hk$0] =>
  dotty1.collections.immutable.Iter2.List[hk$0]
] --> Object, Object
typed ident type Boolean in method isEmpty
typed ident type A in method head
typed ident type List in method tail
typed ident type A in method tail
using inherited type for iterator; raw: =>
  dotty1.collections.immutable.Iter2.Iterator[
    dotty1$collections$immutable$Iter2$IterableOnce$$A
  ], inst: =>
  dotty1.collections.immutable.Iter2.Iterator[
    dotty1$collections$immutable$Iter2$IterableOnce$$A
  ], inherited: dotty1.collections.immutable.Iter2.Iterator[
  dotty1$collections$immutable$Iter2$List$$A
]
typed ident type ListIterator in method iterator
Expansion: def <init>[A](xs: List[A]) expands to def <init>[A](xs: List[A])
creating symbol for def <init>[A](xs: List[A]) in Mode(ImplicitsEnabled)
entered: method <init> in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
Expansion: xs: List[A] expands to xs: List[A]
creating symbol for xs: List[A] in Mode(ImplicitsEnabled)
entered: val xs in method <init> and Scopes(type A)
typed ident type List in val xs
typed ident type A in val xs
typed ident type Iterator in method <init>
typed ident type A in method <init>
typed ident type dotty1$collections$immutable$Iter2$ListIterator$$A in type A
typed ident type List in method <init>
typed ident type A in method <init>
ensure first is class dotty1.collections.immutable.Iter2.Iterator[
  dotty1$collections$immutable$Iter2$ListIterator$$A
], Product1[
  dotty1.collections.immutable.Iter2.List[
    dotty1$collections$immutable$Iter2$ListIterator$$A
  ]
] --> Object, <notype>
completing class ListIterator, parents = List(AppliedTypeTree(Ident(Iterator),List(Ident(A))), AppliedTypeTree(TypedSplice(TypeTree[TypeRef(ThisType(TypeRef(NoPrefix,scala)),Product1)]),List(AppliedTypeTree(Ident(List),List(Ident(A)))))), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Iterator), dotty1$collections$immutable$Iter2$Iterator$$A, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),ListIterator)),dotty1$collections$immutable$Iter2$ListIterator$$A)) | 53246108), RefinedType(TypeRef(ThisType(TypeRef(NoPrefix,scala)),Product1), scala$Product1$$T1, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),List), dotty1$collections$immutable$Iter2$List$$A, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),ListIterator)),dotty1$collections$immutable$Iter2$ListIterator$$A)) | -62648647)) | -1732540618)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Iterator), TypeRef(ThisType(TypeRef(NoPrefix,scala)),Product1))
Expansion: private[this] var current: List[A] = xs expands to private[this] var current: List[A] = xs
Expansion: def hasNext = ! current.isEmpty expands to def hasNext = ! current.isEmpty
Expansion: def next = {
  val res = current.head
  current = current.tail
  res
} expands to def next = {
  val res = current.head
  current = current.tail
  res
}
Expansion: def copy[A](xs = xs @scala.annotation.unchecked.uncheckedVariance()) =
  new
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >
  [...](...) expands to Thicket {
  def copy[A](xs) =
    new
      <derived typetree watching
        case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
          A
          val xs
          private[this] var current: ... = ...
          def hasNext = ...
          def next = ...
          def copy[...](...) = ...
          def isDefined = ...
          def _1 = ...
        }
      >
    [...](...)
  def copy$default$1[...] = ...
 }
Expansion: def isDefined = true expands to def isDefined = true
Expansion: def _1 = this.xs expands to def _1 = this.xs
creating symbol for private[this] var current: List[A] = xs in Mode(ImplicitsEnabled)
entered: val current in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1)
creating symbol for def hasNext = ! current.isEmpty in Mode(ImplicitsEnabled)
entered: method hasNext in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1, val current)
creating symbol for def next = {
  val res = current.head
  current = current.tail
  res
} in Mode(ImplicitsEnabled)
entered: method next in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1, val current, method hasNext)
creating symbol for def copy[A](xs) =
  new
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >
  [...](...) in Mode(ImplicitsEnabled)
entered: method copy in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1, val current, method hasNext, method next)
creating symbol for def copy$default$1[A] = xs @scala.annotation.unchecked.uncheckedVariance() in Mode(ImplicitsEnabled)
entered: method copy$default$1 in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1, val current, method hasNext, method next, method copy)
creating symbol for def isDefined = true in Mode(ImplicitsEnabled)
entered: method isDefined in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1, val current, method hasNext, method next, method copy, method copy$default$1)
creating symbol for def _1 = this.xs in Mode(ImplicitsEnabled)
entered: method _1 in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1, val current, method hasNext, method next, method copy, method copy$default$1, method isDefined)
typed ident type A in method iterator
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method fromIterator and Scopes()
Expansion: it: Iterator[B] expands to it: Iterator[B]
creating symbol for it: Iterator[B] in Mode(ImplicitsEnabled)
entered: val it in method fromIterator and Scopes(type B)
typed ident type Iterator in val it
typed ident type B in val it
typed ident type List in method fromIterator
typed ident type B in method fromIterator
typed ident it in method fromIterator
typed ident ListIterator in method fromIterator
Expansion: def <init>() expands to def <init>()
creating symbol for def <init>() in Mode(ImplicitsEnabled)
entered: method <init> in module class ListIterator$ and Scopes(method companion$class)
completing module class ListIterator$, parents = List(TypedSplice(TypeTree[TypeRef(ThisType(TypeRef(NoPrefix,scala)),AnyRef)])), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,scala)),AnyRef)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object))
Expansion: def apply[A](xs) =
  new
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >
  [...](...) expands to def apply[A](xs) =
  new
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >
  [...](...)
Expansion: def unapply[A](
  x$1:
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >[...]
) = x$1 expands to def unapply[A](
  x$1:
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >[...]
) = x$1
creating symbol for def apply[A](xs) =
  new
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >
  [...](...) in Mode(ImplicitsEnabled)
entered: method apply in module class ListIterator$ and Scopes(method companion$class, method <init>)
creating symbol for def unapply[A](
  x$1:
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >[...]
) = x$1 in Mode(ImplicitsEnabled)
entered: method unapply in module class ListIterator$ and Scopes(method companion$class, method <init>, method apply)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method unapply and Scopes()
Expansion: x$1:
  <derived typetree watching
    case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
      A
      val xs
      private[this] var current: ... = ...
      def hasNext = ...
      def next = ...
      def copy[...](...) = ...
      def isDefined = ...
      def _1 = ...
    }
  >[...] expands to x$1:
  <derived typetree watching
    case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
      A
      val xs
      private[this] var current: ... = ...
      def hasNext = ...
      def next = ...
      def copy[...](...) = ...
      def isDefined = ...
      def _1 = ...
    }
  >[...]
creating symbol for x$1:
  <derived typetree watching
    case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
      A
      val xs
      private[this] var current: ... = ...
      def hasNext = ...
      def next = ...
      def copy[...](...) = ...
      def isDefined = ...
      def _1 = ...
    }
  >[...] in Mode(ImplicitsEnabled)
entered: val x$1 in method unapply and Scopes(type A)
typed ident type A in val x$1
typed ident x$1 in method unapply
narrow gadt bound of type B: TypeBounds(TypeRef(ThisType(TypeRef(NoPrefix,scala)),Nothing), TypeRef(ThisType(TypeRef(NoPrefix,scala)),Any)) from above to TypeRef(ThisType(TypeRef(NoPrefix,scala)),Nothing) false
narrow gadt bound of type B: TypeBounds(TypeRef(ThisType(TypeRef(NoPrefix,scala)),Nothing), TypeRef(ThisType(TypeRef(NoPrefix,scala)),Any)) from below to TypeRef(ThisType(TypeRef(NoPrefix,scala)),Any) false
approx A, from below = false, bound = B, inst = B
instantiating (A? <: B) with B
using inherited type for _1; raw: => scala$Product1$$T1, inst: => scala$Product1$$T1, inherited: dotty1.collections.immutable.Iter2.List[
  dotty1$collections$immutable$Iter2$ListIterator$$A
]
typed ident xs in method fromIterator
typed ident _ in method fromIterator
typed bind xs @ _ pt = dotty1.collections.immutable.Iter2.List[B] bodytpe = dotty1.collections.immutable.Iter2.List[B]
typed ident xs in method fromIterator
typed ident _ in method fromIterator
typed ident it in method fromIterator
typed ident Cons in method fromIterator
Expansion: def <init>() expands to def <init>()
creating symbol for def <init>() in Mode(ImplicitsEnabled)
entered: method <init> in module class Cons$ and Scopes(method companion$class)
completing module class Cons$, parents = List(TypedSplice(TypeTree[TypeRef(ThisType(TypeRef(NoPrefix,scala)),AnyRef)])), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,scala)),AnyRef)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object))
Expansion: def apply[A](x, xs) =
  new
    <derived typetree watching
      case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[..., ...]

{
        A
        val x
        val xs
        def isEmpty = ...
        def head = ...
        def tail = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >
  [...](..., ...) expands to def apply[A](x, xs) =
  new
    <derived typetree watching
      case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[..., ...]

{
        A
        val x
        val xs
        def isEmpty = ...
        def head = ...
        def tail = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >
  [...](..., ...)
Expansion: def unapply[A](
  x$1:
    <derived typetree watching
      case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[..., ...]

{
        A
        val x
        val xs
        def isEmpty = ...
        def head = ...
        def tail = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >[...]
) = x$1 expands to def unapply[A](
  x$1:
    <derived typetree watching
      case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[..., ...]

{
        A
        val x
        val xs
        def isEmpty = ...
        def head = ...
        def tail = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >[...]
) = x$1
creating symbol for def apply[A](x, xs) =
  new
    <derived typetree watching
      case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[..., ...]

{
        A
        val x
        val xs
        def isEmpty = ...
        def head = ...
        def tail = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >
  [...](..., ...) in Mode(ImplicitsEnabled)
entered: method apply in module class Cons$ and Scopes(method companion$class, method <init>)
creating symbol for def unapply[A](
  x$1:
    <derived typetree watching
      case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[..., ...]

{
        A
        val x
        val xs
        def isEmpty = ...
        def head = ...
        def tail = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >[...]
) = x$1 in Mode(ImplicitsEnabled)
entered: method unapply in module class Cons$ and Scopes(method companion$class, method <init>, method apply)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method apply and Scopes()
Expansion: def <init>[A](x: A, xs: List[A]) expands to def <init>[A](x: A, xs: List[A])
creating symbol for def <init>[A](x: A, xs: List[A]) in Mode(ImplicitsEnabled)
entered: method <init> in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A, val x, val xs, method companion$module)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
Expansion: x: A expands to x: A
Expansion: xs: List[A] expands to xs: List[A]
creating symbol for x: A in Mode(ImplicitsEnabled)
entered: val x in method <init> and Scopes(type A)
creating symbol for xs: List[A] in Mode(ImplicitsEnabled)
entered: val xs in method <init> and Scopes(type A, val x)
typed ident type A in val x
typed ident type List in val xs
typed ident type A in val xs
typed ident type List in method <init>
typed ident type A in method <init>
typed ident type dotty1$collections$immutable$Iter2$Cons$$A in type A
typed ident type A in method <init>
typed ident type List in method <init>
typed ident type A in method <init>
ensure first is class dotty1.collections.immutable.Iter2.List[
  dotty1$collections$immutable$Iter2$Cons$$A
], Product2[dotty1$collections$immutable$Iter2$Cons$$A,
  dotty1.collections.immutable.Iter2.List[
    dotty1$collections$immutable$Iter2$Cons$$A
  ]
] --> Object, <notype>
completing class Cons, parents = List(AppliedTypeTree(Ident(List),List(Ident(A))), AppliedTypeTree(TypedSplice(TypeTree[TypeRef(ThisType(TypeRef(NoPrefix,scala)),Product2)]),List(Ident(A), AppliedTypeTree(Ident(List),List(Ident(A)))))), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),List), dotty1$collections$immutable$Iter2$List$$A, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Cons)),dotty1$collections$immutable$Iter2$Cons$$A)) | 494348141), RefinedType(RefinedType(TypeRef(ThisType(TypeRef(NoPrefix,scala)),Product2), scala$Product2$$T1, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Cons)),dotty1$collections$immutable$Iter2$Cons$$A)) | 400837376), scala$Product2$$T2, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),List), dotty1$collections$immutable$Iter2$List$$A, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Cons)),dotty1$collections$immutable$Iter2$Cons$$A)) | 494348141)) | -1265191348)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),List), TypeRef(ThisType(TypeRef(NoPrefix,scala)),Product2))
Expansion: def isEmpty = false expands to def isEmpty = false
Expansion: def head = x expands to def head = x
Expansion: def tail = xs expands to def tail = xs
Expansion: def copy[A](x = x @scala.annotation.unchecked.uncheckedVariance(),
  xs = xs @scala.annotation.unchecked.uncheckedVariance()
) =
  new
    <derived typetree watching
      case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[..., ...]

{
        A
        val x
        val xs
        def isEmpty = ...
        def head = ...
        def tail = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >
  [...](..., ...) expands to Thicket {
  def copy[A](x, xs) =
    new
      <derived typetree watching
        case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[...,
          ...
        ] {
          A
          val x
          val xs
          def isEmpty = ...
          def head = ...
          def tail = ...
          def copy[...](..., ...) = ...
          def isDefined = ...
          def _1 = ...
          def _2 = ...
        }
      >
    [...](..., ...)
  def copy$default$1[...] = ...
  def copy$default$2[...] = ...
 }
Expansion: def isDefined = true expands to def isDefined = true
Expansion: def _1 = this.x expands to def _1 = this.x
Expansion: def _2 = this.xs expands to def _2 = this.xs
creating symbol for def isEmpty = false in Mode(ImplicitsEnabled)
entered: method isEmpty in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A, val x, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$List$$A, type scala$Product2$$T2, type scala$Product2$$T1)
creating symbol for def head = x in Mode(ImplicitsEnabled)
entered: method head in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A, val x, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$List$$A, type scala$Product2$$T2, type scala$Product2$$T1, method isEmpty)
creating symbol for def tail = xs in Mode(ImplicitsEnabled)
entered: method tail in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A, val x, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$List$$A, type scala$Product2$$T2, type scala$Product2$$T1, method isEmpty, method head)
creating symbol for def copy[A](x, xs) =
  new
    <derived typetree watching
      case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[..., ...]

A
      val x
      val xs
      def isEmpty: ... = ...
      def head: ... = ...
      def tail: ... = ...
      def copy[...](..., ...): ... = ...
      def isDefined: ... = ...
      def _1: ... = ...
      def _2: ... = ...
    }
  >[...] expands to x$1:
  <derived typetree watching
    case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[..., ...] {

A
      val x
      val xs
      def isEmpty: ... = ...
      def head: ... = ...
      def tail: ... = ...
      def copy[...](..., ...): ... = ...
      def isDefined: ... = ...
      def _1: ... = ...
      def _2: ... = ...
    }
  >[...]
creating symbol for x$1:
  <derived typetree watching
    case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[..., ...] {

A
      val x
      val xs
      def isEmpty: ... = ...
      def head: ... = ...
      def tail: ... = ...
      def copy[...](..., ...): ... = ...
      def isDefined: ... = ...
      def _1: ... = ...
      def _2: ... = ...
    }
  >[...] in Mode(ImplicitsEnabled)
entered: val x$1 in method unapply and Scopes(type A)
typed ident type A in val x$1
typed ident x$1 in method unapply
check no double defs object Cons$
typed ident type Nil$ in module Nil
typed ident type Nil$ in module Nil
ensure first is class dotty1.collections.immutable.Iter2.List[Nothing] --> Object
typed ident Nil in module class Iter2$
using inherited type for isEmpty; raw: => Boolean, inst: => Boolean, inherited: Boolean
using inherited type for head; raw: => dotty1$collections$immutable$Iter2$List$$A, inst: => dotty1$collections$immutable$Iter2$List$$A, inherited: Nothing
typed ident $qmark$qmark$qmark in method head
using inherited type for tail; raw: =>
  dotty1.collections.immutable.Iter2.List[
    dotty1$collections$immutable$Iter2$List$$A
  ], inst: =>
  dotty1.collections.immutable.Iter2.List[
    dotty1$collections$immutable$Iter2$List$$A
  ], inherited: dotty1.collections.immutable.Iter2.List[Nothing]
typed ident $qmark$qmark$qmark in method tail
check no double defs object Nil$
Expansion: private def <init>[A](initElems: Array[AnyRef], initLen: Int) expands to private def <init>[A](initElems: Array[AnyRef], initLen: Int)
creating symbol for private def <init>[A](initElems: Array[AnyRef], initLen: Int) in Mode(ImplicitsEnabled)
entered: method <init> in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems, val initLen)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
Expansion: initElems: Array[AnyRef] expands to initElems: Array[AnyRef]
Expansion: initLen: Int expands to initLen: Int
creating symbol for initElems: Array[AnyRef] in Mode(ImplicitsEnabled)
entered: val initElems in method <init> and Scopes(type A)
creating symbol for initLen: Int in Mode(ImplicitsEnabled)
entered: val initLen in method <init> and Scopes(type A, val initElems)
typed ident type Array in val initElems
typed ident type AnyRef in val initElems
typed ident type Int in val initLen
typed ident type Seq in method <init>
typed ident type A in method <init>
typed ident type dotty1$collections$immutable$Iter2$ArrayBuffer$$A in type A
typed ident type FromIterator in method <init>
typed ident type ArrayBuffer in method <init>
ensure first is class dotty1.collections.immutable.Iter2.Seq[
  dotty1$collections$immutable$Iter2$ArrayBuffer$$A
], dotty1.collections.immutable.Iter2.FromIterator[[hk$0] =>
  dotty1.collections.immutable.Iter2.ArrayBuffer[hk$0]
] --> Object, Object
completing class ArrayBuffer, parents = List(AppliedTypeTree(Ident(Seq),List(Ident(A))), AppliedTypeTree(Ident(FromIterator),List(Ident(ArrayBuffer)))), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Seq), dotty1$collections$immutable$Iter2$Seq$$AA, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),ArrayBuffer)),dotty1$collections$immutable$Iter2$ArrayBuffer$$A)) | 2091893354), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),FromIterator), dotty1$collections$immutable$Iter2$FromIterator$$C, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(NoPrefix,scala)),Lambda$I), $apply, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),ArrayBuffer), dotty1$collections$immutable$Iter2$ArrayBuffer$$A, TypeAlias(TypeRef(RefinedThis(764635201),hk$0)) | -671920714)) | 764635201)) | -1675678925)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Seq), TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),FromIterator))
Expansion: def <init>[A]() = {
  <init>(new Array[AnyRef](16), 0)
  ()
} expands to def <init>[A]() = {
  <init>(new Array[AnyRef](16), 0)
  ()
}
Expansion: def <init>[A](it: ArrayIterator[A]) = {
  <init>(it.elems, it.len)
  ()
} expands to def <init>[A](it: ArrayIterator[A]) = {
  <init>(it.elems, it.len)
  ()
}
Expansion: private var elems: Array[AnyRef] = initElems expands to Thicket {
  private var elems: Array[AnyRef] = initElems
  private <accessor> def elems_=(x$1): Unit = ()
 }
Expansion: private var len = 0 expands to Thicket {
  private var len = 0
  private <accessor> def len_=(x$1): Unit = ()
 }
Expansion: def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]] expands to def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
Expansion: override def buildIterator =
  new ArrayIterator(elems, len).asInstanceOf[Iterator[A]] expands to override def buildIterator =
  new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
Expansion: def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
  new ArrayBuffer(ArrayIterator.fromIterator(it)) expands to def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
  new ArrayBuffer(ArrayIterator.fromIterator(it))
Expansion: def apply(i: Int) = elems(i).asInstanceOf[A] expands to def apply(i: Int) = elems(i).asInstanceOf[A]
Expansion: def length = len expands to def length = len
creating symbol for def <init>[A]() = {
  <init>(new Array[AnyRef](16), 0)
  ()
} in Mode(ImplicitsEnabled)
entered: method <init> in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems, val initLen, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C)
creating symbol for def <init>[A](it: ArrayIterator[A]) = {
  <init>(it.elems, it.len)
  ()
} in Mode(ImplicitsEnabled)
entered: method <init> in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems, val initLen, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method <init>)
creating symbol for private var elems: Array[AnyRef] = initElems in Mode(ImplicitsEnabled)
entered: val elems in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems, val initLen, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method <init>, method <init>)
creating symbol for private <accessor> def elems_=(x$1): Unit = () in Mode(ImplicitsEnabled)
entered: method elems_$eq in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems, val initLen, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method <init>, method <init>, val elems)
creating symbol for private var len = 0 in Mode(ImplicitsEnabled)
entered: val len in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems, val initLen, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method <init>, method <init>, val elems, method elems_$eq)
creating symbol for private <accessor> def len_=(x$1): Unit = () in Mode(ImplicitsEnabled)
entered: method len_$eq in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems, val initLen, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method <init>, method <init>, val elems, method elems_$eq, val len)
creating symbol for def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]] in Mode(ImplicitsEnabled)
entered: method iterator in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems, val initLen, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method <init>, method <init>, val elems, method elems_$eq, val len, method len_$eq)
creating symbol for override def buildIterator =
  new ArrayIterator(elems, len).asInstanceOf[Iterator[A]] in Mode(ImplicitsEnabled)
entered: method buildIterator in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems, val initLen, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method <init>, method <init>, val elems, method elems_$eq, val len, method len_$eq, method iterator)
creating symbol for def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
  new ArrayBuffer(ArrayIterator.fromIterator(it)) in Mode(ImplicitsEnabled)
entered: method fromIterator in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems, val initLen, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method <init>, method <init>, val elems, method elems_$eq, val len, method len_$eq, method iterator, method buildIterator)
creating symbol for def apply(i: Int) = elems(i).asInstanceOf[A] in Mode(ImplicitsEnabled)
entered: method apply in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems, val initLen, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method <init>, method <init>, val elems, method elems_$eq, val len, method len_$eq, method iterator, method buildIterator, method fromIterator)
creating symbol for def length = len in Mode(ImplicitsEnabled)
entered: method length in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems, val initLen, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method <init>, method <init>, val elems, method elems_$eq, val len, method len_$eq, method iterator, method buildIterator, method fromIterator, method apply)
ensure first is class dotty1.collections.immutable.Iter2.Seq[
  dotty1$collections$immutable$Iter2$ArrayBuffer$$A
], dotty1.collections.immutable.Iter2.FromIterator[[hk$0] =>
  dotty1.collections.immutable.Iter2.ArrayBuffer[hk$0]
] --> Object, Object
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
typed ident <init> in method <init>
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
Expansion: it: ArrayIterator[A] expands to it: ArrayIterator[A]
creating symbol for it: ArrayIterator[A] in Mode(ImplicitsEnabled)
entered: val it in method <init> and Scopes(type A)
typed ident type ArrayIterator in val it
Expansion: def <init>[A](elems: Array[AnyRef], len: Int) expands to def <init>[A](elems: Array[AnyRef], len: Int)
creating symbol for def <init>[A](elems: Array[AnyRef], len: Int) in Mode(ImplicitsEnabled)
entered: method <init> in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
Expansion: elems: Array[AnyRef] expands to elems: Array[AnyRef]
Expansion: len: Int expands to len: Int
creating symbol for elems: Array[AnyRef] in Mode(ImplicitsEnabled)
entered: val elems in method <init> and Scopes(type A)
creating symbol for len: Int in Mode(ImplicitsEnabled)
entered: val len in method <init> and Scopes(type A, val elems)
typed ident type Array in val elems
typed ident type AnyRef in val elems
typed ident type Int in val len
typed ident type Iterator in method <init>
typed ident type A in method <init>
typed ident type dotty1$collections$immutable$Iter2$ArrayIterator$$A in type A
typed ident type Array in method <init>
typed ident type AnyRef in method <init>
typed ident type Int in method <init>
ensure first is class dotty1.collections.immutable.Iter2.Iterator[
  dotty1$collections$immutable$Iter2$ArrayIterator$$A
], Product2[Array[AnyRef], Int] --> Object, <notype>
completing class ArrayIterator, parents = List(AppliedTypeTree(Ident(Iterator),List(Ident(A))), AppliedTypeTree(TypedSplice(TypeTree[TypeRef(ThisType(TypeRef(NoPrefix,scala)),Product2)]),List(AppliedTypeTree(Ident(Array),List(Ident(AnyRef))), Ident(Int)))), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Iterator), dotty1$collections$immutable$Iter2$Iterator$$A, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),ArrayIterator)),dotty1$collections$immutable$Iter2$ArrayIterator$$A)) | -1238074281), RefinedType(RefinedType(TypeRef(ThisType(TypeRef(NoPrefix,scala)),Product2), scala$Product2$$T1, TypeAlias(RefinedType(TypeRef(TermRef(ThisType(TypeRef(NoPrefix,<root>)),scala),Array), scala$Array$$T, TypeAlias(TypeRef(TermRef(ThisType(TypeRef(NoPrefix,<root>)),scala),AnyRef)) | 140698194)) | 195344344), scala$Product2$$T2, TypeAlias(TypeRef(TermRef(ThisType(TypeRef(NoPrefix,<root>)),scala),Int)) | 2023554133)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,immutable)),Iter2$)),Iterator), TypeRef(ThisType(TypeRef(NoPrefix,scala)),Product2))
Expansion: private def elem(i: Int) = elems(i).asInstanceOf[A] expands to private def elem(i: Int) = elems(i).asInstanceOf[A]
Expansion: private var cur = 0 expands to Thicket {
  private var cur = 0
  private <accessor> def cur_=(x$1): Unit = ()
 }
Expansion: def hasNext = cur < len expands to def hasNext = cur < len
Expansion: def next = {
  val res = elem(cur)
  cur += 1
  res
} expands to def next = {
  val res = elem(cur)
  cur += 1
  res
}
Expansion: override def foreach(f: (A) => Unit): Unit = for i <- 0 until len do f(elem(i)) expands to override def foreach(f: (A) => Unit): Unit = for i <- 0 until len do f(elem(i))
Expansion: override def map[B](f: (A) => B): ArrayIterator[B] = {
  var mapped = elems
  for i <- 0 until len do {
    val x = elem(i)
    val y = widen(f(x))
    if (widen(x) ne y) {
      if (mapped eq elems) mapped = new Array[AnyRef](len)
      mapped(i) = y
    }
  }
  if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
    new ArrayIterator(mapped, len)
} expands to override def map[B](f: (A) => B): ArrayIterator[B] = {
  var mapped = elems
  for i <- 0 until len do {
    val x = elem(i)
    val y = widen(f(x))
    if (widen(x) ne y) {
      if (mapped eq elems) mapped = new Array[AnyRef](len)
      mapped(i) = y
    }
  }
  if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
    new ArrayIterator(mapped, len)
}
Expansion: override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
  flatten(map(_$2 => f(_$2).buildIterator)) expands to override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
  flatten(map(_$2 => f(_$2).buildIterator))
Expansion: override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
  val thatIterator @ ArrayIterator(elems2, len2) = fromIterator(that.iterator)
  if (len == 0) thatIterator else
    if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
      val resLen = len + len2
      val resElems = new Array[AnyRef](resLen)
      Array.copy(elems, 0, resElems, 0, len)
      Array.copy(elems2, 0, resElems, len, len2)
      new ArrayIterator(resElems, resLen)
    }
} expands to override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
  val thatIterator @ ArrayIterator(elems2, len2) = fromIterator(that.iterator)
  if (len == 0) thatIterator else
    if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
      val resLen = len + len2
      val resElems = new Array[AnyRef](resLen)
      Array.copy(elems, 0, resElems, 0, len)
      Array.copy(elems2, 0, resElems, len, len2)
      new ArrayIterator(resElems, resLen)
    }
}
Expansion: def copy[A](elems = elems @scala.annotation.unchecked.uncheckedVariance(),
  len = len @scala.annotation.unchecked.uncheckedVariance()
) =
  new
    <derived typetree watching
      case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
         with
      ...[..., ...] {
        A
        val elems
        val len
        import ...._
        private def elem(...) = ...
        private var cur = ...
        def hasNext = ...
        def next = ...
        override def foreach(...): ... = ...
        override def map[...](...): ... = ...
        override def flatMap[...](...): ... = ...
        override def ++[...](...): ... = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >
  [...](..., ...) expands to Thicket {
  def copy[A](elems, len) =
    new
      <derived typetree watching
        case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
           with
        ...[..., ...] {
          A
          val elems
          val len
          import ...._
          private def elem(...) = ...
          private var cur = ...
          def hasNext = ...
          def next = ...
          override def foreach(...): ... = ...
          override def map[...](...): ... = ...
          override def flatMap[...](...): ... = ...
          override def ++[...](...): ... = ...
          def copy[...](..., ...) = ...
          def isDefined = ...
          def _1 = ...
          def _2 = ...
        }
      >
    [...](..., ...)
  def copy$default$1[...] = ...
  def copy$default$2[...] = ...
 }
Expansion: def isDefined = true expands to def isDefined = true
Expansion: def _1 = this.elems expands to def _1 = this.elems
Expansion: def _2 = this.len expands to def _2 = this.len
creating symbol for import ArrayIterator._ in Mode(ImplicitsEnabled)
creating symbol for private def elem(i: Int) = elems(i).asInstanceOf[A] in Mode(ImplicitsEnabled)
entered: method elem in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1)
creating symbol for private var cur = 0 in Mode(ImplicitsEnabled)
entered: val cur in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem)
creating symbol for private <accessor> def cur_=(x$1): Unit = () in Mode(ImplicitsEnabled)
entered: method cur_$eq in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem, val cur)
creating symbol for def hasNext = cur < len in Mode(ImplicitsEnabled)
entered: method hasNext in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem, val cur, method cur_$eq)
creating symbol for def next = {
  val res = elem(cur)
  cur += 1
  res
} in Mode(ImplicitsEnabled)
entered: method next in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem, val cur, method cur_$eq, method hasNext)
creating symbol for override def foreach(f: (A) => Unit): Unit = for i <- 0 until len do f(elem(i)) in Mode(ImplicitsEnabled)
entered: method foreach in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem, val cur, method cur_$eq, method hasNext, method next)
creating symbol for override def map[B](f: (A) => B): ArrayIterator[B] = {
  var mapped = elems
  for i <- 0 until len do {
    val x = elem(i)
    val y = widen(f(x))
    if (widen(x) ne y) {
      if (mapped eq elems) mapped = new Array[AnyRef](len)
      mapped(i) = y
    }
  }
  if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
    new ArrayIterator(mapped, len)
} in Mode(ImplicitsEnabled)
entered: method map in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem, val cur, method cur_$eq, method hasNext, method next, method foreach)
creating symbol for override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
  flatten(map(_$2 => f(_$2).buildIterator)) in Mode(ImplicitsEnabled)
entered: method flatMap in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem, val cur, method cur_$eq, method hasNext, method next, method foreach, method map)
creating symbol for override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
  val thatIterator @ ArrayIterator(elems2, len2) = fromIterator(that.iterator)
  if (len == 0) thatIterator else
    if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
      val resLen = len + len2
      val resElems = new Array[AnyRef](resLen)
      Array.copy(elems, 0, resElems, 0, len)
      Array.copy(elems2, 0, resElems, len, len2)
      new ArrayIterator(resElems, resLen)
    }
} in Mode(ImplicitsEnabled)
entered: method $plus$plus in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem, val cur, method cur_$eq, method hasNext, method next, method foreach, method map, method flatMap)
creating symbol for def copy[A](elems, len) =
  new
    <derived typetree watching
      case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
         with
      ...[..., ...] {
        A
        val elems
        val len
        import ...._
        private def elem(...) = ...
        private var cur = ...
        def hasNext = ...
        def next = ...
        override def foreach(...): ... = ...
        override def map[...](...): ... = ...
        override def flatMap[...](...): ... = ...
        override def ++[...](...): ... = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >
  [...](..., ...) in Mode(ImplicitsEnabled)
entered: method copy in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem, val cur, method cur_$eq, method hasNext, method next, method foreach, method map, method flatMap, method $plus$plus)
creating symbol for def copy$default$1[A] = elems @scala.annotation.unchecked.uncheckedVariance() in Mode(ImplicitsEnabled)
entered: method copy$default$1 in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem, val cur, method cur_$eq, method hasNext, method next, method foreach, method map, method flatMap, method $plus$plus, method copy)
creating symbol for def copy$default$2[A] = len @scala.annotation.unchecked.uncheckedVariance() in Mode(ImplicitsEnabled)
entered: method copy$default$2 in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem, val cur, method cur_$eq, method hasNext, method next, method foreach, method map, method flatMap, method $plus$plus, method copy, method copy$default$1)
creating symbol for def isDefined = true in Mode(ImplicitsEnabled)
entered: method isDefined in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem, val cur, method cur_$eq, method hasNext, method next, method foreach, method map, method flatMap, method $plus$plus, method copy, method copy$default$1, method copy$default$2)
creating symbol for def _1 = this.elems in Mode(ImplicitsEnabled)
entered: method _1 in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem, val cur, method cur_$eq, method hasNext, method next, method foreach, method map, method flatMap, method $plus$plus, method copy, method copy$default$1, method copy$default$2, method isDefined)
creating symbol for def _2 = this.len in Mode(ImplicitsEnabled)
entered: method _2 in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems, val len, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product2$$T2, type scala$Product2$$T1, method elem, val cur, method cur_$eq, method hasNext, method next, method foreach, method map, method flatMap, method $plus$plus, method copy, method copy$default$1, method copy$default$2, method isDefined, method _1)
typed ident type A in val it
adapt overloaded <overloaded ArrayBuffer.this.<init>> with alternatives [A]
  (initElems: Array[AnyRef], initLen: Int)
    dotty1.collections.immutable.Iter2.ArrayBuffer[A], [A]
  (it: dotty1.collections.immutable.Iter2.ArrayIterator[A])
    dotty1.collections.immutable.Iter2.ArrayBuffer[A], [A]()dotty1.collections.immutable.Iter2.ArrayBuffer[A]
typed ident type Array in method <init>
typed ident type AnyRef in method <init>
instantiating non-occurring (A?) in Unit
approx A, from below = true, bound = Nothing, inst = Nothing
instantiating (A?) with Nothing
typed ident <init> in method <init>
adapt overloaded <overloaded ArrayBuffer.this.<init>> with alternatives [A]
  (initElems: Array[AnyRef], initLen: Int)
    dotty1.collections.immutable.Iter2.ArrayBuffer[A], [A]
  (it: dotty1.collections.immutable.Iter2.ArrayIterator[A])
    dotty1.collections.immutable.Iter2.ArrayBuffer[A], [A]()dotty1.collections.immutable.Iter2.ArrayBuffer[A]
typed ident it in method <init>
typed ident it in method <init>
instantiating non-occurring (A?) in Unit
approx A, from below = true, bound = Nothing, inst = Nothing
instantiating (A?) with Nothing
typed ident type Array in val elems
typed ident type AnyRef in val elems
typed ident initElems in val elems
Expansion: x$1 expands to x$1
creating symbol for x$1 in Mode(ImplicitsEnabled)
entered: val x$1 in method elems_$eq and Scopes()
Expansion: x$1 expands to x$1
creating symbol for x$1 in Mode(ImplicitsEnabled)
entered: val x$1 in method len_$eq and Scopes()
using inherited type for iterator; raw: =>
  dotty1.collections.immutable.Iter2.Iterator[
    dotty1$collections$immutable$Iter2$IterableOnce$$A
  ], inst: =>
  dotty1.collections.immutable.Iter2.Iterator[
    dotty1$collections$immutable$Iter2$IterableOnce$$A
  ], inherited: dotty1.collections.immutable.Iter2.Iterator[
  dotty1$collections$immutable$Iter2$ArrayBuffer$$A
]
typed ident type Iterator in method iterator
typed ident type A in method iterator
typed ident elems in method iterator
adapt to subtype Array[AnyRef](ArrayBuffer.this.elems) !<:< ?{ iterator: ? }
typed ident genericWrapArray in method iterator
typed ident wrapRefArray in method iterator
typed ident genericArrayOps in method iterator
typed ident refArrayOps in method iterator
typed ident len in method iterator
instantiating non-occurring (T? >: Object <: AnyRef) in [T0]T0
approx T, from below = true, bound = Object, inst = Object
instantiating (T? >: Object <: AnyRef) with Object
instantiating non-occurring (T? <: AnyRef) in dotty1.collections.immutable.Iter2.Iterator[
  dotty1$collections$immutable$Iter2$ArrayBuffer$$A
]
approx T, from below = true, bound = Nothing, inst = Nothing
instantiating (T? <: AnyRef) with Nothing
using inherited type for buildIterator; raw: =>
  dotty1.collections.immutable.Iter2.Iterator[
    dotty1$collections$immutable$Iter2$IterableOnce$$A
  ], inst: =>
  dotty1.collections.immutable.Iter2.Iterator[
    dotty1$collections$immutable$Iter2$IterableOnce$$A
  ], inherited: dotty1.collections.immutable.Iter2.Iterator[
  dotty1$collections$immutable$Iter2$ArrayBuffer$$A
]
typed ident type Iterator in method buildIterator
typed ident type A in method buildIterator
typed ident type ArrayIterator in method buildIterator
typed ident elems in method buildIterator
typed ident len in method buildIterator
instantiating non-occurring (A?) in [T0]T0
approx A, from below = true, bound = Nothing, inst = Nothing
instantiating (A?) with Nothing
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method fromIterator and Scopes()
Expansion: it: Iterator[B] expands to it: Iterator[B]
creating symbol for it: Iterator[B] in Mode(ImplicitsEnabled)
entered: val it in method fromIterator and Scopes(type B)
typed ident type Iterator in val it
typed ident type B in val it
typed ident type ArrayBuffer in method fromIterator
typed ident type B in method fromIterator
typed ident type ArrayBuffer in method fromIterator
adapt overloaded <overloaded dotty1.collections.immutable.Iter2.ArrayBuffer#<init>> with alternatives [A]
  (initElems: Array[AnyRef], initLen: Int)
    dotty1.collections.immutable.Iter2.ArrayBuffer[A], [A]
  (it: dotty1.collections.immutable.Iter2.ArrayIterator[A])
    dotty1.collections.immutable.Iter2.ArrayBuffer[A], [A]()dotty1.collections.immutable.Iter2.ArrayBuffer[A]
typed ident ArrayIterator in method fromIterator
Expansion: def <init>() expands to def <init>()
creating symbol for def <init>() in Mode(ImplicitsEnabled)
entered: method <init> in module class ArrayIterator$ and Scopes(method companion$class)
ensure first is class  -->
completing module class ArrayIterator$, parents = List(), parentTypes = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object)), parentRefs = List(TypeRef(ThisType(TypeRef(NoPrefix,lang)),Object))
Expansion: def apply[A](elems, len) =
  new
    <derived typetree watching
      case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
         with
      ...[..., ...] {
        A
        val elems
        val len
        import ...._
        private def elem(...) = ...
        private var cur = ...
        def hasNext = ...
        def next = ...
        override def foreach(...): ... = ...
        override def map[...](...): ... = ...
        override def flatMap[...](...): ... = ...
        override def ++[...](...): ... = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >
  [...](..., ...) expands to def apply[A](elems, len) =
  new
    <derived typetree watching
      case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
         with
      ...[..., ...] {
        A
        val elems
        val len
        import ...._
        private def elem(...) = ...
        private var cur = ...
        def hasNext = ...
        def next = ...
        override def foreach(...): ... = ...
        override def map[...](...): ... = ...
        override def flatMap[...](...): ... = ...
        override def ++[...](...): ... = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >
  [...](..., ...)
Expansion: def unapply[A](
  x$1:
    <derived typetree watching
      case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
         with
      ...[..., ...] {
        A
        val elems
        val len
        import ...._
        private def elem(...) = ...
        private var cur = ...
        def hasNext = ...
        def next = ...
        override def foreach(...): ... = ...
        override def map[...](...): ... = ...
        override def flatMap[...](...): ... = ...
        override def ++[...](...): ... = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >[...]
) = x$1 expands to def unapply[A](
  x$1:
    <derived typetree watching
      case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
         with
      ...[..., ...] {
        A
        val elems
        val len
        import ...._
        private def elem(...) = ...
        private var cur = ...
        def hasNext = ...
        def next = ...
        override def foreach(...): ... = ...
        override def map[...](...): ... = ...
        override def flatMap[...](...): ... = ...
        override def ++[...](...): ... = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >[...]
) = x$1
Expansion: private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef] expands to private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]
Expansion: def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =
  it match {
    case it: ArrayIterator[A] =>
      it
    case _ =>
      var elems = new Array[AnyRef](32)
      var len = 0
      def ensureCapacity() = {
        while (len > elems.length) do {
          val newElems = new Array[AnyRef](elems.length * 2)
          Array.copy(elems, 0, newElems, 0, elems.length)
          elems = newElems
        }
      }
      while (it.hasNext) do {
        len += 1
        ensureCapacity()
        elems(len - 1) = widen(it.next)
      }
      ArrayIterator(elems, len)
  } expands to def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =
  it match {
    case it: ArrayIterator[A] =>
      it
    case _ =>
      var elems = new Array[AnyRef](32)
      var len = 0
      def ensureCapacity() = {
        while (len > elems.length) do {
          val newElems = new Array[AnyRef](elems.length * 2)
          Array.copy(elems, 0, newElems, 0, elems.length)
          elems = newElems
        }
      }
      while (it.hasNext) do {
        len += 1
        ensureCapacity()
        elems(len - 1) = widen(it.next)
      }
      ArrayIterator(elems, len)
  }
Expansion: def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {
  var arrayIts = its.map(fromIterator)
  var totalLen = 0
  arrayIts.foreach(_$3 => totalLen += _$3.len)
  val allElems = new Array[AnyRef](totalLen)
  var j = 0
  arrayIts.foreach({
    it => {
      Array.copy(it.elems, 0, allElems, j, it.len)
      j += it.len
    }
  })
  new ArrayIterator(allElems, totalLen)
} expands to def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {
  var arrayIts = its.map(fromIterator)
  var totalLen = 0
  arrayIts.foreach(_$3 => totalLen += _$3.len)
  val allElems = new Array[AnyRef](totalLen)
  var j = 0
  arrayIts.foreach({
    it => {
      Array.copy(it.elems, 0, allElems, j, it.len)
      j += it.len
    }
  })
  new ArrayIterator(allElems, totalLen)
}
creating symbol for def apply[A](elems, len) =
  new
    <derived typetree watching
      case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
         with
      ...[..., ...] {
        A
        val elems
        val len
        import ...._
        private def elem(...) = ...
        private var cur = ...
        def hasNext = ...
        def next = ...
        override def foreach(...): ... = ...
        override def map[...](...): ... = ...
        override def flatMap[...](...): ... = ...
        override def ++[...](...): ... = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >
  [...](..., ...) in Mode(ImplicitsEnabled)
entered: method apply in module class ArrayIterator$ and Scopes(method companion$class, method <init>)
creating symbol for def unapply[A](
  x$1:
    <derived typetree watching
      case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
         with
      ...[..., ...] {
        A
        val elems
        val len
        import ...._
        private def elem(...) = ...
        private var cur = ...
        def hasNext = ...
        def next = ...
        override def foreach(...): ... = ...
        override def map[...](...): ... = ...
        override def flatMap[...](...): ... = ...
        override def ++[...](...): ... = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >[...]
) = x$1 in Mode(ImplicitsEnabled)
entered: method unapply in module class ArrayIterator$ and Scopes(method companion$class, method <init>, method apply)
creating symbol for private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef] in Mode(ImplicitsEnabled)
entered: method widen in module class ArrayIterator$ and Scopes(method companion$class, method <init>, method apply, method unapply)
creating symbol for def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =
  it match {
    case it: ArrayIterator[A] =>
      it
    case _ =>
      var elems = new Array[AnyRef](32)
      var len = 0
      def ensureCapacity() = {
        while (len > elems.length) do {
          val newElems = new Array[AnyRef](elems.length * 2)
          Array.copy(elems, 0, newElems, 0, elems.length)
          elems = newElems
        }
      }
      while (it.hasNext) do {
        len += 1
        ensureCapacity()
        elems(len - 1) = widen(it.next)
      }
      ArrayIterator(elems, len)
  } in Mode(ImplicitsEnabled)
entered: method fromIterator in module class ArrayIterator$ and Scopes(method companion$class, method <init>, method apply, method unapply, method widen)
creating symbol for def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {
  var arrayIts = its.map(fromIterator)
  var totalLen = 0
  arrayIts.foreach(_$3 => totalLen += _$3.len)
  val allElems = new Array[AnyRef](totalLen)
  var j = 0
  arrayIts.foreach({
    it => {
      Array.copy(it.elems, 0, allElems, j, it.len)
      j += it.len
    }
  })
  new ArrayIterator(allElems, totalLen)
} in Mode(ImplicitsEnabled)
entered: method flatten in module class ArrayIterator$ and Scopes(method companion$class, method <init>, method apply, method unapply, method widen, method fromIterator)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method fromIterator and Scopes()
Expansion: it: Iterator[A] expands to it: Iterator[A]
creating symbol for it: Iterator[A] in Mode(ImplicitsEnabled)
entered: val it in method fromIterator and Scopes(type A)
typed ident type Iterator in val it
typed ident type A in val it
typed ident type ArrayIterator in method fromIterator
typed ident type A in method fromIterator
typed ident it in method fromIterator
instantiating non-occurring (A? = B) in [B]
  (it: dotty1.collections.immutable.Iter2.Iterator[B])
    dotty1.collections.immutable.Iter2.ArrayBuffer[B]
approx A, from below = true, bound = B, inst = B
instantiating (A? = B) with B
Expansion: i: Int expands to i: Int
creating symbol for i: Int in Mode(ImplicitsEnabled)
entered: val i in method apply and Scopes()
typed ident type Int in val i
using inherited type for apply; raw: (i: Int)dotty1$collections$immutable$Iter2$Seq$$AA, inst: (i: Int)dotty1$collections$immutable$Iter2$Seq$$AA, inherited: dotty1$collections$immutable$Iter2$ArrayBuffer$$A
typed ident type A in method apply
typed ident elems in method apply
typed ident i in method apply
using inherited type for length; raw: => Int, inst: => Int, inherited: Int
typed ident len in method length
check no double defs class ArrayBuffer
conflict? constructor ArrayBuffer constructor ArrayBuffer
conflict? constructor ArrayBuffer constructor ArrayBuffer
conflict? constructor ArrayBuffer constructor ArrayBuffer
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method map and Scopes()
Expansion: f: (A) => B expands to f: (A) => B
creating symbol for f: (A) => B in Mode(ImplicitsEnabled)
entered: val f in method map and Scopes(type B)
typed ident type A in val f
typed ident type B in val f
typed ident type C in method map
typed ident type B in method map
typed ident c in method map
typed ident c in method map
typed ident f in method map
instantiating non-occurring (B? = B) in [B]
  (f: dotty1$collections$immutable$Iter2$IterableTransforms$$A => B)
    dotty1$collections$immutable$Iter2$IterableTransforms$$C[B]#$apply
approx B, from below = true, bound = B, inst = B
instantiating (B? = B) with B
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method flatMap and Scopes()
Expansion: f: (A) => IterableOnce[B] expands to f: (A) => IterableOnce[B]
creating symbol for f: (A) => IterableOnce[B] in Mode(ImplicitsEnabled)
entered: val f in method flatMap and Scopes(type B)
typed ident type A in val f
typed ident type IterableOnce in val f
typed ident type B in val f
typed ident type C in method flatMap
typed ident type B in method flatMap
typed ident c in method flatMap
typed ident c in method flatMap
Expansion: def $anonfun(_$1: dotty1$collections$immutable$Iter2$IterableTransforms$$A):
  dotty1.collections.immutable.Iter2.IterableOnce[(B? = B)']
 = f(_$1).buildIterator expands to def $anonfun(_$1: dotty1$collections$immutable$Iter2$IterableTransforms$$A):
  dotty1.collections.immutable.Iter2.IterableOnce[(B? = B)']
 = f(_$1).buildIterator
creating symbol for def $anonfun(_$1: dotty1$collections$immutable$Iter2$IterableTransforms$$A):
  dotty1.collections.immutable.Iter2.IterableOnce[(B? = B)']
 = f(_$1).buildIterator in Mode(ImplicitsEnabled)
entered: method $anonfun in method flatMap and Scopes()
Expansion: _$1: dotty1$collections$immutable$Iter2$IterableTransforms$$A expands to _$1: dotty1$collections$immutable$Iter2$IterableTransforms$$A
creating symbol for _$1: dotty1$collections$immutable$Iter2$IterableTransforms$$A in Mode(ImplicitsEnabled)
entered: val _$1 in method $anonfun and Scopes()
typed ident f in method $anonfun
typed ident _$1 in method $anonfun
typed ident $anonfun in method flatMap
instantiating non-occurring (B? = B) in [B]
  (f: dotty1$collections$immutable$Iter2$IterableTransforms$$A =>
    dotty1.collections.immutable.Iter2.IterableOnce[B]
  )dotty1$collections$immutable$Iter2$IterableTransforms$$C[B]#$apply
approx B, from below = true, bound = B, inst = B
instantiating (B? = B) with B
Expansion: B >: A expands to B >: A
creating symbol for B >: A in Mode(ImplicitsEnabled)
entered: type B in method $plus$plus and Scopes()
typed ident type A in type B
Expansion: xs: IterableOnce[B] expands to xs: IterableOnce[B]
creating symbol for xs: IterableOnce[B] in Mode(ImplicitsEnabled)
entered: val xs in method $plus$plus and Scopes(type B)
typed ident type IterableOnce in val xs
typed ident type B in val xs
typed ident type C in method $plus$plus
typed ident type B in method $plus$plus
typed ident c in method $plus$plus
typed ident c in method $plus$plus
typed ident xs in method $plus$plus
instantiating non-occurring (B? = B) in [B >: dotty1$collections$immutable$Iter2$IterableTransforms$$A]
  (xs: dotty1.collections.immutable.Iter2.IterableOnce[B])
    dotty1$collections$immutable$Iter2$IterableTransforms$$C[B]#$apply
approx B, from below = true, bound = B, inst = B
instantiating (B? = B) with B
Expansion: n: Int expands to n: Int
creating symbol for n: Int in Mode(ImplicitsEnabled)
entered: val n in method drop and Scopes()
typed ident type Int in val n
typed ident type C in method drop
typed ident type A in method drop
typed ident c in method drop
typed ident c in method drop
typed ident n in method drop
instantiating non-occurring (B? = dotty1$collections$immutable$Iter2$IterableTransforms$$A) in (n: Int)
  dotty1$collections$immutable$Iter2$IterableTransforms$$C[
    dotty1$collections$immutable$Iter2$IterableTransforms$$A
  ]#$apply
approx B, from below = true, bound = dotty1$collections$immutable$Iter2$IterableTransforms$$A, inst = dotty1$collections$immutable$Iter2$IterableTransforms$$A
instantiating (B? = dotty1$collections$immutable$Iter2$IterableTransforms$$A) with dotty1$collections$immutable$Iter2$IterableTransforms$$A
typed ident type A in method head
typed ident c in method head
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method zip and Scopes()
Expansion: xs: IterableOnce[B] expands to xs: IterableOnce[B]
creating symbol for xs: IterableOnce[B] in Mode(ImplicitsEnabled)
entered: val xs in method zip and Scopes(type B)
typed ident type IterableOnce in val xs
typed ident type B in val xs
typed ident type C in method zip
typed ident type A in method zip
typed ident type B in method zip
typed ident c in method zip
typed ident c in method zip
typed ident xs in method zip
instantiating non-occurring (B? = B) in IterableTransforms.this.c.dotty1$collections$immutable$Iter2$FromIterator$$C[
  (B?
     >: (dotty1$collections$immutable$Iter2$IterableTransforms$$A, (B? = B)) <:
      (
    dotty1$collections$immutable$Iter2$IterableTransforms$$A, B & (B? = B))
  )
]#$apply
approx B, from below = true, bound = B, inst = B
instantiating (B? = B) with B
instantiating non-occurring (B?
   >: (dotty1$collections$immutable$Iter2$IterableTransforms$$A, B') <: (
    dotty1$collections$immutable$Iter2$IterableTransforms$$A
  , B & B')
) in [B]
  (xs: dotty1.collections.immutable.Iter2.IterableOnce[B])
    dotty1$collections$immutable$Iter2$IterableTransforms$$C[(
      dotty1$collections$immutable$Iter2$IterableTransforms$$A
    , B)]#$apply
approx B, from below = true, bound = (dotty1$collections$immutable$Iter2$IterableTransforms$$A, B'), inst = (dotty1$collections$immutable$Iter2$IterableTransforms$$A, B)
instantiating (B?
   >: (dotty1$collections$immutable$Iter2$IterableTransforms$$A, B') <: (
    dotty1$collections$immutable$Iter2$IterableTransforms$$A
  , B & B')
) with (dotty1$collections$immutable$Iter2$IterableTransforms$$A, B)
check no double defs class IterableTransforms
typed ident type A in method IterableTransforms
typed ident type C in method IterableTransforms
typed ident c in method IterableTransforms
typed ident type C in method reverse
typed ident type SA in method reverse
Expansion: val elems = new Array[AnyRef](c.length) expands to val elems = new Array[AnyRef](c.length)
Expansion: var i = elems.length expands to var i = elems.length
Expansion: val it = c.iterator expands to val it = c.iterator
Expansion: val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length)) expands to val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
creating symbol for val elems = new Array[AnyRef](c.length) in Mode(ImplicitsEnabled)
entered: val elems in method reverse and Scopes()
creating symbol for var i = elems.length in Mode(ImplicitsEnabled)
entered: val i in method reverse and Scopes(val elems)
creating symbol for val it = c.iterator in Mode(ImplicitsEnabled)
entered: val it in method reverse and Scopes(val elems, val i)
creating symbol for val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length)) in Mode(ImplicitsEnabled)
entered: val xzz in method reverse and Scopes(val elems, val i, val it)
typed ident type Array in val elems
typed ident type AnyRef in val elems
typed ident c in val elems
typed ident elems in val i
typed ident c in val it
Expansion: <label> def while$(): Unit =
  if (it.hasNext) {
    {
      i -= 1
      elems(i) = it.next.asInstanceOf[AnyRef]
    }
    while$()
  } else () expands to <label> def while$(): Unit =
  if (it.hasNext) {
    {
      i -= 1
      elems(i) = it.next.asInstanceOf[AnyRef]
    }
    while$()
  } else ()
creating symbol for <label> def while$(): Unit =
  if (it.hasNext) {
    {
      i -= 1
      elems(i) = it.next.asInstanceOf[AnyRef]
    }
    while$()
  } else () in Mode(ImplicitsEnabled)
entered: method while$ in method reverse and Scopes()
typed ident it in method while$
typed ident i in method while$
adapt to subtype Int(i) !<:< ?{ -= : ? }
>>>> StoredError: -= is not a member of Int
typed ident i in method while$
adapt overloaded <overloaded Int#-> with alternatives (x: Double)Double, (x: Float)Float, (x: Long)Long, (x: Int)Int, (x: Char)Int, (x: Short)Int, (x: Byte)Int
typed ident elems in method while$
typed ident i in method while$
typed ident type AnyRef in method while$
typed ident it in method while$
typed ident while$ in method while$
typed ident while$ in method reverse
typed ident c in val xzz
typed ident type SA in val xzz
typed ident ArrayIterator in val xzz
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method apply and Scopes()
Expansion: elems expands to elems
Expansion: len expands to len
creating symbol for elems in Mode(ImplicitsEnabled)
entered: val elems in method apply and Scopes(type A)
creating symbol for len in Mode(ImplicitsEnabled)
entered: val len in method apply and Scopes(type A, val elems)
typed ident type A in method apply
typed ident elems in method apply
typed ident len in method apply
typed ident elems in val xzz
typed ident c in val xzz
approx B, from below = true, bound = dotty1$collections$immutable$Iter2$SeqTransforms$$SA, inst = dotty1$collections$immutable$Iter2$SeqTransforms$$SA
instantiating (B? = dotty1$collections$immutable$Iter2$SeqTransforms$$SA) with dotty1$collections$immutable$Iter2$SeqTransforms$$SA
forced instantiation of B = dotty1$collections$immutable$Iter2$SeqTransforms$$SA
typed ident xzz in method reverse
Expansion: p: (SA) => Boolean expands to p: (SA) => Boolean
creating symbol for p: (SA) => Boolean in Mode(ImplicitsEnabled)
entered: val p in method indexWhere and Scopes()
typed ident type SA in val p
typed ident type Boolean in val p
typed ident type Int in method indexWhere
typed ident c in method indexWhere
typed ident p in method indexWhere
check no double defs class SeqTransforms
typed ident type SA in method SeqTransforms
typed ident type C in method SeqTransforms
typed ident c in method SeqTransforms
ensure first is class dotty1.collections.immutable.Iter2.Iterator[
  dotty1$collections$immutable$Iter2$ListIterator$$A
], Product1[
  dotty1.collections.immutable.Iter2.List[
    dotty1$collections$immutable$Iter2$ListIterator$$A
  ]
] --> Object, <notype>
typed ident type List in val current
typed ident type A in val current
typed ident xs in val current
using inherited type for hasNext; raw: => Boolean, inst: => Boolean, inherited: Boolean
typed ident current in method hasNext
using inherited type for next; raw: => dotty1$collections$immutable$Iter2$Iterator$$A, inst: => dotty1$collections$immutable$Iter2$Iterator$$A, inherited: dotty1$collections$immutable$Iter2$ListIterator$$A
Expansion: val res = current.head expands to val res = current.head
creating symbol for val res = current.head in Mode(ImplicitsEnabled)
entered: val res in method next and Scopes()
typed ident current in val res
typed ident current in method next
typed ident current in method next
typed ident res in method next
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method copy and Scopes()
Expansion: xs expands to xs
creating symbol for xs in Mode(ImplicitsEnabled)
entered: val xs in method copy and Scopes(type A)
typed ident type A in method copy
typed ident xs in method copy
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method copy$default$1 and Scopes()
typed ident xs in method copy$default$1
check no double defs class ListIterator
typed ident type ListIterator$ in module ListIterator
typed ident type ListIterator$ in module ListIterator
typed ident ListIterator in module class Iter2$
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method apply and Scopes()
Expansion: xs expands to xs
creating symbol for xs in Mode(ImplicitsEnabled)
entered: val xs in method apply and Scopes(type A)
typed ident type A in method apply
typed ident xs in method apply
check no double defs object ListIterator$
ensure first is class dotty1.collections.immutable.Iter2.Iterator[
  dotty1$collections$immutable$Iter2$ArrayIterator$$A
], Product2[Array[AnyRef], Int] --> Object, <notype>
typed ident ArrayIterator in class ArrayIterator
Expansion: i: Int expands to i: Int
creating symbol for i: Int in Mode(ImplicitsEnabled)
entered: val i in method elem and Scopes()
typed ident type Int in val i
typed ident type A in method elem
typed ident elems in method elem
typed ident i in method elem
Expansion: x$1 expands to x$1
creating symbol for x$1 in Mode(ImplicitsEnabled)
entered: val x$1 in method cur_$eq and Scopes()
using inherited type for hasNext; raw: => Boolean, inst: => Boolean, inherited: Boolean
typed ident cur in method hasNext
adapt overloaded <overloaded Int#<> with alternatives (x: Double)Boolean, (x: Float)Boolean, (x: Long)Boolean, (x: Int)Boolean, (x: Char)Boolean, (x: Short)Boolean, (x: Byte)Boolean
typed ident len in method hasNext
using inherited type for next; raw: => dotty1$collections$immutable$Iter2$Iterator$$A, inst: => dotty1$collections$immutable$Iter2$Iterator$$A, inherited: dotty1$collections$immutable$Iter2$ArrayIterator$$A
Expansion: val res = elem(cur) expands to val res = elem(cur)
creating symbol for val res = elem(cur) in Mode(ImplicitsEnabled)
entered: val res in method next and Scopes()
typed ident elem in val res
typed ident cur in val res
typed ident cur in method next
adapt to subtype Int(ArrayIterator.this.cur) !<:< ?{ += : ? }
>>>> StoredError: += is not a member of Int
typed ident cur in method next
adapt overloaded <overloaded Int#+> with alternatives (x: Double)Double, (x: Float)Float, (x: Long)Long, (x: Int)Int, (x: Char)Int, (x: Short)Int, (x: Byte)Int, (x: String)String
typed ident res in method next
Expansion: f: (A) => Unit expands to f: (A) => Unit
creating symbol for f: (A) => Unit in Mode(ImplicitsEnabled)
entered: val f in method foreach and Scopes()
typed ident type A in val f
typed ident type Unit in val f
typed ident type Unit in method foreach
adapt to subtype Int(0) !<:< ?{ until: ? }
typed ident intWrapper in method foreach
adapt overloaded <overloaded scala.runtime.RichInt#until> with alternatives (end: Int, step: Int)scala.collection.immutable.Range, (end: Int)scala.collection.immutable.Range
typed ident len in method foreach
Expansion: def $anonfun(i: Int): (U?) = f(elem(i)) expands to def $anonfun(i: Int): (U?) = f(elem(i))
creating symbol for def $anonfun(i: Int): (U?) = f(elem(i)) in Mode(ImplicitsEnabled)
entered: method $anonfun in method foreach and Scopes()
Expansion: i: Int expands to i: Int
creating symbol for i: Int in Mode(ImplicitsEnabled)
entered: val i in method $anonfun and Scopes()
typed ident f in method $anonfun
typed ident elem in method $anonfun
typed ident i in method $anonfun
typed ident $anonfun in method foreach
instantiating non-occurring (U? >: Unit) in Unit
approx U, from below = true, bound = Unit, inst = Unit
instantiating (U? >: Unit) with Unit
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method map and Scopes()
Expansion: f: (A) => B expands to f: (A) => B
creating symbol for f: (A) => B in Mode(ImplicitsEnabled)
entered: val f in method map and Scopes(type B)
typed ident type A in val f
typed ident type B in val f
typed ident type ArrayIterator in method map
typed ident type B in method map
Expansion: var mapped = elems expands to var mapped = elems
creating symbol for var mapped = elems in Mode(ImplicitsEnabled)
entered: val mapped in method map and Scopes()
typed ident elems in val mapped
adapt to subtype Int(0) !<:< ?{ until: ? }
typed ident intWrapper in method map
adapt overloaded <overloaded scala.runtime.RichInt#until> with alternatives (end: Int, step: Int)scala.collection.immutable.Range, (end: Int)scala.collection.immutable.Range
typed ident len in method map
Expansion: def $anonfun(i: Int): (U?) = {
  val x = elem(i)
  val y = widen(f(x))
  if (widen(x) ne y) {
    if (mapped eq elems) mapped = new Array[AnyRef](len)
    mapped(i) = y
  }
} expands to def $anonfun(i: Int): (U?) = {
  val x = elem(i)
  val y = widen(f(x))
  if (widen(x) ne y) {
    if (mapped eq elems) mapped = new Array[AnyRef](len)
    mapped(i) = y
  }
}
creating symbol for def $anonfun(i: Int): (U?) = {
  val x = elem(i)
  val y = widen(f(x))
  if (widen(x) ne y) {
    if (mapped eq elems) mapped = new Array[AnyRef](len)
    mapped(i) = y
  }
} in Mode(ImplicitsEnabled)
entered: method $anonfun in method map and Scopes()
Expansion: i: Int expands to i: Int
creating symbol for i: Int in Mode(ImplicitsEnabled)
entered: val i in method $anonfun and Scopes()
Expansion: val x = elem(i) expands to val x = elem(i)
Expansion: val y = widen(f(x)) expands to val y = widen(f(x))
creating symbol for val x = elem(i) in Mode(ImplicitsEnabled)
entered: val x in method $anonfun and Scopes()
creating symbol for val y = widen(f(x)) in Mode(ImplicitsEnabled)
entered: val y in method $anonfun and Scopes(val x)
typed ident elem in val x
typed ident i in val x
typed ident widen in val y
Expansion: x: Any expands to x: Any
creating symbol for x: Any in Mode(ImplicitsEnabled)
entered: val x in method widen and Scopes()
typed ident type Any in val x
typed ident type AnyRef in method widen
typed ident f in val y
typed ident x in val y
typed ident widen in method $anonfun
typed ident x in method $anonfun
typed ident y in method $anonfun
typed ident mapped in method $anonfun
typed ident elems in method $anonfun
typed ident mapped in method $anonfun
typed ident type Array in method $anonfun
typed ident type AnyRef in method $anonfun
typed ident len in method $anonfun
typed ident mapped in method $anonfun
typed ident i in method $anonfun
typed ident y in method $anonfun
typed ident $anonfun in method map
instantiating non-occurring (U? >: Unit) in Unit
approx U, from below = true, bound = Unit, inst = Unit
instantiating (U? >: Unit) with Unit
typed ident mapped in method map
typed ident elems in method map
typed ident type ArrayIterator in method map
typed ident type B in method map
typed ident type ArrayIterator in method map
typed ident mapped in method map
typed ident len in method map
instantiating non-occurring (A? = B) in [B]
  (f: dotty1$collections$immutable$Iter2$ArrayIterator$$A => B)
    dotty1.collections.immutable.Iter2.ArrayIterator[B]
approx A, from below = true, bound = B, inst = B
instantiating (A? = B) with B
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method flatMap and Scopes()
Expansion: f: (A) => IterableOnce[B] expands to f: (A) => IterableOnce[B]
creating symbol for f: (A) => IterableOnce[B] in Mode(ImplicitsEnabled)
entered: val f in method flatMap and Scopes(type B)
typed ident type A in val f
typed ident type IterableOnce in val f
typed ident type B in val f
typed ident type ArrayIterator in method flatMap
typed ident type B in method flatMap
typed ident flatten in method flatMap
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method flatten and Scopes()
Expansion: its: ArrayIterator[Iterator[A]] expands to its: ArrayIterator[Iterator[A]]
creating symbol for its: ArrayIterator[Iterator[A]] in Mode(ImplicitsEnabled)
entered: val its in method flatten and Scopes(type A)
typed ident type ArrayIterator in val its
typed ident type Iterator in val its
typed ident type A in val its
typed ident type ArrayIterator in method flatten
typed ident type A in method flatten
typed ident map in method flatMap
Expansion: def $anonfun(_$2: dotty1$collections$immutable$Iter2$ArrayIterator$$A):
  (B? = dotty1.collections.immutable.Iter2.Iterator[(A? = B)])
 = f(_$2).buildIterator expands to def $anonfun(_$2: dotty1$collections$immutable$Iter2$ArrayIterator$$A):
  (B? = dotty1.collections.immutable.Iter2.Iterator[(A? = B)])
 = f(_$2).buildIterator
creating symbol for def $anonfun(_$2: dotty1$collections$immutable$Iter2$ArrayIterator$$A):
  (B? = dotty1.collections.immutable.Iter2.Iterator[(A? = B)])
 = f(_$2).buildIterator in Mode(ImplicitsEnabled)
entered: method $anonfun in method flatMap and Scopes()
Expansion: _$2: dotty1$collections$immutable$Iter2$ArrayIterator$$A expands to _$2: dotty1$collections$immutable$Iter2$ArrayIterator$$A
creating symbol for _$2: dotty1$collections$immutable$Iter2$ArrayIterator$$A in Mode(ImplicitsEnabled)
entered: val _$2 in method $anonfun and Scopes()
typed ident f in method $anonfun
typed ident _$2 in method $anonfun
typed ident $anonfun in method flatMap
instantiating non-occurring (B? = dotty1.collections.immutable.Iter2.Iterator[(A? = B)]) in dotty1.collections.immutable.Iter2.ArrayIterator[(A? = B)]
approx B, from below = true, bound = dotty1.collections.immutable.Iter2.Iterator[(A? = B)], inst = dotty1.collections.immutable.Iter2.Iterator[(A? = B)]
instantiating (B? = dotty1.collections.immutable.Iter2.Iterator[(A? = B)]) with dotty1.collections.immutable.Iter2.Iterator[(A? = B)]
instantiating non-occurring (A? = B) in [B]
  (f: dotty1$collections$immutable$Iter2$ArrayIterator$$A =>
    dotty1.collections.immutable.Iter2.IterableOnce[B]
  )dotty1.collections.immutable.Iter2.ArrayIterator[B]
approx A, from below = true, bound = B, inst = B
instantiating (A? = B) with B
Expansion: B >: A expands to B >: A
creating symbol for B >: A in Mode(ImplicitsEnabled)
entered: type B in method $plus$plus and Scopes()
typed ident type A in type B
Expansion: that: IterableOnce[B] expands to that: IterableOnce[B]
creating symbol for that: IterableOnce[B] in Mode(ImplicitsEnabled)
entered: val that in method $plus$plus and Scopes(type B)
typed ident type IterableOnce in val that
typed ident type B in val that
typed ident type ArrayIterator in method $plus$plus
typed ident type B in method $plus$plus
Expansion: val thatIterator @ ArrayIterator(elems2, len2) = fromIterator(that.iterator) expands to Thicket {
  private[this] val $1$ =
    fromIterator(that.iterator) @unchecked() match {
      case thatIterator @ ArrayIterator(elems2, len2) =>
        (thatIterator, elems2, len2)
    }
  val thatIterator = $1$._1
  val elems2 = $1$._2
  val len2 = $1$._3
 }
creating symbol for private[this] val $1$ =
  fromIterator(that.iterator) @unchecked() match {
    case thatIterator @ ArrayIterator(elems2, len2) =>
      (thatIterator, elems2, len2)
  } in Mode(ImplicitsEnabled)
entered: val $1$ in method $plus$plus and Scopes()
creating symbol for val thatIterator = $1$._1 in Mode(ImplicitsEnabled)
entered: val thatIterator in method $plus$plus and Scopes(val $1$)
creating symbol for val elems2 = $1$._2 in Mode(ImplicitsEnabled)
entered: val elems2 in method $plus$plus and Scopes(val $1$, val thatIterator)
creating symbol for val len2 = $1$._3 in Mode(ImplicitsEnabled)
entered: val len2 in method $plus$plus and Scopes(val $1$, val thatIterator, val elems2)
typed ident fromIterator in val $1$
typed ident that in val $1$
approx A, from below = true, bound = B, inst = B
instantiating (A? = B) with B
forced instantiation of A = B
typed ident ArrayIterator in val $1$
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method unapply and Scopes()
Expansion: x$1:
  <derived typetree watching
    case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...] with
      ...
    [..., ...] {
      A
      val elems
      val len
      import ...._
      private def elem(...): ... = ...
      private var cur: ... = ...
      def hasNext: ... = ...
      def next: ... = ...
      override def foreach(...): ... = ...
      override def map[...](...): ... = ...
      override def flatMap[...](...): ... = ...
      override def ++[...](...): ... = ...
      def copy[...](..., ...) = ...
      def isDefined = ...
      def _1 = ...
      def _2 = ...
    }
  >[...] expands to x$1:
  <derived typetree watching
    case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...] with
      ...
    [..., ...] {
      A
      val elems
      val len
      import ...._
      private def elem(...): ... = ...
      private var cur: ... = ...
      def hasNext: ... = ...
      def next: ... = ...
      override def foreach(...): ... = ...
      override def map[...](...): ... = ...
      override def flatMap[...](...): ... = ...
      override def ++[...](...): ... = ...
      def copy[...](..., ...) = ...
      def isDefined = ...
      def _1 = ...
      def _2 = ...
    }
  >[...]
creating symbol for x$1:
  <derived typetree watching
    case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...] with
      ...
    [..., ...] {
      A
      val elems
      val len
      import ...._
      private def elem(...): ... = ...
      private var cur: ... = ...
      def hasNext: ... = ...
      def next: ... = ...
      override def foreach(...): ... = ...
      override def map[...](...): ... = ...
      override def flatMap[...](...): ... = ...
      override def ++[...](...): ... = ...
      def copy[...](..., ...) = ...
      def isDefined = ...
      def _1 = ...
      def _2 = ...
    }
  >[...] in Mode(ImplicitsEnabled)
entered: val x$1 in method unapply and Scopes(type A)
typed ident type A in val x$1
typed ident x$1 in method unapply
using inherited type for _1; raw: => scala$Product2$$T1, inst: => scala$Product2$$T1, inherited: Array[AnyRef]
using inherited type for _2; raw: => scala$Product2$$T2, inst: => scala$Product2$$T2, inherited: Int
typed ident elems2 in val $1$
typed ident _ in val $1$
typed bind elems2 @ _ pt = Array[AnyRef] bodytpe = Array[AnyRef]
typed ident len2 in val $1$
typed ident _ in val $1$
typed bind len2 @ _ pt = Int bodytpe = Int
instantiating non-occurring (A? = B) in dotty1.collections.immutable.Iter2.ArrayIterator[B'] @unchecked
approx A, from below = true, bound = B, inst = B
instantiating (A? = B) with B
typed bind thatIterator @ dotty1.collections.immutable.Iter2.ArrayIterator(elems2, len2) pt = dotty1.collections.immutable.Iter2.ArrayIterator[B'] @unchecked bodytpe = dotty1.collections.immutable.Iter2.ArrayIterator[B] @unchecked
typed ident thatIterator in val $1$
typed ident elems2 in val $1$
typed ident len2 in val $1$
interpolate covariant (T1?
   >:
    dotty1.collections.immutable.Iter2.ArrayIterator[B] @unchecked(thatIterator)
) in (
  (T1?
     >:
      dotty1.collections.immutable.Iter2.ArrayIterator[B] @unchecked(
        thatIterator
      )
  )
, (T2? >: Array[AnyRef](elems2)), (T3? >: Int(len2)))
approx T1, from below = true, bound = dotty1.collections.immutable.Iter2.ArrayIterator[B] @unchecked(thatIterator), inst = dotty1.collections.immutable.Iter2.ArrayIterator[B] @unchecked(thatIterator)
instantiating (T1?
   >:
    dotty1.collections.immutable.Iter2.ArrayIterator[B] @unchecked(thatIterator)
) with dotty1.collections.immutable.Iter2.ArrayIterator[B] @unchecked
interpolate covariant (T2? >: Array[AnyRef](elems2)) in (dotty1.collections.immutable.Iter2.ArrayIterator[B] @unchecked',
  (T2? >: Array[AnyRef](elems2))
, (T3? >: Int(len2)))
approx T2, from below = true, bound = Array[AnyRef](elems2), inst = Array[AnyRef](elems2)
instantiating (T2? >: Array[AnyRef](elems2)) with Array[AnyRef]
interpolate covariant (T3? >: Int(len2)) in (dotty1.collections.immutable.Iter2.ArrayIterator[B] @unchecked', Array[AnyRef]'
  ,
(T3? >: Int(len2)))
approx T3, from below = true, bound = Int(len2), inst = Int(len2)
instantiating (T3? >: Int(len2)) with Int
typed ident $1$ in val thatIterator
typed ident $1$ in val elems2
typed ident $1$ in val len2
typed ident len in method $plus$plus
adapt overloaded <overloaded ArrayIterator.this.len.==> with alternatives (x: Double)Boolean, (x: Float)Boolean, (x: Long)Boolean, (x: Int)Boolean, (x: Char)Boolean, (x: Short)Boolean, (x: Byte)Boolean, (x$0: Any)Boolean
typed ident thatIterator in method $plus$plus
typed ident len2 in method $plus$plus
adapt overloaded <overloaded len2.==> with alternatives (x: Double)Boolean, (x: Float)Boolean, (x: Long)Boolean, (x: Int)Boolean, (x: Char)Boolean, (x: Short)Boolean, (x: Byte)Boolean, (x$0: Any)Boolean
typed ident type ArrayIterator in method $plus$plus
typed ident type B in method $plus$plus
Expansion: val resLen = len + len2 expands to val resLen = len + len2
Expansion: val resElems = new Array[AnyRef](resLen) expands to val resElems = new Array[AnyRef](resLen)
creating symbol for val resLen = len + len2 in Mode(ImplicitsEnabled)
entered: val resLen in method $plus$plus and Scopes()
creating symbol for val resElems = new Array[AnyRef](resLen) in Mode(ImplicitsEnabled)
entered: val resElems in method $plus$plus and Scopes(val resLen)
typed ident len in val resLen
adapt overloaded <overloaded ArrayIterator.this.len.+> with alternatives (x: Double)Double, (x: Float)Float, (x: Long)Long, (x: Int)Int, (x: Char)Int, (x: Short)Int, (x: Byte)Int, (x: String)String
typed ident len2 in val resLen
typed ident type Array in val resElems
typed ident type AnyRef in val resElems
typed ident resLen in val resElems
typed ident Array in method $plus$plus
typed ident elems in method $plus$plus
typed ident resElems in method $plus$plus
typed ident len in method $plus$plus
typed ident Array in method $plus$plus
typed ident elems2 in method $plus$plus
typed ident resElems in method $plus$plus
typed ident len in method $plus$plus
typed ident len2 in method $plus$plus
typed ident type ArrayIterator in method $plus$plus
typed ident resElems in method $plus$plus
typed ident resLen in method $plus$plus
instantiating non-occurring (A? = B) in [B >: dotty1$collections$immutable$Iter2$ArrayIterator$$A]
  (that: dotty1.collections.immutable.Iter2.IterableOnce[B])
    dotty1.collections.immutable.Iter2.ArrayIterator[B]
approx A, from below = true, bound = B, inst = B
instantiating (A? = B) with B
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method copy and Scopes()
Expansion: elems expands to elems
Expansion: len expands to len
creating symbol for elems in Mode(ImplicitsEnabled)
entered: val elems in method copy and Scopes(type A)
creating symbol for len in Mode(ImplicitsEnabled)
entered: val len in method copy and Scopes(type A, val elems)
typed ident type A in method copy
typed ident elems in method copy
typed ident len in method copy
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method copy$default$1 and Scopes()
typed ident elems in method copy$default$1
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method copy$default$2 and Scopes()
typed ident len in method copy$default$2
check no double defs class ArrayIterator
typed ident type ArrayIterator$ in module ArrayIterator
typed ident type ArrayIterator$ in module ArrayIterator
ensure first is class  -->
typed ident ArrayIterator in module class Iter2$
typed ident type AnyRef in method widen
typed ident x in method widen
typed ident it in method fromIterator
typed ident type ArrayIterator in method fromIterator
typed ident type A in method fromIterator
typed bind it @ _: dotty1.collections.immutable.Iter2.ArrayIterator[A] pt = dotty1.collections.immutable.Iter2.Iterator[A] bodytpe = dotty1.collections.immutable.Iter2.ArrayIterator[A]
typed ident it in method fromIterator
typed ident _ in method fromIterator
Expansion: var elems = new Array[AnyRef](32) expands to var elems = new Array[AnyRef](32)
Expansion: var len = 0 expands to var len = 0
Expansion: def ensureCapacity() = {
  while (len > elems.length) do {
    val newElems = new Array[AnyRef](elems.length * 2)
    Array.copy(elems, 0, newElems, 0, elems.length)
    elems = newElems
  }
} expands to def ensureCapacity() = {
  while (len > elems.length) do {
    val newElems = new Array[AnyRef](elems.length * 2)
    Array.copy(elems, 0, newElems, 0, elems.length)
    elems = newElems
  }
}
creating symbol for var elems = new Array[AnyRef](32) in Mode(ImplicitsEnabled)
entered: val elems in method fromIterator and Scopes()
creating symbol for var len = 0 in Mode(ImplicitsEnabled)
entered: val len in method fromIterator and Scopes(val elems)
creating symbol for def ensureCapacity() = {
  while (len > elems.length) do {
    val newElems = new Array[AnyRef](elems.length * 2)
    Array.copy(elems, 0, newElems, 0, elems.length)
    elems = newElems
  }
} in Mode(ImplicitsEnabled)
entered: method ensureCapacity in method fromIterator and Scopes(val elems, val len)
typed ident type Array in val elems
typed ident type AnyRef in val elems
Expansion: <label> def while$(): Unit =
  if (len > elems.length) {
    {
      val newElems = new Array[AnyRef](elems.length * 2)
      Array.copy(elems, 0, newElems, 0, elems.length)
      elems = newElems
    }
    while$()
  } else () expands to <label> def while$(): Unit =
  if (len > elems.length) {
    {
      val newElems = new Array[AnyRef](elems.length * 2)
      Array.copy(elems, 0, newElems, 0, elems.length)
      elems = newElems
    }
    while$()
  } else ()
creating symbol for <label> def while$(): Unit =
  if (len > elems.length) {
    {
      val newElems = new Array[AnyRef](elems.length * 2)
      Array.copy(elems, 0, newElems, 0, elems.length)
      elems = newElems
    }
    while$()
  } else () in Mode(ImplicitsEnabled,InferringReturnType)
entered: method while$ in method ensureCapacity and Scopes()
typed ident len in method while$
adapt overloaded <overloaded Int#>> with alternatives (x: Double)Boolean, (x: Float)Boolean, (x: Long)Boolean, (x: Int)Boolean, (x: Char)Boolean, (x: Short)Boolean, (x: Byte)Boolean
typed ident elems in method while$
Expansion: val newElems = new Array[AnyRef](elems.length * 2) expands to val newElems = new Array[AnyRef](elems.length * 2)
creating symbol for val newElems = new Array[AnyRef](elems.length * 2) in Mode(ImplicitsEnabled,InferringReturnType)
entered: val newElems in method while$ and Scopes()
typed ident type Array in val newElems
typed ident type AnyRef in val newElems
typed ident elems in val newElems
adapt overloaded <overloaded Int#*> with alternatives (x: Double)Double, (x: Float)Float, (x: Long)Long, (x: Int)Int, (x: Char)Int, (x: Short)Int, (x: Byte)Int
typed ident Array in method while$
typed ident elems in method while$
typed ident newElems in method while$
typed ident elems in method while$
typed ident elems in method while$
typed ident newElems in method while$
typed ident while$ in method while$
typed ident while$ in method ensureCapacity
Expansion: <label> def while$(): Unit =
  if (it.hasNext) {
    {
      len += 1
      ensureCapacity()
      elems(len - 1) = widen(it.next)
    }
    while$()
  } else () expands to <label> def while$(): Unit =
  if (it.hasNext) {
    {
      len += 1
      ensureCapacity()
      elems(len - 1) = widen(it.next)
    }
    while$()
  } else ()
creating symbol for <label> def while$(): Unit =
  if (it.hasNext) {
    {
      len += 1
      ensureCapacity()
      elems(len - 1) = widen(it.next)
    }
    while$()
  } else () in Mode(ImplicitsEnabled)
entered: method while$ in method fromIterator and Scopes()
typed ident it in method while$
typed ident len in method while$
adapt to subtype Int(len) !<:< ?{ += : ? }
>>>> StoredError: += is not a member of Int
typed ident len in method while$
adapt overloaded <overloaded Int#+> with alternatives (x: Double)Double, (x: Float)Float, (x: Long)Long, (x: Int)Int, (x: Char)Int, (x: Short)Int, (x: Byte)Int, (x: String)String
typed ident ensureCapacity in method while$
typed ident elems in method while$
typed ident len in method while$
adapt overloaded <overloaded Int#-> with alternatives (x: Double)Double, (x: Float)Float, (x: Long)Long, (x: Int)Int, (x: Char)Int, (x: Short)Int, (x: Byte)Int
typed ident widen in method while$
typed ident it in method while$
typed ident while$ in method while$
typed ident while$ in method fromIterator
typed ident ArrayIterator in method fromIterator
typed ident elems in method fromIterator
typed ident len in method fromIterator
instantiating non-occurring (A? = A) in [A]
  (it: dotty1.collections.immutable.Iter2.Iterator[A])
    dotty1.collections.immutable.Iter2.ArrayIterator[A]
approx A, from below = true, bound = A, inst = A
instantiating (A? = A) with A
Expansion: var arrayIts = its.map(fromIterator) expands to var arrayIts = its.map(fromIterator)
Expansion: var totalLen = 0 expands to var totalLen = 0
Expansion: val allElems = new Array[AnyRef](totalLen) expands to val allElems = new Array[AnyRef](totalLen)
Expansion: var j = 0 expands to var j = 0
creating symbol for var arrayIts = its.map(fromIterator) in Mode(ImplicitsEnabled)
entered: val arrayIts in method flatten and Scopes()
creating symbol for var totalLen = 0 in Mode(ImplicitsEnabled)
entered: val totalLen in method flatten and Scopes(val arrayIts)
creating symbol for val allElems = new Array[AnyRef](totalLen) in Mode(ImplicitsEnabled)
entered: val allElems in method flatten and Scopes(val arrayIts, val totalLen)
creating symbol for var j = 0 in Mode(ImplicitsEnabled)
entered: val j in method flatten and Scopes(val arrayIts, val totalLen, val allElems)
typed ident its in val arrayIts
typed ident fromIterator in val arrayIts
Expansion: def $anonfun(it: dotty1.collections.immutable.Iter2.Iterator[A]): (B?) =
  dotty1.collections.immutable.Iter2.ArrayIterator.fromIterator[(A?)](it) expands to def $anonfun(it: dotty1.collections.immutable.Iter2.Iterator[A]): (B?) =
  dotty1.collections.immutable.Iter2.ArrayIterator.fromIterator[(A?)](it)
creating symbol for def $anonfun(it: dotty1.collections.immutable.Iter2.Iterator[A]): (B?) =
  dotty1.collections.immutable.Iter2.ArrayIterator.fromIterator[(A?)](it) in Mode(ImplicitsEnabled,InferringReturnType)
entered: method $anonfun in val arrayIts and Scopes()
Expansion: it: dotty1.collections.immutable.Iter2.Iterator[A] expands to it: dotty1.collections.immutable.Iter2.Iterator[A]
creating symbol for it: dotty1.collections.immutable.Iter2.Iterator[A] in Mode(ImplicitsEnabled,InferringReturnType)
entered: val it in method $anonfun and Scopes()
typed ident it in method $anonfun
instantiating non-occurring (A? = A) in (it: dotty1.collections.immutable.Iter2.Iterator[A])
  (B? >: dotty1.collections.immutable.Iter2.ArrayIterator[(A? = A)])
approx A, from below = true, bound = A, inst = A
instantiating (A? = A) with A
typed ident $anonfun in val arrayIts
approx B, from below = true, bound = dotty1.collections.immutable.Iter2.ArrayIterator[A'], inst = dotty1.collections.immutable.Iter2.ArrayIterator[A]
instantiating (B? >: dotty1.collections.immutable.Iter2.ArrayIterator[A']) with dotty1.collections.immutable.Iter2.ArrayIterator[A]
forced instantiation of B = dotty1.collections.immutable.Iter2.ArrayIterator[A]
typed ident arrayIts in method flatten
Expansion: def $anonfun(_$3: dotty1.collections.immutable.Iter2.ArrayIterator[A]): Unit =
  totalLen += _$3.len expands to def $anonfun(_$3: dotty1.collections.immutable.Iter2.ArrayIterator[A]): Unit =
  totalLen += _$3.len
creating symbol for def $anonfun(_$3: dotty1.collections.immutable.Iter2.ArrayIterator[A]): Unit =
  totalLen += _$3.len in Mode(ImplicitsEnabled)
entered: method $anonfun in method flatten and Scopes()
Expansion: _$3: dotty1.collections.immutable.Iter2.ArrayIterator[A] expands to _$3: dotty1.collections.immutable.Iter2.ArrayIterator[A]
creating symbol for _$3: dotty1.collections.immutable.Iter2.ArrayIterator[A] in Mode(ImplicitsEnabled)
entered: val _$3 in method $anonfun and Scopes()
typed ident totalLen in method $anonfun
adapt to subtype Int(totalLen) !<:< ?{ += : ? }
>>>> StoredError: += is not a member of Int
typed ident totalLen in method $anonfun
adapt overloaded <overloaded Int#+> with alternatives (x: Double)Double, (x: Float)Float, (x: Long)Long, (x: Int)Int, (x: Char)Int, (x: Short)Int, (x: Byte)Int, (x: String)String
typed ident _$3 in method $anonfun
typed ident $anonfun in method flatten
typed ident type Array in val allElems
typed ident type AnyRef in val allElems
typed ident totalLen in val allElems
typed ident arrayIts in method flatten
Expansion: def $anonfun(it: dotty1.collections.immutable.Iter2.ArrayIterator[A]): Unit = {
  Array.copy(it.elems, 0, allElems, j, it.len)
  j += it.len
} expands to def $anonfun(it: dotty1.collections.immutable.Iter2.ArrayIterator[A]): Unit = {
  Array.copy(it.elems, 0, allElems, j, it.len)
  j += it.len
}
creating symbol for def $anonfun(it: dotty1.collections.immutable.Iter2.ArrayIterator[A]): Unit = {
  Array.copy(it.elems, 0, allElems, j, it.len)
  j += it.len
} in Mode(ImplicitsEnabled)
entered: method $anonfun in method flatten and Scopes()
Expansion: it: dotty1.collections.immutable.Iter2.ArrayIterator[A] expands to it: dotty1.collections.immutable.Iter2.ArrayIterator[A]
creating symbol for it: dotty1.collections.immutable.Iter2.ArrayIterator[A] in Mode(ImplicitsEnabled)
entered: val it in method $anonfun and Scopes()
typed ident Array in method $anonfun
typed ident it in method $anonfun
typed ident allElems in method $anonfun
typed ident j in method $anonfun
typed ident it in method $anonfun
typed ident j in method $anonfun
adapt to subtype Int(j) !<:< ?{ += : ? }
>>>> StoredError: += is not a member of Int
typed ident j in method $anonfun
adapt overloaded <overloaded Int#+> with alternatives (x: Double)Double, (x: Float)Float, (x: Long)Long, (x: Int)Int, (x: Char)Int, (x: Short)Int, (x: Byte)Int, (x: String)String
typed ident it in method $anonfun
typed ident $anonfun in method flatten
typed ident type ArrayIterator in method flatten
typed ident allElems in method flatten
typed ident totalLen in method flatten
instantiating non-occurring (A? = A) in [A]
  (its:
    dotty1.collections.immutable.Iter2.ArrayIterator[
      dotty1.collections.immutable.Iter2.Iterator[A]
    ]
  )dotty1.collections.immutable.Iter2.ArrayIterator[A]
approx A, from below = true, bound = A, inst = A
instantiating (A? = A) with A
check no double defs object ArrayIterator$
check no double defs object Iter2$
typed: Iter3.scala
max constraint = Constraint(
 uninstVars = ;
 constrained types =
  [T <: AnyRef](xs: Array[T])scala.collection.mutable.ArrayOps[T]
, [T <: AnyRef](xs: Array[T])scala.collection.mutable.ArrayOps[T], [T0]T0
 bounds =
     T >: Object <: AnyRef
     T <: AnyRef
     T0
 ordering =
)

更改后文本

打开文件

parsed:
package dotty1.collections {
  package immutable {
    import annotation.unchecked.uncheckedVariance
    module object Iter2 extends {
      <trait> trait Iterator[A] extends IterableOnce[A] {
        def hasNext: Boolean
        def next: A
        def iterator = this
        def foreach(f: (A) => Unit): Unit = ???
        def map[B](f: (A) => B): Iterator[B] = ???
        def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
        def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
        def drop(n: Int): Iterator[A] = ???
        def indexWhere(p: (A) => Boolean): Int = {
          var i = 0
          while (hasNext) do {
            if (p(next)) return i
            i += 1
          }
          -1
        }
        def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
      }
      <trait> trait IterableOnce[A] extends {
        def iterator: Iterator[A]
        def buildIterator: Iterator[A] = iterator
      }
      <trait> trait FromIterator[C[X] <: Iterable[X]] extends {
        def fromIterator[B](it: Iterator[B]): C[B]
      }
      <trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[
        Iterable
      ] {}
      <trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {
        def apply(i: Int): AA
        def length: Int
      }
      <trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {
        def isEmpty: Boolean
        def head: A
        def tail: List[A]
        def iterator = new ListIterator[A](this)
        def fromIterator[B](it: Iterator[B]): List[B] =
          it match {
            case ListIterator(xs) =>
              xs
            case _ =>
              if (it.hasNext) Cons(it.next, fromIterator(it)) else
                Nil.asInstanceOf[List[B]]
          }
        def apply(i: Int): A = {
          require(! isEmpty)
          if (i == 0) head else tail.apply(i - 1)
        }
        def length: Int = if (isEmpty) 0 else 1 + tail.length
      }
      case class Cons[A](val x: A, val xs: List[A]) extends List[A] {
        def isEmpty = false
        def head = x
        def tail = xs
      }
      module case object Nil extends List[Nothing] {
        def isEmpty = true
        def head = ???
        def tail = ???
      }
      class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],
        private[this] val initLen: Int
      ) extends Seq[A] with FromIterator[ArrayBuffer] {
        def <init>() = {
          <init>(new Array[AnyRef](16), 0)
          ()
        }
        def <init>(it: ArrayIterator[A]) = {
          <init>(it.elems, it.len)
          ()
        }
        private var elems: Array[AnyRef] = initElems
        private var len = 0
        def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
        override def buildIterator =
          new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
        def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
          new ArrayBuffer(ArrayIterator.fromIterator(it))
        def apply(i: Int) = elems(i).asInstanceOf[A]
        def length = len
      }
      implicit class IterableTransforms[A, C[X] <: Iterable[X]](
        val c: Iterable[A] & FromIterator[C]
      ) extends AnyVal {
        def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
        def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
          c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
        def ++[B >: A](xs: IterableOnce[B]): C[B] =
          c.fromIterator(c.buildIterator ++ xs.buildIterator)
        def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
        def head: A = c.iterator.next
        def zip[B](xs: IterableOnce[B]): C[(A, B)] =
          c.fromIterator(c.iterator.zip(xs.iterator))
      }
      implicit class SeqTransforms[SA, C[X] <: Seq[X]](
        val c: Seq[SA] & FromIterator[C]
      ) extends AnyVal {
        def reverse: C[SA] = {
          val elems = new Array[AnyRef](c.length)
          var i = elems.length
          val it = c.iterator
          while (it.hasNext) do {
            i -= 1
            elems(i) = it.next.asInstanceOf[AnyRef]
          }
          val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
          xzz
        }
        def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
      }
      case class ListIterator[A](val xs: List[A]) extends Iterator[A] {
        private[this] var current: List[A] = xs
        def hasNext = ! current.isEmpty
        def next = {
          val res = current.head
          current = current.tail
          res
        }
      }
      case class ArrayIterator[A](val elems: Array[AnyRef], val len: Int)
         extends
       Iterator[A] {
        import ArrayIterator._
        private def elem(i: Int) = elems(i).asInstanceOf[A]
        private var cur = 0
        def hasNext = cur < len
        def next = {
          val res = elem(cur)
          cur += 1
          res
        }
        override def foreach(f: (A) => Unit): Unit =
          for i <- 0 until len do f(elem(i))
        override def map[B](f: (A) => B): ArrayIterator[B] = {
          var mapped = elems
          for i <- 0 until len do {
            val x = elem(i)
            val y = widen(f(x))
            if (widen(x) ne y) {
              if (mapped eq elems) mapped = new Array[AnyRef](len)
              mapped(i) = y
            }
          }
          if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
            new ArrayIterator(mapped, len)
        }
        override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
          flatten(map(_$2 => f(_$2).buildIterator))
        override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
          val thatIterator @ ArrayIterator(elems2, len2) =
            fromIterator(that.iterator)
          if (len == 0) thatIterator else
            if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
              val resLen = len + len2
              val resElems = new Array[AnyRef](resLen)
              Array.copy(elems, 0, resElems, 0, len)
              Array.copy(elems2, 0, resElems, len, len2)
              new ArrayIterator(resElems, resLen)
            }
        }
      }
      module object ArrayIterator extends {
        private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]
        def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =
          it match {
            case it: ArrayIterator[A] =>
              it
            case _ =>
              var elems = new Array[AnyRef](32)
              var len = 0
              def ensureCapacity() = {
                while (len > elems.length) do {
                  val newElems = new Array[AnyRef](elems.length * 2)
                  Array.copy(elems, 0, newElems, 0, elems.length)
                  elems = newElems
                }
              }
              while (it.hasNext) do {
                len += 1
                ensureCapacity()
                elems(len - 1) = widen(it.next)
              }
              ArrayIterator(elems, len)
          }
        def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {
          var arrayIts = its.map(fromIterator)
          var totalLen = 0
          arrayIts.foreach(_$3 => totalLen += _$3.len)
          val allElems = new Array[AnyRef](totalLen)
          var j = 0
          arrayIts.foreach({
            it => {
              Array.copy(it.elems, 0, allElems, j, it.len)
              j += it.len
            }
          })
          new ArrayIterator(allElems, totalLen)
        }
      }
    }
  }
}
Expansion: module object Iter2 extends {
  <trait> trait Iterator[A] extends IterableOnce[A] {
    def hasNext: Boolean
    def next: A
    def iterator = this
    def foreach(f: (A) => Unit): Unit = ???
    def map[B](f: (A) => B): Iterator[B] = ???
    def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
    def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
    def drop(n: Int): Iterator[A] = ???
    def indexWhere(p: (A) => Boolean): Int = {
      var i = 0
      while (hasNext) do {
        if (p(next)) return i
        i += 1
      }
      -1
    }
    def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
  }
  <trait> trait IterableOnce[A] extends {
    def iterator: Iterator[A]
    def buildIterator: Iterator[A] = iterator
  }
  <trait> trait FromIterator[C[X] <: Iterable[X]] extends {
    def fromIterator[B](it: Iterator[B]): C[B]
  }
  <trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[Iterable
    ]
   {}
  <trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {
    def apply(i: Int): AA
    def length: Int
  }
  <trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {
    def isEmpty: Boolean
    def head: A
    def tail: List[A]
    def iterator = new ListIterator[A](this)
    def fromIterator[B](it: Iterator[B]): List[B] =
      it match {
        case ListIterator(xs) =>
          xs
        case _ =>
          if (it.hasNext) Cons(it.next, fromIterator(it)) else
            Nil.asInstanceOf[List[B]]
      }
    def apply(i: Int): A = {
      require(! isEmpty)
      if (i == 0) head else tail.apply(i - 1)
    }
    def length: Int = if (isEmpty) 0 else 1 + tail.length
  }
  case class Cons[A](val x: A, val xs: List[A]) extends List[A] {
    def isEmpty = false
    def head = x
    def tail = xs
  }
  module case object Nil extends List[Nothing] {
    def isEmpty = true
    def head = ???
    def tail = ???
  }
  class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],
    private[this] val initLen: Int
  ) extends Seq[A] with FromIterator[ArrayBuffer] {
    def <init>() = {
      <init>(new Array[AnyRef](16), 0)
      ()
    }
    def <init>(it: ArrayIterator[A]) = {
      <init>(it.elems, it.len)
      ()
    }
    private var elems: Array[AnyRef] = initElems
    private var len = 0
    def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
    override def buildIterator =
      new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
    def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
      new ArrayBuffer(ArrayIterator.fromIterator(it))
    def apply(i: Int) = elems(i).asInstanceOf[A]
    def length = len
  }
  implicit class IterableTransforms[A, C[X] <: Iterable[X]](
    val c: Iterable[A] & FromIterator[C]
  ) extends AnyVal {
    def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
    def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
      c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
    def ++[B >: A](xs: IterableOnce[B]): C[B] =
      c.fromIterator(c.buildIterator ++ xs.buildIterator)
    def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
    def head: A = c.iterator.next
    def zip[B](xs: IterableOnce[B]): C[(A, B)] =
      c.fromIterator(c.iterator.zip(xs.iterator))
  }
  implicit class SeqTransforms[SA, C[X] <: Seq[X]](
    val c: Seq[SA] & FromIterator[C]
  ) extends AnyVal {
    def reverse: C[SA] = {
      val elems = new Array[AnyRef](c.length)
      var i = elems.length
      val it = c.iterator
      while (it.hasNext) do {
        i -= 1
        elems(i) = it.next.asInstanceOf[AnyRef]
      }
      val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
      xzz
    }
    def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
  }
  case class ListIterator[A](val xs: List[A]) extends Iterator[A] {
    private[this] var current: List[A] = xs
    def hasNext = ! current.isEmpty
    def next = {
      val res = current.head
      current = current.tail
      res
    }
  }
  case class ArrayIterator[A](val elems: Array[AnyRef], val len: Int) extends
    Iterator
  [A] {
    import ArrayIterator._
    private def elem(i: Int) = elems(i).asInstanceOf[A]
    private var cur = 0
    def hasNext = cur < len
    def next = {
      val res = elem(cur)
      cur += 1
      res
    }
    override def foreach(f: (A) => Unit): Unit =
      for i <- 0 until len do f(elem(i))
    override def map[B](f: (A) => B): ArrayIterator[B] = {
      var mapped = elems
      for i <- 0 until len do {
        val x = elem(i)
        val y = widen(f(x))
        if (widen(x) ne y) {
          if (mapped eq elems) mapped = new Array[AnyRef](len)
          mapped(i) = y
        }
      }
      if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
        new ArrayIterator(mapped, len)
    }
    override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
      flatten(map(_$2 => f(_$2).buildIterator))
    override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
      val thatIterator @ ArrayIterator(elems2, len2) =
        fromIterator(that.iterator)
      if (len == 0) thatIterator else
        if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
          val resLen = len + len2
          val resElems = new Array[AnyRef](resLen)
          Array.copy(elems, 0, resElems, 0, len)
          Array.copy(elems2, 0, resElems, len, len2)
          new ArrayIterator(resElems, resLen)
        }
    }
  }
  module object ArrayIterator extends {
    private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]
    def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =
      it match {
        case it: ArrayIterator[A] =>
          it
        case _ =>
          var elems = new Array[AnyRef](32)
          var len = 0
          def ensureCapacity() = {
            while (len > elems.length) do {
              val newElems = new Array[AnyRef](elems.length * 2)
              Array.copy(elems, 0, newElems, 0, elems.length)
              elems = newElems
            }
          }
          while (it.hasNext) do {
            len += 1
            ensureCapacity()
            elems(len - 1) = widen(it.next)
          }
          ArrayIterator(elems, len)
      }
    def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {
      var arrayIts = its.map(fromIterator)
      var totalLen = 0
      arrayIts.foreach(_$3 => totalLen += _$3.len)
      val allElems = new Array[AnyRef](totalLen)
      var j = 0
      arrayIts.foreach({
        it => {
          Array.copy(it.elems, 0, allElems, j, it.len)
          j += it.len
        }
      })
      new ArrayIterator(allElems, totalLen)
    }
  }
} expands to Thicket {
  final lazy module val Iter2: Iter2$ = new Iter2$()
  final module class Iter2$() extends { this: Iter2.type =>
    <trait> trait Iterator[A] extends IterableOnce[A] {
      def hasNext: Boolean
      def next: A
      def iterator = this
      def foreach(f: (A) => Unit): Unit = ???
      def map[B](f: (A) => B): Iterator[B] = ???
      def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
      def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
      def drop(n: Int): Iterator[A] = ???
      def indexWhere(p: (A) => Boolean): Int = {
        var i = 0
        while (hasNext) do {
          if (p(next)) return i
          i += 1
        }
        -1
      }
      def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
    }
    <trait> trait IterableOnce[A] extends {
      def iterator: Iterator[A]
      def buildIterator: Iterator[A] = iterator
    }
    <trait> trait FromIterator[C[X] <: Iterable[X]] extends {
      def fromIterator[B](it: Iterator[B]): C[B]
    }
    <trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[
      Iterable
    ] {}
    <trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {
      def apply(i: Int): AA
      def length: Int
    }
    <trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {
      def isEmpty: Boolean
      def head: A
      def tail: List[A]
      def iterator = new ListIterator[A](this)
      def fromIterator[B](it: Iterator[B]): List[B] =
        it match {
          case ListIterator(xs) =>
            xs
          case _ =>
            if (it.hasNext) Cons(it.next, fromIterator(it)) else
              Nil.asInstanceOf[List[B]]
        }
      def apply(i: Int): A = {
        require(! isEmpty)
        if (i == 0) head else tail.apply(i - 1)
      }
      def length: Int = if (isEmpty) 0 else 1 + tail.length
    }
    case class Cons[A](val x: A, val xs: List[A]) extends List[A] {
      def isEmpty = false
      def head = x
      def tail = xs
    }
    module case object Nil extends List[Nothing] {
      def isEmpty = true
      def head = ???
      def tail = ???
    }
    class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],
      private[this] val initLen: Int
    ) extends Seq[A] with FromIterator[ArrayBuffer] {
      def <init>() = {
        <init>(new Array[AnyRef](16), 0)
        ()
      }
      def <init>(it: ArrayIterator[A]) = {
        <init>(it.elems, it.len)
        ()
      }
      private var elems: Array[AnyRef] = initElems
      private var len = 0
      def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
      override def buildIterator =
        new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
      def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
        new ArrayBuffer(ArrayIterator.fromIterator(it))
      def apply(i: Int) = elems(i).asInstanceOf[A]
      def length = len
    }
    implicit class IterableTransforms[A, C[X] <: Iterable[X]](
      val c: Iterable[A] & FromIterator[C]
    ) extends AnyVal {
      def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
      def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
        c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
      def ++[B >: A](xs: IterableOnce[B]): C[B] =
        c.fromIterator(c.buildIterator ++ xs.buildIterator)
      def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
      def head: A = c.iterator.next
      def zip[B](xs: IterableOnce[B]): C[(A, B)] =
        c.fromIterator(c.iterator.zip(xs.iterator))
    }
    implicit class SeqTransforms[SA, C[X] <: Seq[X]](
      val c: Seq[SA] & FromIterator[C]
    ) extends AnyVal {
      def reverse: C[SA] = {
        val elems = new Array[AnyRef](c.length)
        var i = elems.length
        val it = c.iterator
        while (it.hasNext) do {
          i -= 1
          elems(i) = it.next.asInstanceOf[AnyRef]
        }
        val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
        xzz
      }
      def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
    }
    case class ListIterator[A](val xs: List[A]) extends Iterator[A] {
      private[this] var current: List[A] = xs
      def hasNext = ! current.isEmpty
      def next = {
        val res = current.head
        current = current.tail
        res
      }
    }
    case class ArrayIterator[A](val elems: Array[AnyRef], val len: Int) extends
      Iterator
    [A] {
      import ArrayIterator._
      private def elem(i: Int) = elems(i).asInstanceOf[A]
      private var cur = 0
      def hasNext = cur < len
      def next = {
        val res = elem(cur)
        cur += 1
        res
      }
      override def foreach(f: (A) => Unit): Unit =
        for i <- 0 until len do f(elem(i))
      override def map[B](f: (A) => B): ArrayIterator[B] = {
        var mapped = elems
        for i <- 0 until len do {
          val x = elem(i)
          val y = widen(f(x))
          if (widen(x) ne y) {
            if (mapped eq elems) mapped = new Array[AnyRef](len)
            mapped(i) = y
          }
        }
        if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
          new ArrayIterator(mapped, len)
      }
      override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
        flatten(map(_$2 => f(_$2).buildIterator))
      override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
        val thatIterator @ ArrayIterator(elems2, len2) =
          fromIterator(that.iterator)
        if (len == 0) thatIterator else
          if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
            val resLen = len + len2
            val resElems = new Array[AnyRef](resLen)
            Array.copy(elems, 0, resElems, 0, len)
            Array.copy(elems2, 0, resElems, len, len2)
            new ArrayIterator(resElems, resLen)
          }
      }
    }
    module object ArrayIterator extends {
      private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]
      def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =
        it match {
          case it: ArrayIterator[A] =>
            it
          case _ =>
            var elems = new Array[AnyRef](32)
            var len = 0
            def ensureCapacity() = {
              while (len > elems.length) do {
                val newElems = new Array[AnyRef](elems.length * 2)
                Array.copy(elems, 0, newElems, 0, elems.length)
                elems = newElems
              }
            }
            while (it.hasNext) do {
              len += 1
              ensureCapacity()
              elems(len - 1) = widen(it.next)
            }
            ArrayIterator(elems, len)
        }
      def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {
        var arrayIts = its.map(fromIterator)
        var totalLen = 0
        arrayIts.foreach(_$3 => totalLen += _$3.len)
        val allElems = new Array[AnyRef](totalLen)
        var j = 0
        arrayIts.foreach({
          it => {
            Array.copy(it.elems, 0, allElems, j, it.len)
            j += it.len
          }
        })
        new ArrayIterator(allElems, totalLen)
      }
    }
  }
 }
creating symbol for import annotation.unchecked.uncheckedVariance in Mode(ImplicitsEnabled)
creating symbol for final lazy module val Iter2: Iter2$ = new Iter2$() in Mode(ImplicitsEnabled)
entered: module Iter2 in module class immutable and Scopes(class Iter2$ArrayBuffer, module Iter2$ArrayBuffer, module class Iter2$ArrayBuffer$, class Iter2$ArrayIterator, module Iter2$ArrayIterator, module class Iter2$ArrayIterator$, class Iter2$Cons, module Iter2$Cons, module class Iter2$Cons$, class Iter2$FromIterator, module Iter2$FromIterator, module class Iter2$FromIterator$, class Iter2$Iterable, module Iter2$Iterable, module class Iter2$Iterable$, class Iter2$IterableOnce, module Iter2$IterableOnce, module class Iter2$IterableOnce$, class Iter2$IterableTransforms, module Iter2$IterableTransforms, module class Iter2$IterableTransforms$, class Iter2$Iterator, module Iter2$Iterator, module class Iter2$Iterator$, class Iter2$List, module Iter2$List, module class Iter2$List$, class Iter2$ListIterator, module Iter2$ListIterator, module class Iter2$ListIterator$, class Iter2$Nil, module Iter2$Nil, module class Iter2$Nil$, class Iter2$Seq, module Iter2$Seq, module class Iter2$Seq$, class Iter2$SeqTransforms, module Iter2$SeqTransforms, module class Iter2$SeqTransforms$, class Iter2$View, module Iter2$View, module class Iter2$View$, class Iter2, module Iter2, module class Iter2$)
creating symbol for final module class Iter2$() extends { this: Iter2.type =>
  <trait> trait Iterator[A] extends IterableOnce[A] {
    def hasNext: Boolean
    def next: A
    def iterator = this
    def foreach(f: (A) => Unit): Unit = ???
    def map[B](f: (A) => B): Iterator[B] = ???
    def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
    def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
    def drop(n: Int): Iterator[A] = ???
    def indexWhere(p: (A) => Boolean): Int = {
      var i = 0
      while (hasNext) do {
        if (p(next)) return i
        i += 1
      }
      -1
    }
    def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
  }
  <trait> trait IterableOnce[A] extends {
    def iterator: Iterator[A]
    def buildIterator: Iterator[A] = iterator
  }
  <trait> trait FromIterator[C[X] <: Iterable[X]] extends {
    def fromIterator[B](it: Iterator[B]): C[B]
  }
  <trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[Iterable
    ]
   {}
  <trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {
    def apply(i: Int): AA
    def length: Int
  }
  <trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {
    def isEmpty: Boolean
    def head: A
    def tail: List[A]
    def iterator = new ListIterator[A](this)
    def fromIterator[B](it: Iterator[B]): List[B] =
      it match {
        case ListIterator(xs) =>
          xs
        case _ =>
          if (it.hasNext) Cons(it.next, fromIterator(it)) else
            Nil.asInstanceOf[List[B]]
      }
    def apply(i: Int): A = {
      require(! isEmpty)
      if (i == 0) head else tail.apply(i - 1)
    }
    def length: Int = if (isEmpty) 0 else 1 + tail.length
  }
  case class Cons[A](val x: A, val xs: List[A]) extends List[A] {
    def isEmpty = false
    def head = x
    def tail = xs
  }
  module case object Nil extends List[Nothing] {
    def isEmpty = true
    def head = ???
    def tail = ???
  }
  class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],
    private[this] val initLen: Int
  ) extends Seq[A] with FromIterator[ArrayBuffer] {
    def <init>() = {
      <init>(new Array[AnyRef](16), 0)
      ()
    }
    def <init>(it: ArrayIterator[A]) = {
      <init>(it.elems, it.len)
      ()
    }
    private var elems: Array[AnyRef] = initElems
    private var len = 0
    def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
    override def buildIterator =
      new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
    def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
      new ArrayBuffer(ArrayIterator.fromIterator(it))
    def apply(i: Int) = elems(i).asInstanceOf[A]
    def length = len
  }
  implicit class IterableTransforms[A, C[X] <: Iterable[X]](
    val c: Iterable[A] & FromIterator[C]
  ) extends AnyVal {
    def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
    def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
      c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
    def ++[B >: A](xs: IterableOnce[B]): C[B] =
      c.fromIterator(c.buildIterator ++ xs.buildIterator)
    def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
    def head: A = c.iterator.next
    def zip[B](xs: IterableOnce[B]): C[(A, B)] =
      c.fromIterator(c.iterator.zip(xs.iterator))
  }
  implicit class SeqTransforms[SA, C[X] <: Seq[X]](
    val c: Seq[SA] & FromIterator[C]
  ) extends AnyVal {
    def reverse: C[SA] = {
      val elems = new Array[AnyRef](c.length)
      var i = elems.length
      val it = c.iterator
      while (it.hasNext) do {
        i -= 1
        elems(i) = it.next.asInstanceOf[AnyRef]
      }
      val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
      xzz
    }
    def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
  }
  case class ListIterator[A](val xs: List[A]) extends Iterator[A] {
    private[this] var current: List[A] = xs
    def hasNext = ! current.isEmpty
    def next = {
      val res = current.head
      current = current.tail
      res
    }
  }
  case class ArrayIterator[A](val elems: Array[AnyRef], val len: Int) extends
    Iterator
  [A] {
    import ArrayIterator._
    private def elem(i: Int) = elems(i).asInstanceOf[A]
    private var cur = 0
    def hasNext = cur < len
    def next = {
      val res = elem(cur)
      cur += 1
      res
    }
    override def foreach(f: (A) => Unit): Unit =
      for i <- 0 until len do f(elem(i))
    override def map[B](f: (A) => B): ArrayIterator[B] = {
      var mapped = elems
      for i <- 0 until len do {
        val x = elem(i)
        val y = widen(f(x))
        if (widen(x) ne y) {
          if (mapped eq elems) mapped = new Array[AnyRef](len)
          mapped(i) = y
        }
      }
      if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
        new ArrayIterator(mapped, len)
    }
    override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
      flatten(map(_$2 => f(_$2).buildIterator))
    override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
      val thatIterator @ ArrayIterator(elems2, len2) =
        fromIterator(that.iterator)
      if (len == 0) thatIterator else
        if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
          val resLen = len + len2
          val resElems = new Array[AnyRef](resLen)
          Array.copy(elems, 0, resElems, 0, len)
          Array.copy(elems2, 0, resElems, len, len2)
          new ArrayIterator(resElems, resLen)
        }
    }
  }
  module object ArrayIterator extends {
    private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef]
    def fromIterator[A](it: Iterator[A]): ArrayIterator[A] =
      it match {
        case it: ArrayIterator[A] =>
          it
        case _ =>
          var elems = new Array[AnyRef](32)
          var len = 0
          def ensureCapacity() = {
            while (len > elems.length) do {
              val newElems = new Array[AnyRef](elems.length * 2)
              Array.copy(elems, 0, newElems, 0, elems.length)
              elems = newElems
            }
          }
          while (it.hasNext) do {
            len += 1
            ensureCapacity()
            elems(len - 1) = widen(it.next)
          }
          ArrayIterator(elems, len)
      }
    def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = {
      var arrayIts = its.map(fromIterator)
      var totalLen = 0
      arrayIts.foreach(_$3 => totalLen += _$3.len)
      val allElems = new Array[AnyRef](totalLen)
      var j = 0
      arrayIts.foreach({
        it => {
          Array.copy(it.elems, 0, allElems, j, it.len)
          j += it.len
        }
      })
      new ArrayIterator(allElems, totalLen)
    }
  }
} in Mode(ImplicitsEnabled)
entered: module class Iter2$ in module class immutable and Scopes(class Iter2$ArrayBuffer, module Iter2$ArrayBuffer, module class Iter2$ArrayBuffer$, class Iter2$ArrayIterator, module Iter2$ArrayIterator, module class Iter2$ArrayIterator$, class Iter2$Cons, module Iter2$Cons, module class Iter2$Cons$, class Iter2$FromIterator, module Iter2$FromIterator, module class Iter2$FromIterator$, class Iter2$Iterable, module Iter2$Iterable, module class Iter2$Iterable$, class Iter2$IterableOnce, module Iter2$IterableOnce, module class Iter2$IterableOnce$, class Iter2$IterableTransforms, module Iter2$IterableTransforms, module class Iter2$IterableTransforms$, class Iter2$Iterator, module Iter2$Iterator, module class Iter2$Iterator$, class Iter2$List, module Iter2$List, module class Iter2$List$, class Iter2$ListIterator, module Iter2$ListIterator, module class Iter2$ListIterator$, class Iter2$Nil, module Iter2$Nil, module class Iter2$Nil$, class Iter2$Seq, module Iter2$Seq, module class Iter2$Seq$, class Iter2$SeqTransforms, module Iter2$SeqTransforms, module class Iter2$SeqTransforms$, class Iter2$View, module Iter2$View, module class Iter2$View$, class Iter2, module class Iter2$, module Iter2)
entered: Iter3.scala
typed ident dotty1 in module class <root>
typed ident immutable in module class collections
typed ident annotation in module class immutable
typed ident type Iter2$ in module Iter2
Expansion: def <init>() expands to def <init>()
creating symbol for def <init>() in Mode(ImplicitsEnabled)
entered: method <init> in module class Iter2$ and Scopes()
ensure first is class  -->
completing module class Iter2$, parents = List(), parentTypes = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object)), parentRefs = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object))
Expansion: <trait> trait Iterator[A] extends IterableOnce[A] {
  def hasNext: Boolean
  def next: A
  def iterator = this
  def foreach(f: (A) => Unit): Unit = ???
  def map[B](f: (A) => B): Iterator[B] = ???
  def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
  def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
  def drop(n: Int): Iterator[A] = ???
  def indexWhere(p: (A) => Boolean): Int = {
    var i = 0
    while (hasNext) do {
      if (p(next)) return i
      i += 1
    }
    -1
  }
  def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
} expands to <trait> trait Iterator[A]() extends IterableOnce[A] {
  A
  def hasNext: Boolean
  def next: A
  def iterator = this
  def foreach(f: (A) => Unit): Unit = ???
  def map[B](f: (A) => B): Iterator[B] = ???
  def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
  def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
  def drop(n: Int): Iterator[A] = ???
  def indexWhere(p: (A) => Boolean): Int = {
    var i = 0
    while (hasNext) do {
      if (p(next)) return i
      i += 1
    }
    -1
  }
  def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
}
Expansion: <trait> trait IterableOnce[A] extends {
  def iterator: Iterator[A]
  def buildIterator: Iterator[A] = iterator
} expands to <trait> trait IterableOnce[A]() extends {
  A
  def iterator: Iterator[A]
  def buildIterator: Iterator[A] = iterator
}
Expansion: <trait> trait FromIterator[C[X] <: Iterable[X]] extends {
  def fromIterator[B](it: Iterator[B]): C[B]
} expands to <trait> trait FromIterator[C[X] <: Iterable[X]]() extends {
  C[X]
  def fromIterator[B](it: Iterator[B]): C[B]
}
Expansion: <trait> trait Iterable[IA] extends IterableOnce[IA] with FromIterator[Iterable]
  {
} expands to <trait> trait Iterable[IA]() extends IterableOnce[IA] with FromIterator[Iterable
  ]
 {
  IA
}
Expansion: <trait> trait Seq[AA] extends Iterable[AA] with FromIterator[Seq] {
  def apply(i: Int): AA
  def length: Int
} expands to <trait> trait Seq[AA]() extends Iterable[AA] with FromIterator[Seq] {
  AA
  def apply(i: Int): AA
  def length: Int
}
Expansion: <trait> sealed trait List[A] extends Seq[A] with FromIterator[List] {
  def isEmpty: Boolean
  def head: A
  def tail: List[A]
  def iterator = new ListIterator[A](this)
  def fromIterator[B](it: Iterator[B]): List[B] =
    it match {
      case ListIterator(xs) =>
        xs
      case _ =>
        if (it.hasNext) Cons(it.next, fromIterator(it)) else
          Nil.asInstanceOf[List[B]]
    }
  def apply(i: Int): A = {
    require(! isEmpty)
    if (i == 0) head else tail.apply(i - 1)
  }
  def length: Int = if (isEmpty) 0 else 1 + tail.length
} expands to <trait> sealed trait List[A]() extends Seq[A] with FromIterator[List] {
  A
  def isEmpty: Boolean
  def head: A
  def tail: List[A]
  def iterator = new ListIterator[A](this)
  def fromIterator[B](it: Iterator[B]): List[B] =
    it match {
      case ListIterator(xs) =>
        xs
      case _ =>
        if (it.hasNext) Cons(it.next, fromIterator(it)) else
          Nil.asInstanceOf[List[B]]
    }
  def apply(i: Int): A = {
    require(! isEmpty)
    if (i == 0) head else tail.apply(i - 1)
  }
  def length: Int = if (isEmpty) 0 else 1 + tail.length
}
Expansion: case class Cons[A](val x: A, val xs: List[A]) extends List[A] {
  def isEmpty = false
  def head = x
  def tail = xs
} expands to Thicket {
  case class Cons[A](x: A, xs: List[A]) extends List[A] with Product2[A, List[A]
    ]
   {
    A
    val x
    val xs
    def isEmpty = false
    def head = x
    def tail = xs
    def copy[A](x = x @scala.annotation.unchecked.uncheckedVariance(),
      xs = xs @scala.annotation.unchecked.uncheckedVariance()
    ) =
      new
        <derived typetree watching
          case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[...,
            ...
          ] {
            A
            val x
            val xs
            def isEmpty = ...
            def head = ...
            def tail = ...
            def copy[...](..., ...) = ...
            def isDefined = ...
            def _1 = ...
            def _2 = ...
          }
        >
      [...](..., ...)
    ...
    ...
    ...
  }
  final lazy module val Cons: ... = ...
  final module class Cons$() extends ... { this: ... =>
    ...
    ...
  }
 }
Expansion: module case object Nil extends List[Nothing] {
  def isEmpty = true
  def head = ???
  def tail = ???
} expands to Thicket {
  final lazy module case val Nil: Nil$ = new Nil$()
  final module class Nil$() extends List[Nothing] { this: Nil.type =>
    def isEmpty = true
    def head = ???
    def tail = ???
  }
 }
Expansion: class ArrayBuffer[A] private(private[this] val initElems: Array[AnyRef],
  private[this] val initLen: Int
) extends Seq[A] with FromIterator[ArrayBuffer] {
  def <init>() = {
    <init>(new Array[AnyRef](16), 0)
    ()
  }
  def <init>(it: ArrayIterator[A]) = {
    <init>(it.elems, it.len)
    ()
  }
  private var elems: Array[AnyRef] = initElems
  private var len = 0
  def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
  override def buildIterator =
    new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
  def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
    new ArrayBuffer(ArrayIterator.fromIterator(it))
  def apply(i: Int) = elems(i).asInstanceOf[A]
  def length = len
} expands to class ArrayBuffer[A] private(initElems: Array[AnyRef], initLen: Int) extends Seq
  [
A] with FromIterator[ArrayBuffer] {
  A
  private[this] val initElems
  private[this] val initLen
  def <init>[A]() = {
    <init>(new Array[AnyRef](16), 0)
    ()
  }
  def <init>[A](it: ArrayIterator[A]) = {
    <init>(it.elems, it.len)
    ()
  }
  private var elems: Array[AnyRef] = initElems
  private var len = 0
  def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
  override def buildIterator =
    new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
  def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
    new ArrayBuffer(ArrayIterator.fromIterator(it))
  def apply(i: Int) = elems(i).asInstanceOf[A]
  def length = len
}
Expansion: implicit class IterableTransforms[A, C[X] <: Iterable[X]](
  val c: Iterable[A] & FromIterator[C]
) extends AnyVal {
  def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
  def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
    c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
  def ++[B >: A](xs: IterableOnce[B]): C[B] =
    c.fromIterator(c.buildIterator ++ xs.buildIterator)
  def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
  def head: A = c.iterator.next
  def zip[B](xs: IterableOnce[B]): C[(A, B)] =
    c.fromIterator(c.iterator.zip(xs.iterator))
} expands to Thicket {
  implicit class IterableTransforms[A, C[X] <: Iterable[X]](
    c: Iterable[A] & FromIterator[C]
  ) extends AnyVal {
    A
    C[X]
    val c
    def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
    def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
      c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
    def ++[B >: A](xs: IterableOnce[B]): C[B] =
      c.fromIterator(c.buildIterator ++ xs.buildIterator)
    def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
    def head: A = c.iterator.next
    def zip[B](xs: IterableOnce[B]): C[(A, B)] =
      c.fromIterator(c.iterator.zip(xs.iterator))
  }
  implicit def IterableTransforms[A, C[X] <: Iterable[X]](
    c: Iterable[A] & FromIterator[C]
  ):
    <derived typetree watching
      implicit class IterableTransforms[A..., C[...]...](c: ...) extends AnyVal
        {

A
  val x
  val xs
  def isEmpty = false
  def head = x
  def tail = xs
  def copy[A](x = x @scala.annotation.unchecked.uncheckedVariance(),
    xs = xs @scala.annotation.unchecked.uncheckedVariance()
  ) =
    new
      <derived typetree watching
        case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[...,
          ...
        ] {
          A
          val x
          val xs
          def isEmpty = ...
          def head = ...
          def tail = ...
          def copy[...](..., ...) = ...
          def isDefined = ...
          def _1 = ...
          def _2 = ...
        }
      >
    [...](..., ...)
  def isDefined = ...
  def _1 = ...
  def _2 = ...
} in Mode(ImplicitsEnabled)
Expansion: A expands to Thicket {
  dotty1$collections$immutable$Iter2$Cons$$A
  private[this] type A = dotty1$collections$immutable$Iter2$Cons$$A
 }
Expansion: val x expands to val x
Expansion: val xs expands to val xs
creating symbol for dotty1$collections$immutable$Iter2$Cons$$A in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$Cons$$A in class Cons and Scopes()
creating symbol for private[this] type A = dotty1$collections$immutable$Iter2$Cons$$A in Mode(ImplicitsEnabled)
entered: type A in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A)
creating symbol for val x in Mode(ImplicitsEnabled)
entered: val x in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A)
creating symbol for val xs in Mode(ImplicitsEnabled)
entered: val xs in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A, val x)
entered: class Cons in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List)
creating symbol for final lazy module val Cons: Cons$ = new Cons$() in Mode(ImplicitsEnabled)
entered: module Cons in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons)
creating symbol for final module class Cons$() extends AnyRef { this: Cons.type =>
  def apply[A](x, xs) =
    new
      <derived typetree watching
        case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[...,
          ...
        ] {
          A
          val x
          val xs
          def isEmpty = ...
          def head = ...
          def tail = ...
          def copy[...](..., ...) = ...
          def isDefined = ...
          def _1 = ...
          def _2 = ...
        }
      >
    [...](..., ...)
  def unapply[...](...) = ...
} in Mode(ImplicitsEnabled)
entered: module class Cons$ in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons)
creating symbol for final lazy module case val Nil: Nil$ = new Nil$() in Mode(ImplicitsEnabled)
entered: module Nil in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$)
creating symbol for final module class Nil$() extends List[Nothing] { this: Nil.type =>
  def isEmpty = true
  def head = ???
  def tail = ???
} in Mode(ImplicitsEnabled)
entered: module class Nil$ in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil)
creating symbol for class ArrayBuffer[A] private(initElems: Array[AnyRef], initLen: Int) extends Seq
  [
A] with FromIterator[ArrayBuffer] {
  A
  private[this] val initElems
  private[this] val initLen
  def <init>[A]() = {
    <init>(new Array[AnyRef](16), 0)
    ()
  }
  def <init>[A](it: ArrayIterator[A]) = {
    <init>(it.elems, it.len)
    ()
  }
  private var elems: Array[AnyRef] = initElems
  private var len = 0
  def iterator = elems.iterator.take(len).asInstanceOf[Iterator[A]]
  override def buildIterator =
    new ArrayIterator(elems, len).asInstanceOf[Iterator[A]]
  def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] =
    new ArrayBuffer(ArrayIterator.fromIterator(it))
  def apply(i: Int) = elems(i).asInstanceOf[A]
  def length = len
} in Mode(ImplicitsEnabled)
Expansion: A expands to Thicket {
  dotty1$collections$immutable$Iter2$ArrayBuffer$$A
  private[this] type A = dotty1$collections$immutable$Iter2$ArrayBuffer$$A
 }
Expansion: private[this] val initElems expands to private[this] val initElems
Expansion: private[this] val initLen expands to private[this] val initLen
creating symbol for dotty1$collections$immutable$Iter2$ArrayBuffer$$A in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$ArrayBuffer$$A in class ArrayBuffer and Scopes()
creating symbol for private[this] type A = dotty1$collections$immutable$Iter2$ArrayBuffer$$A in Mode(ImplicitsEnabled)
entered: type A in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A)
creating symbol for private[this] val initElems in Mode(ImplicitsEnabled)
entered: val initElems in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A)
creating symbol for private[this] val initLen in Mode(ImplicitsEnabled)
entered: val initLen in class ArrayBuffer and Scopes(type dotty1$collections$immutable$Iter2$ArrayBuffer$$A, type A, val initElems)
entered: class ArrayBuffer in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$)
creating symbol for implicit class IterableTransforms[A, C[X] <: Iterable[X]](
  c: Iterable[A] & FromIterator[C]
) extends AnyVal {
  A
  C[X]
  val c
  def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
  def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
    c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
  def ++[B >: A](xs: IterableOnce[B]): C[B] =
    c.fromIterator(c.buildIterator ++ xs.buildIterator)
  def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
  def head: A = c.iterator.next
  def zip[B](xs: IterableOnce[B]): C[(A, B)] =
    c.fromIterator(c.iterator.zip(xs.iterator))
} in Mode(ImplicitsEnabled)
Expansion: A expands to Thicket {
  dotty1$collections$immutable$Iter2$IterableTransforms$$A
  private[this] type A =
    dotty1$collections$immutable$Iter2$IterableTransforms$$A
 }
Expansion: C[X] expands to Thicket {
  dotty1$collections$immutable$Iter2$IterableTransforms$$C[X]
  private[this] type C =
    dotty1$collections$immutable$Iter2$IterableTransforms$$C
 }
Expansion: val c expands to val c
creating symbol for dotty1$collections$immutable$Iter2$IterableTransforms$$A in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$IterableTransforms$$A in class IterableTransforms and Scopes()
creating symbol for private[this] type A = dotty1$collections$immutable$Iter2$IterableTransforms$$A in Mode(ImplicitsEnabled)
entered: type A in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A)
creating symbol for dotty1$collections$immutable$Iter2$IterableTransforms$$C[X] in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$IterableTransforms$$C in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A)
creating symbol for private[this] type C = dotty1$collections$immutable$Iter2$IterableTransforms$$C in Mode(ImplicitsEnabled)
entered: type C in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C)
creating symbol for val c in Mode(ImplicitsEnabled)
entered: val c in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C)
entered: class IterableTransforms in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer)
creating symbol for implicit def IterableTransforms[A, C[X] <: Iterable[X]](
  c: Iterable[A] & FromIterator[C]
):
  <derived typetree watching
    implicit class IterableTransforms[A..., C[...]...](c: ...) extends AnyVal {
      A
      C[...]
      val c
      def map[...](...): ... = ...
      def flatMap[...](...): ... = ...
      def ++[...](...): ... = ...
      def drop(...): ... = ...
      def head: ... = ...
      def zip[...](...): ... = ...
    }
  >[..., ...]
 = ...(...) in Mode(ImplicitsEnabled)
entered: method IterableTransforms in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms)
creating symbol for implicit class SeqTransforms[SA, C[X] <: Seq[X]](c: Seq[SA] & FromIterator[C])
   extends
 AnyVal {
  SA
  C[X]
  val c
  def reverse: C[SA] = {
    val elems = new Array[AnyRef](c.length)
    var i = elems.length
    val it = c.iterator
    while (it.hasNext) do {
      i -= 1
      elems(i) = it.next.asInstanceOf[AnyRef]
    }
    val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
    xzz
  }
  def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
} in Mode(ImplicitsEnabled)
Expansion: SA expands to Thicket {
  dotty1$collections$immutable$Iter2$SeqTransforms$$SA
  private[this] type SA = dotty1$collections$immutable$Iter2$SeqTransforms$$SA
 }
Expansion: C[X] expands to Thicket {
  dotty1$collections$immutable$Iter2$SeqTransforms$$C[X]
  private[this] type C = dotty1$collections$immutable$Iter2$SeqTransforms$$C
 }
Expansion: val c expands to val c
creating symbol for dotty1$collections$immutable$Iter2$SeqTransforms$$SA in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$SeqTransforms$$SA in class SeqTransforms and Scopes()
creating symbol for private[this] type SA = dotty1$collections$immutable$Iter2$SeqTransforms$$SA in Mode(ImplicitsEnabled)
entered: type SA in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA)
creating symbol for dotty1$collections$immutable$Iter2$SeqTransforms$$C[X] in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$SeqTransforms$$C in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA, type SA)
creating symbol for private[this] type C = dotty1$collections$immutable$Iter2$SeqTransforms$$C in Mode(ImplicitsEnabled)
entered: type C in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA, type SA, type dotty1$collections$immutable$Iter2$SeqTransforms$$C)
creating symbol for val c in Mode(ImplicitsEnabled)
entered: val c in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA, type SA, type dotty1$collections$immutable$Iter2$SeqTransforms$$C, type C)
entered: class SeqTransforms in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms)
creating symbol for implicit def SeqTransforms[SA, C[X] <: Seq[X]](c: Seq[SA] & FromIterator[C]):
  <derived typetree watching
    implicit class SeqTransforms[SA..., C[...]...](c: ...) extends AnyVal {
      SA
      C[...]
      val c
      def reverse: ... = ...
      def indexWhere(...): ... = ...
    }
  >[..., ...]
 = ...(...) in Mode(ImplicitsEnabled)
entered: method SeqTransforms in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms)
creating symbol for case class ListIterator[A](xs: List[A]) extends Iterator[A] with Product1[
  List[A]
] {
  A
  val xs
  private[this] var current: List[A] = xs
  def hasNext = ! current.isEmpty
  def next = {
    val res = current.head
    current = current.tail
    res
  }
  def copy[A](xs = xs @scala.annotation.unchecked.uncheckedVariance()) =
    new
      <derived typetree watching
        case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
          A
          val xs
          private[this] var current: ... = ...
          def hasNext = ...
          def next = ...
          def copy[...](...) = ...
          def isDefined = ...
          def _1 = ...
        }
      >
    [...](...)
  def isDefined = ...
  def _1 = ...
} in Mode(ImplicitsEnabled)
Expansion: A expands to Thicket {
  dotty1$collections$immutable$Iter2$ListIterator$$A
  private[this] type A = dotty1$collections$immutable$Iter2$ListIterator$$A
 }
Expansion: val xs expands to val xs
creating symbol for dotty1$collections$immutable$Iter2$ListIterator$$A in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$ListIterator$$A in class ListIterator and Scopes()
creating symbol for private[this] type A = dotty1$collections$immutable$Iter2$ListIterator$$A in Mode(ImplicitsEnabled)
entered: type A in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A)
creating symbol for val xs in Mode(ImplicitsEnabled)
entered: val xs in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A)
entered: class ListIterator in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms, method SeqTransforms)
creating symbol for final lazy module val ListIterator: ListIterator$ = new ListIterator$() in Mode(ImplicitsEnabled)
entered: module ListIterator in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms, method SeqTransforms, class ListIterator)
creating symbol for final module class ListIterator$() extends AnyRef { this: ListIterator.type =>
  def apply[A](xs) =
    new
      <derived typetree watching
        case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
          A
          val xs
          private[this] var current: ... = ...
          def hasNext = ...
          def next = ...
          def copy[...](...) = ...
          def isDefined = ...
          def _1 = ...
        }
      >
    [...](...)
  def unapply[...](...) = ...
} in Mode(ImplicitsEnabled)
entered: module class ListIterator$ in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms, method SeqTransforms, class ListIterator, module ListIterator)
creating symbol for case class ArrayIterator[A](elems: Array[AnyRef], len: Int) extends Iterator[A]
   with
Product2[Array[AnyRef], Int] {
  A
  val elems
  val len
  import ArrayIterator._
  private def elem(i: Int) = elems(i).asInstanceOf[A]
  private var cur = 0
  def hasNext = cur < len
  def next = {
    val res = elem(cur)
    cur += 1
    res
  }
  override def foreach(f: (A) => Unit): Unit =
    for i <- 0 until len do f(elem(i))
  override def map[B](f: (A) => B): ArrayIterator[B] = {
    var mapped = elems
    for i <- 0 until len do {
      val x = elem(i)
      val y = widen(f(x))
      if (widen(x) ne y) {
        if (mapped eq elems) mapped = new Array[AnyRef](len)
        mapped(i) = y
      }
    }
    if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] else
      new ArrayIterator(mapped, len)
  }
  override def flatMap[B](f: (A) => IterableOnce[B]): ArrayIterator[B] =
    flatten(map(_$2 => f(_$2).buildIterator))
  override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = {
    val thatIterator @ ArrayIterator(elems2, len2) = fromIterator(that.iterator)
    if (len == 0) thatIterator else
      if (len2 == 0) this.asInstanceOf[ArrayIterator[B]] else {
        val resLen = len + len2
        val resElems = new Array[AnyRef](resLen)
        Array.copy(elems, 0, resElems, 0, len)
        Array.copy(elems2, 0, resElems, len, len2)
        new ArrayIterator(resElems, resLen)
      }
  }
  def copy[A](elems = elems @scala.annotation.unchecked.uncheckedVariance(),
    len = len @scala.annotation.unchecked.uncheckedVariance()
  ) =
    new
      <derived typetree watching
        case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
           with
        ...[..., ...] {
          A
          val elems
          val len
          import ...._
          private def elem(...) = ...
          private var cur = ...
          def hasNext = ...
          def next = ...
          override def foreach(...): ... = ...
          override def map[...](...): ... = ...
          override def flatMap[...](...): ... = ...
          override def ++[...](...): ... = ...
          def copy[...](..., ...) = ...
          def isDefined = ...
          def _1 = ...
          def _2 = ...
        }
      >
    [...](..., ...)
  def isDefined = ...
  def _1 = ...
  def _2 = ...
} in Mode(ImplicitsEnabled)
Expansion: A expands to Thicket {
  dotty1$collections$immutable$Iter2$ArrayIterator$$A
  private[this] type A = dotty1$collections$immutable$Iter2$ArrayIterator$$A
 }
Expansion: val elems expands to val elems
Expansion: val len expands to val len
creating symbol for dotty1$collections$immutable$Iter2$ArrayIterator$$A in Mode(ImplicitsEnabled)
entered: type dotty1$collections$immutable$Iter2$ArrayIterator$$A in class ArrayIterator and Scopes()
creating symbol for private[this] type A = dotty1$collections$immutable$Iter2$ArrayIterator$$A in Mode(ImplicitsEnabled)
entered: type A in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A)
creating symbol for val elems in Mode(ImplicitsEnabled)
entered: val elems in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A)
creating symbol for val len in Mode(ImplicitsEnabled)
entered: val len in class ArrayIterator and Scopes(type dotty1$collections$immutable$Iter2$ArrayIterator$$A, type A, val elems)
entered: class ArrayIterator in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms, method SeqTransforms, class ListIterator, module ListIterator, module class ListIterator$)
creating symbol for final lazy module val ArrayIterator: ArrayIterator$ = new ArrayIterator$() in Mode(ImplicitsEnabled)
entered: module ArrayIterator in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms, method SeqTransforms, class ListIterator, module ListIterator, module class ListIterator$, class ArrayIterator)
creating symbol for final module class ArrayIterator$() extends { this: ArrayIterator.type =>
  def apply[A](elems, len) =
    new
      <derived typetree watching
        case class ArrayIterator[A...](elems: ..., len: ...) extends ...[...]
           with
        ...[..., ...] {
          A
          val elems
          val len
          import ...._
          private def elem(...) = ...
          private var cur = ...
          def hasNext = ...
          def next = ...
          override def foreach(...): ... = ...
          override def map[...](...): ... = ...
          override def flatMap[...](...): ... = ...
          override def ++[...](...): ... = ...
          def copy[...](..., ...) = ...
          def isDefined = ...
          def _1 = ...
          def _2 = ...
        }
      >
    [...](..., ...)
  def unapply[...](...) = ...
  private def widen(...): ... = ...
  def fromIterator[...](...): ... = ...
  def flatten[...](...): ... = ...
} in Mode(ImplicitsEnabled)
entered: module class ArrayIterator$ in module class Iter2$ and Scopes(method <init>, class Iterator, class IterableOnce, class FromIterator, class Iterable, class Seq, class List, class Cons, module Cons, module class Cons$, module Nil, module class Nil$, class ArrayBuffer, class IterableTransforms, method IterableTransforms, class SeqTransforms, method SeqTransforms, class ListIterator, module ListIterator, module class ListIterator$, class ArrayIterator, module ArrayIterator)
typed ident type Iter2$ in module Iter2
ensure first is class  -->
typed ident Iter2 in module class immutable
Expansion: def <init>[A]() expands to def <init>[A]()
creating symbol for def <init>[A]() in Mode(ImplicitsEnabled)
entered: method <init> in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
typed ident type IterableOnce in method <init>
Expansion: def <init>[A]() expands to def <init>[A]()
creating symbol for def <init>[A]() in Mode(ImplicitsEnabled)
entered: method <init> in class IterableOnce and Scopes(type dotty1$collections$immutable$Iter2$IterableOnce$$A, type A)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
ensure first is class  -->
completing class IterableOnce, parents = List(), parentTypes = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object)), parentRefs = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object))
Expansion: def iterator: Iterator[A] expands to def iterator: Iterator[A]
Expansion: def buildIterator: Iterator[A] = iterator expands to def buildIterator: Iterator[A] = iterator
creating symbol for def iterator: Iterator[A] in Mode(ImplicitsEnabled)
entered: method iterator in class IterableOnce and Scopes(type dotty1$collections$immutable$Iter2$IterableOnce$$A, type A, method <init>)
creating symbol for def buildIterator: Iterator[A] = iterator in Mode(ImplicitsEnabled)
entered: method buildIterator in class IterableOnce and Scopes(type dotty1$collections$immutable$Iter2$IterableOnce$$A, type A, method <init>, method iterator)
typed ident type A in method <init>
typed ident type dotty1$collections$immutable$Iter2$Iterator$$A in type A
ensure first is class dotty1.collections.immutable.Iter2.IterableOnce[
  dotty1$collections$immutable$Iter2$Iterator$$A
] --> Object
completing class Iterator, parents = List(AppliedTypeTree(Ident(IterableOnce),List(Ident(A)))), parentTypes = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),IterableOnce), dotty1$collections$immutable$Iter2$IterableOnce$$A, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Iterator)),dotty1$collections$immutable$Iter2$Iterator$$A)) | 9760950)), parentRefs = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),IterableOnce))
Expansion: def hasNext: Boolean expands to def hasNext: Boolean
Expansion: def next: A expands to def next: A
Expansion: def iterator = this expands to def iterator = this
Expansion: def foreach(f: (A) => Unit): Unit = ??? expands to def foreach(f: (A) => Unit): Unit = ???
Expansion: def map[B](f: (A) => B): Iterator[B] = ??? expands to def map[B](f: (A) => B): Iterator[B] = ???
Expansion: def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ??? expands to def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ???
Expansion: def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ??? expands to def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ???
Expansion: def drop(n: Int): Iterator[A] = ??? expands to def drop(n: Int): Iterator[A] = ???
Expansion: def indexWhere(p: (A) => Boolean): Int = {
  var i = 0
  while (hasNext) do {
    if (p(next)) return i
    i += 1
  }
  -1
} expands to def indexWhere(p: (A) => Boolean): Int = {
  var i = 0
  while (hasNext) do {
    if (p(next)) return i
    i += 1
  }
  -1
}
Expansion: def zip[B](that: Iterator[B]): Iterator[(A, B)] = ??? expands to def zip[B](that: Iterator[B]): Iterator[(A, B)] = ???
creating symbol for def hasNext: Boolean in Mode(ImplicitsEnabled)
entered: method hasNext in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A)
creating symbol for def next: A in Mode(ImplicitsEnabled)
entered: method next in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext)
creating symbol for def iterator = this in Mode(ImplicitsEnabled)
entered: method iterator in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next)
creating symbol for def foreach(f: (A) => Unit): Unit = ??? in Mode(ImplicitsEnabled)
entered: method foreach in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator)
creating symbol for def map[B](f: (A) => B): Iterator[B] = ??? in Mode(ImplicitsEnabled)
entered: method map in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator, method foreach)
creating symbol for def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B] = ??? in Mode(ImplicitsEnabled)
entered: method flatMap in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator, method foreach, method map)
creating symbol for def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ??? in Mode(ImplicitsEnabled)
entered: method $plus$plus in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator, method foreach, method map, method flatMap)
creating symbol for def drop(n: Int): Iterator[A] = ??? in Mode(ImplicitsEnabled)
entered: method drop in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator, method foreach, method map, method flatMap, method $plus$plus)
creating symbol for def indexWhere(p: (A) => Boolean): Int = {
  var i = 0
  while (hasNext) do {
    if (p(next)) return i
    i += 1
  }
  -1
} in Mode(ImplicitsEnabled)
entered: method indexWhere in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator, method foreach, method map, method flatMap, method $plus$plus, method drop)
creating symbol for def zip[B](that: Iterator[B]): Iterator[(A, B)] = ??? in Mode(ImplicitsEnabled)
entered: method zip in class Iterator and Scopes(type dotty1$collections$immutable$Iter2$Iterator$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$IterableOnce$$A, method hasNext, method next, method iterator, method foreach, method map, method flatMap, method $plus$plus, method drop, method indexWhere)
ensure first is class dotty1.collections.immutable.Iter2.IterableOnce[
  dotty1$collections$immutable$Iter2$Iterator$$A
] --> Object
typed ident type Boolean in method hasNext
typed ident type A in method next
typed ident type Iterator in method iterator
typed ident type A in method iterator
typed ident type dotty1$collections$immutable$Iter2$IterableOnce$$A in type A
using inherited type for iterator; raw: =>
  dotty1.collections.immutable.Iter2.Iterator[
    dotty1$collections$immutable$Iter2$IterableOnce$$A
  ], inst: =>
  dotty1.collections.immutable.Iter2.Iterator[
    dotty1$collections$immutable$Iter2$IterableOnce$$A
  ], inherited: dotty1.collections.immutable.Iter2.Iterator[
  dotty1$collections$immutable$Iter2$Iterator$$A
]
Expansion: f: (A) => Unit expands to f: (A) => Unit
creating symbol for f: (A) => Unit in Mode(ImplicitsEnabled)
entered: val f in method foreach and Scopes()
typed ident type A in val f
typed ident type Unit in val f
typed ident type Unit in method foreach
typed ident $qmark$qmark$qmark in method foreach
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method map and Scopes()
Expansion: f: (A) => B expands to f: (A) => B
creating symbol for f: (A) => B in Mode(ImplicitsEnabled)
entered: val f in method map and Scopes(type B)
typed ident type A in val f
typed ident type B in val f
typed ident type Iterator in method map
typed ident type B in method map
typed ident $qmark$qmark$qmark in method map
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method flatMap and Scopes()
Expansion: f: (A) => IterableOnce[B] expands to f: (A) => IterableOnce[B]
creating symbol for f: (A) => IterableOnce[B] in Mode(ImplicitsEnabled)
entered: val f in method flatMap and Scopes(type B)
typed ident type A in val f
typed ident type IterableOnce in val f
typed ident type B in val f
typed ident type Iterator in method flatMap
typed ident type B in method flatMap
typed ident $qmark$qmark$qmark in method flatMap
Expansion: B >: A expands to B >: A
creating symbol for B >: A in Mode(ImplicitsEnabled)
entered: type B in method $plus$plus and Scopes()
typed ident type A in type B
Expansion: xs: IterableOnce[B] expands to xs: IterableOnce[B]
creating symbol for xs: IterableOnce[B] in Mode(ImplicitsEnabled)
entered: val xs in method $plus$plus and Scopes(type B)
typed ident type IterableOnce in val xs
typed ident type B in val xs
typed ident type Iterator in method $plus$plus
typed ident type B in method $plus$plus
typed ident $qmark$qmark$qmark in method $plus$plus
Expansion: n: Int expands to n: Int
creating symbol for n: Int in Mode(ImplicitsEnabled)
entered: val n in method drop and Scopes()
typed ident type Int in val n
typed ident type Iterator in method drop
typed ident type A in method drop
typed ident $qmark$qmark$qmark in method drop
Expansion: p: (A) => Boolean expands to p: (A) => Boolean
creating symbol for p: (A) => Boolean in Mode(ImplicitsEnabled)
entered: val p in method indexWhere and Scopes()
typed ident type A in val p
typed ident type Boolean in val p
typed ident type Int in method indexWhere
Expansion: var i = 0 expands to var i = 0
creating symbol for var i = 0 in Mode(ImplicitsEnabled)
entered: val i in method indexWhere and Scopes()
Expansion: <label> def while$(): Unit =
  if (hasNext) {
    {
      if (p(next)) return i
      i += 1
    }
    while$()
  } else () expands to <label> def while$(): Unit =
  if (hasNext) {
    {
      if (p(next)) return i
      i += 1
    }
    while$()
  } else ()
creating symbol for <label> def while$(): Unit =
  if (hasNext) {
    {
      if (p(next)) return i
      i += 1
    }
    while$()
  } else () in Mode(ImplicitsEnabled)
entered: method while$ in method indexWhere and Scopes()
typed ident hasNext in method while$
typed ident p in method while$
typed ident next in method while$
typed ident i in method while$
typed ident i in method while$
adapt to subtype Int(i) !<:< ?{ += : ? }
Expansion: A expands to A
Expansion: C[X] <: Iterable[X] expands to C[X] <: Iterable[X]
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method IterableTransforms and Scopes()
creating symbol for C[X] <: Iterable[X] in Mode(ImplicitsEnabled)
entered: type C in method IterableTransforms and Scopes(type A)
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type C and Scopes()
typed ident type Iterable in type C
Expansion: def <init>[IA]() expands to def <init>[IA]()
creating symbol for def <init>[IA]() in Mode(ImplicitsEnabled)
entered: method <init> in class Iterable and Scopes(type dotty1$collections$immutable$Iter2$Iterable$$IA, type IA)
Expansion: IA expands to IA
creating symbol for IA in Mode(ImplicitsEnabled)
entered: type IA in method <init> and Scopes()
typed ident type IterableOnce in method <init>
typed ident type IA in method <init>
typed ident type dotty1$collections$immutable$Iter2$Iterable$$IA in type IA
typed ident type FromIterator in method <init>
Expansion: def <init>[C[X] <: Iterable[X]]() expands to def <init>[C[X] <: Iterable[X]]()
creating symbol for def <init>[C[X] <: Iterable[X]]() in Mode(ImplicitsEnabled)
entered: method <init> in class FromIterator and Scopes(type dotty1$collections$immutable$Iter2$FromIterator$$C, type C)
Expansion: C[X] <: Iterable[X] expands to C[X] <: Iterable[X]
creating symbol for C[X] <: Iterable[X] in Mode(ImplicitsEnabled)
entered: type C in method <init> and Scopes()
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type C and Scopes()
typed ident type Iterable in type C
typed ident type X in type C
ensure first is class  -->
completing class FromIterator, parents = List(), parentTypes = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object)), parentRefs = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object))
Expansion: def fromIterator[B](it: Iterator[B]): C[B] expands to def fromIterator[B](it: Iterator[B]): C[B]
creating symbol for def fromIterator[B](it: Iterator[B]): C[B] in Mode(ImplicitsEnabled)
entered: method fromIterator in class FromIterator and Scopes(type dotty1$collections$immutable$Iter2$FromIterator$$C, type C, method <init>)
typed ident type Iterable in method <init>
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type dotty1$collections$immutable$Iter2$FromIterator$$C and Scopes()
ensure first is class dotty1.collections.immutable.Iter2.IterableOnce[
  dotty1$collections$immutable$Iter2$Iterable$$IA
], dotty1.collections.immutable.Iter2.FromIterator[
  dotty1.collections.immutable.Iter2.Iterable
] --> Object, Object
completing class Iterable, parents = List(AppliedTypeTree(Ident(IterableOnce),List(Ident(IA))), AppliedTypeTree(Ident(FromIterator),List(Ident(Iterable)))), parentTypes = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),IterableOnce), dotty1$collections$immutable$Iter2$IterableOnce$$A, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Iterable)),dotty1$collections$immutable$Iter2$Iterable$$IA)) | -1982491767), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),FromIterator), dotty1$collections$immutable$Iter2$FromIterator$$C, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Iterable)) | -1977255482)), parentRefs = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),IterableOnce), TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),FromIterator))
typed ident type X in type C
Expansion: c: Iterable[A] & FromIterator[C] expands to c: Iterable[A] & FromIterator[C]
creating symbol for c: Iterable[A] & FromIterator[C] in Mode(ImplicitsEnabled)
entered: val c in method IterableTransforms and Scopes(type A, type C)
typed ident type Iterable in val c
typed ident type A in val c
typed ident type FromIterator in val c
typed ident type C in val c
typed ident type A in method IterableTransforms
typed ident type C in method IterableTransforms
Expansion: def <init>[A, C[X] <: dotty1.collections.immutable.Iter2.Iterable[X]](
  c:
    dotty1.collections.immutable.Iter2.Iterable[A] &
      dotty1.collections.immutable.Iter2.FromIterator[C]
) expands to def <init>[A, C[X] <: dotty1.collections.immutable.Iter2.Iterable[X]](
  c:
    dotty1.collections.immutable.Iter2.Iterable[A] &
      dotty1.collections.immutable.Iter2.FromIterator[C]
)
creating symbol for def <init>[A, C[X] <: dotty1.collections.immutable.Iter2.Iterable[X]](
  c:
    dotty1.collections.immutable.Iter2.Iterable[A] &
      dotty1.collections.immutable.Iter2.FromIterator[C]
) in Mode(ImplicitsEnabled)
entered: method <init> in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c)
Expansion: A expands to A
Expansion: C[X] <: dotty1.collections.immutable.Iter2.Iterable[X] expands to C[X] <: dotty1.collections.immutable.Iter2.Iterable[X]
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
creating symbol for C[X] <: dotty1.collections.immutable.Iter2.Iterable[X] in Mode(ImplicitsEnabled)
entered: type C in method <init> and Scopes(type A)
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type C and Scopes()
typed ident type Iterable in type C
typed ident type X in type C
Expansion: c:
  dotty1.collections.immutable.Iter2.Iterable[A] &
    dotty1.collections.immutable.Iter2.FromIterator[C] expands to c:
  dotty1.collections.immutable.Iter2.Iterable[A] &
    dotty1.collections.immutable.Iter2.FromIterator[C]
creating symbol for c:
  dotty1.collections.immutable.Iter2.Iterable[A] &
    dotty1.collections.immutable.Iter2.FromIterator[C] in Mode(ImplicitsEnabled)
entered: val c in method <init> and Scopes(type A, type C)
typed ident type Iterable in val c
typed ident type A in val c
typed ident type FromIterator in val c
typed ident type C in val c
typed ident type AnyVal in method <init>
completing class IterableTransforms, parents = List(Ident(AnyVal)), parentTypes = List(TypeRef(TermRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,<root>)),scala),AnyVal)), parentRefs = List(TypeRef(TermRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,<root>)),scala),AnyVal))
Expansion: def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f)) expands to def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f))
Expansion: def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
  c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator)) expands to def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
  c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator))
Expansion: def ++[B >: A](xs: IterableOnce[B]): C[B] =
  c.fromIterator(c.buildIterator ++ xs.buildIterator) expands to def ++[B >: A](xs: IterableOnce[B]): C[B] =
  c.fromIterator(c.buildIterator ++ xs.buildIterator)
Expansion: def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n)) expands to def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n))
Expansion: def head: A = c.iterator.next expands to def head: A = c.iterator.next
Expansion: def zip[B](xs: IterableOnce[B]): C[(A, B)] =
  c.fromIterator(c.iterator.zip(xs.iterator)) expands to def zip[B](xs: IterableOnce[B]): C[(A, B)] =
  c.fromIterator(c.iterator.zip(xs.iterator))
creating symbol for def map[B](f: (A) => B): C[B] = c.fromIterator(c.buildIterator.map(f)) in Mode(ImplicitsEnabled)
entered: method map in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c, method <init>)
creating symbol for def flatMap[B](f: (A) => IterableOnce[B]): C[B] =
  c.fromIterator(c.buildIterator.flatMap(_$1 => f(_$1).buildIterator)) in Mode(ImplicitsEnabled)
entered: method flatMap in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c, method <init>, method map)
creating symbol for def ++[B >: A](xs: IterableOnce[B]): C[B] =
  c.fromIterator(c.buildIterator ++ xs.buildIterator) in Mode(ImplicitsEnabled)
entered: method $plus$plus in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c, method <init>, method map, method flatMap)
creating symbol for def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n)) in Mode(ImplicitsEnabled)
entered: method drop in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c, method <init>, method map, method flatMap, method $plus$plus)
creating symbol for def head: A = c.iterator.next in Mode(ImplicitsEnabled)
entered: method head in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c, method <init>, method map, method flatMap, method $plus$plus, method drop)
creating symbol for def zip[B](xs: IterableOnce[B]): C[(A, B)] =
  c.fromIterator(c.iterator.zip(xs.iterator)) in Mode(ImplicitsEnabled)
entered: method zip in class IterableTransforms and Scopes(type dotty1$collections$immutable$Iter2$IterableTransforms$$A, type A, type dotty1$collections$immutable$Iter2$IterableTransforms$$C, type C, val c, method <init>, method map, method flatMap, method $plus$plus, method drop, method head)
typed ident type dotty1$collections$immutable$Iter2$IterableTransforms$$A in type A
typed ident type dotty1$collections$immutable$Iter2$IterableTransforms$$C in type C
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type dotty1$collections$immutable$Iter2$IterableTransforms$$C and Scopes()
Expansion: SA expands to SA
Expansion: C[X] <: Seq[X] expands to C[X] <: Seq[X]
creating symbol for SA in Mode(ImplicitsEnabled)
entered: type SA in method SeqTransforms and Scopes()
creating symbol for C[X] <: Seq[X] in Mode(ImplicitsEnabled)
entered: type C in method SeqTransforms and Scopes(type SA)
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type C and Scopes()
typed ident type Seq in type C
Expansion: def <init>[AA]() expands to def <init>[AA]()
creating symbol for def <init>[AA]() in Mode(ImplicitsEnabled)
entered: method <init> in class Seq and Scopes(type dotty1$collections$immutable$Iter2$Seq$$AA, type AA)
Expansion: AA expands to AA
creating symbol for AA in Mode(ImplicitsEnabled)
entered: type AA in method <init> and Scopes()
typed ident type Iterable in method <init>
typed ident type AA in method <init>
typed ident type dotty1$collections$immutable$Iter2$Seq$$AA in type AA
typed ident type FromIterator in method <init>
typed ident type Seq in method <init>
ensure first is class dotty1.collections.immutable.Iter2.Iterable[
  dotty1$collections$immutable$Iter2$Seq$$AA
], dotty1.collections.immutable.Iter2.FromIterator[[hk$0] =>
  dotty1.collections.immutable.Iter2.Seq[hk$0]
] --> Object, Object
completing class Seq, parents = List(AppliedTypeTree(Ident(Iterable),List(Ident(AA))), AppliedTypeTree(Ident(FromIterator),List(Ident(Seq)))), parentTypes = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Iterable), dotty1$collections$immutable$Iter2$Iterable$$IA, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Seq)),dotty1$collections$immutable$Iter2$Seq$$AA)) | 2108425480), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),FromIterator), dotty1$collections$immutable$Iter2$FromIterator$$C, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Lambda$I), $apply, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Seq), dotty1$collections$immutable$Iter2$Seq$$AA, TypeAlias(TypeRef(RefinedThis(-1356912209),hk$0)) | -1140118804)) | -1356912209)) | -1449470020)), parentRefs = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Iterable), TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),FromIterator))
Expansion: def apply(i: Int): AA expands to def apply(i: Int): AA
Expansion: def length: Int expands to def length: Int
creating symbol for def apply(i: Int): AA in Mode(ImplicitsEnabled)
entered: method apply in class Seq and Scopes(type dotty1$collections$immutable$Iter2$Seq$$AA, type AA, method <init>, type dotty1$collections$immutable$Iter2$Iterable$$IA, type dotty1$collections$immutable$Iter2$FromIterator$$C)
creating symbol for def length: Int in Mode(ImplicitsEnabled)
entered: method length in class Seq and Scopes(type dotty1$collections$immutable$Iter2$Seq$$AA, type AA, method <init>, type dotty1$collections$immutable$Iter2$Iterable$$IA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method apply)
typed ident type X in type C
Expansion: c: Seq[SA] & FromIterator[C] expands to c: Seq[SA] & FromIterator[C]
creating symbol for c: Seq[SA] & FromIterator[C] in Mode(ImplicitsEnabled)
entered: val c in method SeqTransforms and Scopes(type SA, type C)
typed ident type Seq in val c
typed ident type SA in val c
typed ident type FromIterator in val c
typed ident type C in val c
typed ident type SA in method SeqTransforms
typed ident type C in method SeqTransforms
Expansion: def <init>[SA, C[X] <: dotty1.collections.immutable.Iter2.Seq[X]](
  c:
    dotty1.collections.immutable.Iter2.Seq[SA] &
      dotty1.collections.immutable.Iter2.FromIterator[C]
) expands to def <init>[SA, C[X] <: dotty1.collections.immutable.Iter2.Seq[X]](
  c:
    dotty1.collections.immutable.Iter2.Seq[SA] &
      dotty1.collections.immutable.Iter2.FromIterator[C]
)
creating symbol for def <init>[SA, C[X] <: dotty1.collections.immutable.Iter2.Seq[X]](
  c:
    dotty1.collections.immutable.Iter2.Seq[SA] &
      dotty1.collections.immutable.Iter2.FromIterator[C]
) in Mode(ImplicitsEnabled)
entered: method <init> in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA, type SA, type dotty1$collections$immutable$Iter2$SeqTransforms$$C, type C, val c)
Expansion: SA expands to SA
Expansion: C[X] <: dotty1.collections.immutable.Iter2.Seq[X] expands to C[X] <: dotty1.collections.immutable.Iter2.Seq[X]
creating symbol for SA in Mode(ImplicitsEnabled)
entered: type SA in method <init> and Scopes()
creating symbol for C[X] <: dotty1.collections.immutable.Iter2.Seq[X] in Mode(ImplicitsEnabled)
entered: type C in method <init> and Scopes(type SA)
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type C and Scopes()
typed ident type Seq in type C
typed ident type X in type C
Expansion: c:
  dotty1.collections.immutable.Iter2.Seq[SA] &
    dotty1.collections.immutable.Iter2.FromIterator[C] expands to c:
  dotty1.collections.immutable.Iter2.Seq[SA] &
    dotty1.collections.immutable.Iter2.FromIterator[C]
creating symbol for c:
  dotty1.collections.immutable.Iter2.Seq[SA] &
    dotty1.collections.immutable.Iter2.FromIterator[C] in Mode(ImplicitsEnabled)
entered: val c in method <init> and Scopes(type SA, type C)
typed ident type Seq in val c
typed ident type SA in val c
typed ident type FromIterator in val c
typed ident type C in val c
typed ident type AnyVal in method <init>
completing class SeqTransforms, parents = List(Ident(AnyVal)), parentTypes = List(TypeRef(TermRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,<root>)),scala),AnyVal)), parentRefs = List(TypeRef(TermRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,<root>)),scala),AnyVal))
Expansion: def reverse: C[SA] = {
  val elems = new Array[AnyRef](c.length)
  var i = elems.length
  val it = c.iterator
  while (it.hasNext) do {
    i -= 1
    elems(i) = it.next.asInstanceOf[AnyRef]
  }
  val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
  xzz
} expands to def reverse: C[SA] = {
  val elems = new Array[AnyRef](c.length)
  var i = elems.length
  val it = c.iterator
  while (it.hasNext) do {
    i -= 1
    elems(i) = it.next.asInstanceOf[AnyRef]
  }
  val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
  xzz
}
Expansion: def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p) expands to def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p)
creating symbol for def reverse: C[SA] = {
  val elems = new Array[AnyRef](c.length)
  var i = elems.length
  val it = c.iterator
  while (it.hasNext) do {
    i -= 1
    elems(i) = it.next.asInstanceOf[AnyRef]
  }
  val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length))
  xzz
} in Mode(ImplicitsEnabled)
entered: method reverse in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA, type SA, type dotty1$collections$immutable$Iter2$SeqTransforms$$C, type C, val c, method <init>)
creating symbol for def indexWhere(p: (SA) => Boolean): Int = c.iterator.indexWhere(p) in Mode(ImplicitsEnabled)
entered: method indexWhere in class SeqTransforms and Scopes(type dotty1$collections$immutable$Iter2$SeqTransforms$$SA, type SA, type dotty1$collections$immutable$Iter2$SeqTransforms$$C, type C, val c, method <init>, method reverse)
typed ident type dotty1$collections$immutable$Iter2$SeqTransforms$$SA in type SA
typed ident type dotty1$collections$immutable$Iter2$SeqTransforms$$C in type C
Expansion: X expands to X
creating symbol for X in Mode(ImplicitsEnabled)
entered: type X in type dotty1$collections$immutable$Iter2$SeqTransforms$$C and Scopes()
>>>> StoredError: += is not a member of Int
typed ident i in method while$
adapt overloaded <overloaded Int#+> with alternatives (x: Double)Double, (x: Float)Float, (x: Long)Long, (x: Int)Int, (x: Char)Int, (x: Short)Int, (x: Byte)Int, (x: String)String
typed ident while$ in method while$
typed ident while$ in method indexWhere
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method zip and Scopes()
Expansion: that: Iterator[B] expands to that: Iterator[B]
creating symbol for that: Iterator[B] in Mode(ImplicitsEnabled)
entered: val that in method zip and Scopes(type B)
typed ident type Iterator in val that
typed ident type B in val that
typed ident type Iterator in method zip
typed ident type A in method zip
typed ident type B in method zip
typed ident $qmark$qmark$qmark in method zip
check no double defs trait Iterator
ensure first is class  -->
typed ident type Iterator in method buildIterator
typed ident type A in method buildIterator
typed ident iterator in method buildIterator
check no double defs trait IterableOnce
ensure first is class  -->
typed ident type dotty1$collections$immutable$Iter2$FromIterator$$C in type C
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method fromIterator and Scopes()
Expansion: it: Iterator[B] expands to it: Iterator[B]
creating symbol for it: Iterator[B] in Mode(ImplicitsEnabled)
entered: val it in method fromIterator and Scopes(type B)
typed ident type Iterator in val it
typed ident type B in val it
typed ident type C in method fromIterator
typed ident type B in method fromIterator
check no double defs trait FromIterator
ensure first is class dotty1.collections.immutable.Iter2.IterableOnce[
  dotty1$collections$immutable$Iter2$Iterable$$IA
], dotty1.collections.immutable.Iter2.FromIterator[
  dotty1.collections.immutable.Iter2.Iterable
] --> Object, Object
check no double defs trait Iterable
ensure first is class dotty1.collections.immutable.Iter2.Iterable[
  dotty1$collections$immutable$Iter2$Seq$$AA
], dotty1.collections.immutable.Iter2.FromIterator[[hk$0] =>
  dotty1.collections.immutable.Iter2.Seq[hk$0]
] --> Object, Object
Expansion: i: Int expands to i: Int
creating symbol for i: Int in Mode(ImplicitsEnabled)
entered: val i in method apply and Scopes()
typed ident type Int in val i
typed ident type AA in method apply
typed ident type Int in method length
check no double defs trait Seq
Expansion: def <init>[A]() expands to def <init>[A]()
creating symbol for def <init>[A]() in Mode(ImplicitsEnabled)
entered: method <init> in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
typed ident type Seq in method <init>
typed ident type A in method <init>
typed ident type dotty1$collections$immutable$Iter2$List$$A in type A
typed ident type FromIterator in method <init>
typed ident type List in method <init>
ensure first is class dotty1.collections.immutable.Iter2.Seq[
  dotty1$collections$immutable$Iter2$List$$A
], dotty1.collections.immutable.Iter2.FromIterator[[hk$0] =>
  dotty1.collections.immutable.Iter2.List[hk$0]
] --> Object, Object
completing class List, parents = List(AppliedTypeTree(Ident(Seq),List(Ident(A))), AppliedTypeTree(Ident(FromIterator),List(Ident(List)))), parentTypes = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Seq), dotty1$collections$immutable$Iter2$Seq$$AA, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),List)),dotty1$collections$immutable$Iter2$List$$A)) | 225871882), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),FromIterator), dotty1$collections$immutable$Iter2$FromIterator$$C, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Lambda$I), $apply, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),List), dotty1$collections$immutable$Iter2$List$$A, TypeAlias(TypeRef(RefinedThis(570850621),hk$0)) | -1982301617)) | 570850621)) | -841483479)), parentRefs = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Seq), TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),FromIterator))
Expansion: def isEmpty: Boolean expands to def isEmpty: Boolean
Expansion: def head: A expands to def head: A
Expansion: def tail: List[A] expands to def tail: List[A]
Expansion: def iterator = new ListIterator[A](this) expands to def iterator = new ListIterator[A](this)
Expansion: def fromIterator[B](it: Iterator[B]): List[B] =
  it match {
    case ListIterator(xs) =>
      xs
    case _ =>
      if (it.hasNext) Cons(it.next, fromIterator(it)) else
        Nil.asInstanceOf[List[B]]
  } expands to def fromIterator[B](it: Iterator[B]): List[B] =
  it match {
    case ListIterator(xs) =>
      xs
    case _ =>
      if (it.hasNext) Cons(it.next, fromIterator(it)) else
        Nil.asInstanceOf[List[B]]
  }
Expansion: def apply(i: Int): A = {
  require(! isEmpty)
  if (i == 0) head else tail.apply(i - 1)
} expands to def apply(i: Int): A = {
  require(! isEmpty)
  if (i == 0) head else tail.apply(i - 1)
}
Expansion: def length: Int = if (isEmpty) 0 else 1 + tail.length expands to def length: Int = if (isEmpty) 0 else 1 + tail.length
creating symbol for def isEmpty: Boolean in Mode(ImplicitsEnabled)
entered: method isEmpty in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C)
creating symbol for def head: A in Mode(ImplicitsEnabled)
entered: method head in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method isEmpty)
creating symbol for def tail: List[A] in Mode(ImplicitsEnabled)
entered: method tail in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method isEmpty, method head)
creating symbol for def iterator = new ListIterator[A](this) in Mode(ImplicitsEnabled)
entered: method iterator in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method isEmpty, method head, method tail)
creating symbol for def fromIterator[B](it: Iterator[B]): List[B] =
  it match {
    case ListIterator(xs) =>
      xs
    case _ =>
      if (it.hasNext) Cons(it.next, fromIterator(it)) else
        Nil.asInstanceOf[List[B]]
  } in Mode(ImplicitsEnabled)
entered: method fromIterator in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method isEmpty, method head, method tail, method iterator)
creating symbol for def apply(i: Int): A = {
  require(! isEmpty)
  if (i == 0) head else tail.apply(i - 1)
} in Mode(ImplicitsEnabled)
entered: method apply in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method isEmpty, method head, method tail, method iterator, method fromIterator)
creating symbol for def length: Int = if (isEmpty) 0 else 1 + tail.length in Mode(ImplicitsEnabled)
entered: method length in class List and Scopes(type dotty1$collections$immutable$Iter2$List$$A, type A, method <init>, type dotty1$collections$immutable$Iter2$Seq$$AA, type dotty1$collections$immutable$Iter2$FromIterator$$C, method isEmpty, method head, method tail, method iterator, method fromIterator, method apply)
ensure first is class dotty1.collections.immutable.Iter2.Seq[
  dotty1$collections$immutable$Iter2$List$$A
], dotty1.collections.immutable.Iter2.FromIterator[[hk$0] =>
  dotty1.collections.immutable.Iter2.List[hk$0]
] --> Object, Object
typed ident type Boolean in method isEmpty
typed ident type A in method head
typed ident type List in method tail
typed ident type A in method tail
using inherited type for iterator; raw: =>
  dotty1.collections.immutable.Iter2.Iterator[
    dotty1$collections$immutable$Iter2$IterableOnce$$A
  ], inst: =>
  dotty1.collections.immutable.Iter2.Iterator[
    dotty1$collections$immutable$Iter2$IterableOnce$$A
  ], inherited: dotty1.collections.immutable.Iter2.Iterator[
  dotty1$collections$immutable$Iter2$List$$A
]
typed ident type ListIterator in method iterator
Expansion: def <init>[A](xs: List[A]) expands to def <init>[A](xs: List[A])
creating symbol for def <init>[A](xs: List[A]) in Mode(ImplicitsEnabled)
entered: method <init> in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
Expansion: xs: List[A] expands to xs: List[A]
creating symbol for xs: List[A] in Mode(ImplicitsEnabled)
entered: val xs in method <init> and Scopes(type A)
typed ident type List in val xs
typed ident type A in val xs
typed ident type Iterator in method <init>
typed ident type A in method <init>
typed ident type dotty1$collections$immutable$Iter2$ListIterator$$A in type A
typed ident type List in method <init>
typed ident type A in method <init>
ensure first is class dotty1.collections.immutable.Iter2.Iterator[
  dotty1$collections$immutable$Iter2$ListIterator$$A
], Product1[
  dotty1.collections.immutable.Iter2.List[
    dotty1$collections$immutable$Iter2$ListIterator$$A
  ]
] --> Object, <notype>
completing class ListIterator, parents = List(AppliedTypeTree(Ident(Iterator),List(Ident(A))), AppliedTypeTree(TypedSplice(TypeTree[TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Product1)]),List(AppliedTypeTree(Ident(List),List(Ident(A)))))), parentTypes = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Iterator), dotty1$collections$immutable$Iter2$Iterator$$A, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),ListIterator)),dotty1$collections$immutable$Iter2$ListIterator$$A)) | -714816279), RefinedType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Product1), scala$Product1$$T1, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),List), dotty1$collections$immutable$Iter2$List$$A, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),ListIterator)),dotty1$collections$immutable$Iter2$ListIterator$$A)) | 253055211)) | -103786273)), parentRefs = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Iterator), TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Product1))
Expansion: private[this] var current: List[A] = xs expands to private[this] var current: List[A] = xs
Expansion: def hasNext = ! current.isEmpty expands to def hasNext = ! current.isEmpty
Expansion: def next = {
  val res = current.head
  current = current.tail
  res
} expands to def next = {
  val res = current.head
  current = current.tail
  res
}
Expansion: def copy[A](xs = xs @scala.annotation.unchecked.uncheckedVariance()) =
  new
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >
  [...](...) expands to Thicket {
  def copy[A](xs) =
    new
      <derived typetree watching
        case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
          A
          val xs
          private[this] var current: ... = ...
          def hasNext = ...
          def next = ...
          def copy[...](...) = ...
          def isDefined = ...
          def _1 = ...
        }
      >
    [...](...)
  def copy$default$1[...] = ...
 }
Expansion: def isDefined = true expands to def isDefined = true
Expansion: def _1 = this.xs expands to def _1 = this.xs
creating symbol for private[this] var current: List[A] = xs in Mode(ImplicitsEnabled)
entered: val current in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1)
creating symbol for def hasNext = ! current.isEmpty in Mode(ImplicitsEnabled)
entered: method hasNext in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1, val current)
creating symbol for def next = {
  val res = current.head
  current = current.tail
  res
} in Mode(ImplicitsEnabled)
entered: method next in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1, val current, method hasNext)
creating symbol for def copy[A](xs) =
  new
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >
  [...](...) in Mode(ImplicitsEnabled)
entered: method copy in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1, val current, method hasNext, method next)
creating symbol for def copy$default$1[A] = xs @scala.annotation.unchecked.uncheckedVariance() in Mode(ImplicitsEnabled)
entered: method copy$default$1 in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1, val current, method hasNext, method next, method copy)
creating symbol for def isDefined = true in Mode(ImplicitsEnabled)
entered: method isDefined in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1, val current, method hasNext, method next, method copy, method copy$default$1)
creating symbol for def _1 = this.xs in Mode(ImplicitsEnabled)
entered: method _1 in class ListIterator and Scopes(type dotty1$collections$immutable$Iter2$ListIterator$$A, type A, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$Iterator$$A, type scala$Product1$$T1, val current, method hasNext, method next, method copy, method copy$default$1, method isDefined)
typed ident type A in method iterator
Expansion: B expands to B
creating symbol for B in Mode(ImplicitsEnabled)
entered: type B in method fromIterator and Scopes()
Expansion: it: Iterator[B] expands to it: Iterator[B]
creating symbol for it: Iterator[B] in Mode(ImplicitsEnabled)
entered: val it in method fromIterator and Scopes(type B)
typed ident type Iterator in val it
typed ident type B in val it
typed ident type List in method fromIterator
typed ident type B in method fromIterator
typed ident it in method fromIterator
typed ident ListIterator in method fromIterator
Expansion: def <init>() expands to def <init>()
creating symbol for def <init>() in Mode(ImplicitsEnabled)
entered: method <init> in module class ListIterator$ and Scopes(method companion$class)
completing module class ListIterator$, parents = List(TypedSplice(TypeTree[TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),AnyRef)])), parentTypes = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),AnyRef)), parentRefs = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object))
Expansion: def apply[A](xs) =
  new
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >
  [...](...) expands to def apply[A](xs) =
  new
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >
  [...](...)
Expansion: def unapply[A](
  x$1:
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >[...]
) = x$1 expands to def unapply[A](
  x$1:
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >[...]
) = x$1
creating symbol for def apply[A](xs) =
  new
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >
  [...](...) in Mode(ImplicitsEnabled)
entered: method apply in module class ListIterator$ and Scopes(method companion$class, method <init>)
creating symbol for def unapply[A](
  x$1:
    <derived typetree watching
      case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
        A
        val xs
        private[this] var current: ... = ...
        def hasNext = ...
        def next = ...
        def copy[...](...) = ...
        def isDefined = ...
        def _1 = ...
      }
    >[...]
) = x$1 in Mode(ImplicitsEnabled)
entered: method unapply in module class ListIterator$ and Scopes(method companion$class, method <init>, method apply)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method unapply and Scopes()
Expansion: x$1:
  <derived typetree watching
    case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
      A
      val xs
      private[this] var current: ... = ...
      def hasNext = ...
      def next = ...
      def copy[...](...) = ...
      def isDefined = ...
      def _1 = ...
    }
  >[...] expands to x$1:
  <derived typetree watching
    case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
      A
      val xs
      private[this] var current: ... = ...
      def hasNext = ...
      def next = ...
      def copy[...](...) = ...
      def isDefined = ...
      def _1 = ...
    }
  >[...]
creating symbol for x$1:
  <derived typetree watching
    case class ListIterator[A...](xs: ...) extends ...[...] with ...[...] {
      A
      val xs
      private[this] var current: ... = ...
      def hasNext = ...
      def next = ...
      def copy[...](...) = ...
      def isDefined = ...
      def _1 = ...
    }
  >[...] in Mode(ImplicitsEnabled)
entered: val x$1 in method unapply and Scopes(type A)
typed ident type A in val x$1
typed ident x$1 in method unapply
narrow gadt bound of type B: TypeBounds(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Nothing), TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Any)) from above to TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Nothing) false
narrow gadt bound of type B: TypeBounds(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Nothing), TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Any)) from below to TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Any) false
approx A, from below = false, bound = B, inst = B
instantiating (A? <: B) with B
using inherited type for _1; raw: => scala$Product1$$T1, inst: => scala$Product1$$T1, inherited: dotty1.collections.immutable.Iter2.List[
  dotty1$collections$immutable$Iter2$ListIterator$$A
]
typed ident xs in method fromIterator
typed ident _ in method fromIterator
typed bind xs @ _ pt = dotty1.collections.immutable.Iter2.List[B] bodytpe = dotty1.collections.immutable.Iter2.List[B]
typed ident xs in method fromIterator
typed ident _ in method fromIterator
typed ident it in method fromIterator
typed ident Cons in method fromIterator
Expansion: def <init>() expands to def <init>()
creating symbol for def <init>() in Mode(ImplicitsEnabled)
entered: method <init> in module class Cons$ and Scopes(method companion$class)
completing module class Cons$, parents = List(TypedSplice(TypeTree[TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),AnyRef)])), parentTypes = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),AnyRef)), parentRefs = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object))
Expansion: def apply[A](x, xs) =
  new
    <derived typetree watching
      case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[..., ...]

{
        A
        val x
        val xs
        def isEmpty = ...
        def head = ...
        def tail = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >
  [...](..., ...) in Mode(ImplicitsEnabled)
entered: method apply in module class Cons$ and Scopes(method companion$class, method <init>)
creating symbol for def unapply[A](
  x$1:
    <derived typetree watching
      case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[..., ...]

{
        A
        val x
        val xs
        def isEmpty = ...
        def head = ...
        def tail = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >[...]
) = x$1 in Mode(ImplicitsEnabled)
entered: method unapply in module class Cons$ and Scopes(method companion$class, method <init>, method apply)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method apply and Scopes()
Expansion: def <init>[A](x: A, xs: List[A]) expands to def <init>[A](x: A, xs: List[A])
creating symbol for def <init>[A](x: A, xs: List[A]) in Mode(ImplicitsEnabled)
entered: method <init> in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A, val x, val xs, method companion$module)
Expansion: A expands to A
creating symbol for A in Mode(ImplicitsEnabled)
entered: type A in method <init> and Scopes()
Expansion: x: A expands to x: A
Expansion: xs: List[A] expands to xs: List[A]
creating symbol for x: A in Mode(ImplicitsEnabled)
entered: val x in method <init> and Scopes(type A)
creating symbol for xs: List[A] in Mode(ImplicitsEnabled)
entered: val xs in method <init> and Scopes(type A, val x)
typed ident type A in val x
typed ident type List in val xs
typed ident type A in val xs
typed ident type List in method <init>
typed ident type A in method <init>
typed ident type dotty1$collections$immutable$Iter2$Cons$$A in type A
typed ident type A in method <init>
typed ident type List in method <init>
typed ident type A in method <init>
ensure first is class dotty1.collections.immutable.Iter2.List[
  dotty1$collections$immutable$Iter2$Cons$$A
], Product2[dotty1$collections$immutable$Iter2$Cons$$A,
  dotty1.collections.immutable.Iter2.List[
    dotty1$collections$immutable$Iter2$Cons$$A
  ]
] --> Object, <notype>
completing class Cons, parents = List(AppliedTypeTree(Ident(List),List(Ident(A))), AppliedTypeTree(TypedSplice(TypeTree[TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Product2)]),List(Ident(A), AppliedTypeTree(Ident(List),List(Ident(A)))))), parentTypes = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object), RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),List), dotty1$collections$immutable$Iter2$List$$A, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Cons)),dotty1$collections$immutable$Iter2$Cons$$A)) | -2059067099), RefinedType(RefinedType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Product2), scala$Product2$$T1, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Cons)),dotty1$collections$immutable$Iter2$Cons$$A)) | -1378492923), scala$Product2$$T2, TypeAlias(RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),List), dotty1$collections$immutable$Iter2$List$$A, TypeAlias(TypeRef(ThisType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),Cons)),dotty1$collections$immutable$Iter2$Cons$$A)) | -2059067099)) | -955328987)), parentRefs = List(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,lang)),Object), TypeRef(ThisType(TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,immutable)),Iter2$)),List), TypeRef(ThisType(TypeRef(dotty.tools.dotc.core.Types$NoPrefix$@28ba21f3,scala)),Product2))
Expansion: def isEmpty = false expands to def isEmpty = false
Expansion: def head = x expands to def head = x
Expansion: def tail = xs expands to def tail = xs
Expansion: def copy[A](x = x @scala.annotation.unchecked.uncheckedVariance(),
  xs = xs @scala.annotation.unchecked.uncheckedVariance()
) =
  new
    <derived typetree watching
      case class Cons[A...](x: ..., xs: ...) extends ...[...] with ...[..., ...]

{
        A
        val x
        val xs
        def isEmpty = ...
        def head = ...
        def tail = ...
        def copy[...](..., ...) = ...
        def isDefined = ...
        def _1 = ...
        def _2 = ...
      }
    >
  [...](..., ...) in Mode(ImplicitsEnabled)
entered: method copy in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A, val x, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$List$$A, type scala$Product2$$T2, type scala$Product2$$T1, method isEmpty, method head, method tail)
creating symbol for def copy$default$1[A] = x @scala.annotation.unchecked.uncheckedVariance() in Mode(ImplicitsEnabled)
entered: method copy$default$1 in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A, val x, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$List$$A, type scala$Product2$$T2, type scala$Product2$$T1, method isEmpty, method head, method tail, method copy)
creating symbol for def copy$default$2[A] = xs @scala.annotation.unchecked.uncheckedVariance() in Mode(ImplicitsEnabled)
entered: method copy$default$2 in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A, val x, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$List$$A, type scala$Product2$$T2, type scala$Product2$$T1, method isEmpty, method head, method tail, method copy, method copy$default$1)
creating symbol for def isDefined = true in Mode(ImplicitsEnabled)
entered: method isDefined in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A, val x, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$List$$A, type scala$Product2$$T2, type scala$Product2$$T1, method isEmpty, method head, method tail, method copy, method copy$default$1, method copy$default$2)
creating symbol for def _1 = this.x in Mode(ImplicitsEnabled)
entered: method _1 in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A, val x, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$List$$A, type scala$Product2$$T2, type scala$Product2$$T1, method isEmpty, method head, method tail, method copy, method copy$default$1, method copy$default$2, method isDefined)
creating symbol for def _2 = this.xs in Mode(ImplicitsEnabled)
entered: method _2 in class Cons and Scopes(type dotty1$collections$immutable$Iter2$Cons$$A, type A, val x, val xs, method companion$module, method <init>, type dotty1$collections$immutable$Iter2$List$$A, type scala$Product2$$T2, type scala$Product2$$T1, method isEmpty, method head, method tail, method copy, method copy$default$1, method copy$default$2, method isDefined, method _1)
Expansion: x expands to x
Expansion: xs expands to xs
creating symbol for x in Mode(ImplicitsEnabled)
entered: val x in method apply and Scopes(type A)
creating symbol for xs in Mode(ImplicitsEnabled)
entered: val xs in method apply and Scopes(type A, val x)
typed ident type A in method apply
typed ident x in method apply
typed ident xs in method apply
typed ident it in method fromIterator
typed ident fromIterator in method fromIterator
exception occurred while typechecking Iter3.scala
exception occurred while compiling Iter3.scala
Exception in thread "main" java.lang.ClassCastException: dotty.tools.dotc.core.Types$PolyParam cannot be cast to dotty.tools.dotc.core.Types$TypeBounds
        at dotty.tools.dotc.core.OrderingConstraint.nonParamBounds(OrderingConstraint.scala:193)
        at dotty.tools.dotc.core.OrderingConstraint.narrowBound(OrderingConstraint.scala:356)
        at dotty.tools.dotc.core.OrderingConstraint.narrowBound(OrderingConstraint.scala:126)
        at dotty.tools.dotc.core.ConstraintHandling.addOneBound(ConstraintHandling.scala:38)
        at dotty.tools.dotc.core.ConstraintHandling.$anonfun$unify$1(ConstraintHandling.scala:105)
        at dotty.tools.dotc.core.ConstraintHandling$$Lambda$806/1131040331.apply(Unknown Source)
        at scala.collection.LinearSeqOptimized$class.forall(LinearSeqOptimized.scala:83)
        at scala.collection.immutable.List.forall(List.scala:84)
        at dotty.tools.dotc.core.ConstraintHandling.unify(ConstraintHandling.scala:105)
        at dotty.tools.dotc.core.ConstraintHandling.addLess(ConstraintHandling.scala:76)
        at dotty.tools.dotc.core.TypeComparer.addLess(TypeComparer.scala:19)
        at dotty.tools.dotc.core.ConstraintHandling.liftedTree1$1(ConstraintHandling.scala:227)
        at dotty.tools.dotc.core.ConstraintHandling.addConstraint(ConstraintHandling.scala:225)
        at dotty.tools.dotc.core.TypeComparer.addConstraint(TypeComparer.scala:19)
        at dotty.tools.dotc.core.TypeComparer.comparePolyParam$1(TypeComparer.scala:255)
        at dotty.tools.dotc.core.TypeComparer.secondTry(TypeComparer.scala:258)
        at dotty.tools.dotc.core.TypeComparer.firstTry(TypeComparer.scala:177)
        at dotty.tools.dotc.core.TypeComparer.liftedTree3$1(TypeComparer.scala:100)
        at dotty.tools.dotc.core.TypeComparer.$anonfun$isSubType$3(TypeComparer.scala:97)
        at dotty.tools.dotc.core.TypeComparer$$Lambda$435/2009787198.apply$mcZ$sp(Unknown Source)
        at scala.compat.java8.JFunction0$mcZ$sp.apply(JFunction0$mcZ$sp.java:12)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:148)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.core.TypeComparer.isSubType(TypeComparer.scala:91)
        at dotty.tools.dotc.core.TypeComparer.secondTry(TypeComparer.scala:272)
        at dotty.tools.dotc.core.TypeComparer.firstTry(TypeComparer.scala:177)
        at dotty.tools.dotc.core.TypeComparer.liftedTree3$1(TypeComparer.scala:100)
        at dotty.tools.dotc.core.TypeComparer.$anonfun$isSubType$3(TypeComparer.scala:97)
        at dotty.tools.dotc.core.TypeComparer$$Lambda$435/2009787198.apply$mcZ$sp(Unknown Source)
        at scala.compat.java8.JFunction0$mcZ$sp.apply(JFunction0$mcZ$sp.java:12)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:148)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.core.TypeComparer.isSubType(TypeComparer.scala:91)
        at dotty.tools.dotc.core.TypeComparer.firstTry(TypeComparer.scala:179)
        at dotty.tools.dotc.core.TypeComparer.liftedTree3$1(TypeComparer.scala:100)
        at dotty.tools.dotc.core.TypeComparer.$anonfun$isSubType$3(TypeComparer.scala:97)
        at dotty.tools.dotc.core.TypeComparer$$Lambda$435/2009787198.apply$mcZ$sp(Unknown Source)
        at scala.compat.java8.JFunction0$mcZ$sp.apply(JFunction0$mcZ$sp.java:12)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:148)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.core.TypeComparer.isSubType(TypeComparer.scala:91)
        at dotty.tools.dotc.core.TypeComparer.compareTypeBounds$1(TypeComparer.scala:401)
        at dotty.tools.dotc.core.TypeComparer.thirdTry(TypeComparer.scala:408)
        at dotty.tools.dotc.core.TypeComparer.secondTry(TypeComparer.scala:291)
        at dotty.tools.dotc.core.TypeComparer.firstTry(TypeComparer.scala:232)
        at dotty.tools.dotc.core.TypeComparer.liftedTree3$1(TypeComparer.scala:100)
        at dotty.tools.dotc.core.TypeComparer.$anonfun$isSubType$3(TypeComparer.scala:97)
        at dotty.tools.dotc.core.TypeComparer$$Lambda$435/2009787198.apply$mcZ$sp(Unknown Source)
        at scala.compat.java8.JFunction0$mcZ$sp.apply(JFunction0$mcZ$sp.java:12)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:148)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.core.TypeComparer.isSubType(TypeComparer.scala:91)
        at dotty.tools.dotc.core.TypeComparer.isSubRefinements(TypeComparer.scala:616)
        at dotty.tools.dotc.core.TypeComparer.compareRefined$1(TypeComparer.scala:344)
        at dotty.tools.dotc.core.TypeComparer.thirdTry(TypeComparer.scala:346)
        at dotty.tools.dotc.core.TypeComparer.secondTry(TypeComparer.scala:291)
        at dotty.tools.dotc.core.TypeComparer.firstTry(TypeComparer.scala:232)
        at dotty.tools.dotc.core.TypeComparer.liftedTree3$1(TypeComparer.scala:100)
        at dotty.tools.dotc.core.TypeComparer.$anonfun$isSubType$3(TypeComparer.scala:97)
        at dotty.tools.dotc.core.TypeComparer$$Lambda$435/2009787198.apply$mcZ$sp(Unknown Source)
        at scala.compat.java8.JFunction0$mcZ$sp.apply(JFunction0$mcZ$sp.java:12)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:148)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.core.TypeComparer.isSubType(TypeComparer.scala:91)
        at dotty.tools.dotc.core.TypeComparer.topLevelSubType(TypeComparer.scala:85)
        at dotty.tools.dotc.core.Types$Type.$anonfun$$less$colon$less$1(Types.scala:595)
        at dotty.tools.dotc.core.Types$Type$$Lambda$433/1047503754.apply$mcZ$sp(Unknown Source)
        at scala.compat.java8.JFunction0$mcZ$sp.apply(JFunction0$mcZ$sp.java:12)
        at dotty.tools.dotc.util.Stats$.track(Stats.scala:31)
        at dotty.tools.dotc.core.Types$Type.$less$colon$less(Types.scala:594)
        at dotty.tools.dotc.typer.ProtoTypes$Compatibility.isCompatible(ProtoTypes.scala:37)
        at dotty.tools.dotc.typer.Typer.isCompatible(Typer.scala:57)
        at dotty.tools.dotc.typer.ProtoTypes$Compatibility.constrainResult(ProtoTypes.scala:61)
        at dotty.tools.dotc.typer.Typer.constrainResult(Typer.scala:57)
        at dotty.tools.dotc.typer.Applications$Application.init(Applications.scala:183)
        at dotty.tools.dotc.typer.Applications$TypedApply.<init>(Applications.scala:434)
        at dotty.tools.dotc.typer.Applications$ApplyToUntyped.<init>(Applications.scala:512)
        at dotty.tools.dotc.typer.Applications.$anonfun$$anonfun$realApply$1$2(Applications.scala:549)
        at dotty.tools.dotc.typer.Applications$$Lambda$496/1938056729.apply(Unknown Source)
        at dotty.tools.dotc.typer.Typer.tryEither(Typer.scala:1215)
        at dotty.tools.dotc.typer.Applications.$anonfun$realApply$1(Applications.scala:559)
        at dotty.tools.dotc.typer.Applications$$Lambda$494/1459794865.apply(Unknown Source)
        at dotty.tools.dotc.util.Stats$.track(Stats.scala:31)
        at dotty.tools.dotc.typer.Applications.realApply$1(Applications.scala:530)
        at dotty.tools.dotc.typer.Applications.typedApply(Applications.scala:596)
        at dotty.tools.dotc.typer.Typer.typedApply(Typer.scala:57)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:1120)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1160)
        at dotty.tools.dotc.typer.ProtoTypes$FunProto.typedArg(ProtoTypes.scala:201)
        at dotty.tools.dotc.typer.Applications$ApplyToUntyped.typedArg(Applications.scala:513)
        at dotty.tools.dotc.typer.Applications$ApplyToUntyped.typedArg(Applications.scala:511)
        at dotty.tools.dotc.typer.Applications$Application.addTyped$1(Applications.scala:316)
        at dotty.tools.dotc.typer.Applications$Application.matchArgs(Applications.scala:355)
        at dotty.tools.dotc.typer.Applications$Application.matchArgs(Applications.scala:356)
        at dotty.tools.dotc.typer.Applications$Application.init(Applications.scala:192)
        at dotty.tools.dotc.typer.Applications$TypedApply.<init>(Applications.scala:434)
        at dotty.tools.dotc.typer.Applications$ApplyToUntyped.<init>(Applications.scala:512)
        at dotty.tools.dotc.typer.Applications.$anonfun$$anonfun$realApply$1$2(Applications.scala:549)
        at dotty.tools.dotc.typer.Applications$$Lambda$496/1938056729.apply(Unknown Source)
        at dotty.tools.dotc.typer.Typer.tryEither(Typer.scala:1215)
        at dotty.tools.dotc.typer.Applications.$anonfun$realApply$1(Applications.scala:559)
        at dotty.tools.dotc.typer.Applications$$Lambda$494/1459794865.apply(Unknown Source)
        at dotty.tools.dotc.util.Stats$.track(Stats.scala:31)
        at dotty.tools.dotc.typer.Applications.realApply$1(Applications.scala:530)
        at dotty.tools.dotc.typer.Applications.typedApply(Applications.scala:596)
        at dotty.tools.dotc.typer.Typer.typedApply(Typer.scala:57)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:1120)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1160)
        at dotty.tools.dotc.typer.Typer.liftedTree12$1(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer.$anonfun$typed$2(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer$$Lambda$334/940553268.apply(Unknown Source)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:167)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:149)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1168)
        at dotty.tools.dotc.typer.Typer.$anonfun$typedIf$1(Typer.scala:494)
        at dotty.tools.dotc.typer.Typer$$Lambda$549/143110009.apply(Unknown Source)
        at dotty.tools.dotc.util.Stats$.track(Stats.scala:31)
        at dotty.tools.dotc.typer.Typer.typedIf(Typer.scala:492)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:1129)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1160)
        at dotty.tools.dotc.typer.Typer.liftedTree12$1(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer.$anonfun$typed$2(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer$$Lambda$334/940553268.apply(Unknown Source)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:167)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:149)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1168)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:1207)
        at dotty.tools.dotc.typer.Typer.$anonfun$typedBlock$2(Typer.scala:447)
        at dotty.tools.dotc.typer.Typer$$Lambda$544/1663411182.apply(Unknown Source)
        at dotty.tools.dotc.util.Stats$.track(Stats.scala:31)
        at dotty.tools.dotc.typer.Typer.typedBlock(Typer.scala:444)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:1128)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1160)
        at dotty.tools.dotc.typer.Typer.liftedTree12$1(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer.$anonfun$typed$2(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer$$Lambda$334/940553268.apply(Unknown Source)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:167)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:149)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1168)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:1207)
        at dotty.tools.dotc.typer.Typer.caseRest$1(Typer.scala:678)
        at dotty.tools.dotc.typer.Typer.$anonfun$typedCase$3(Typer.scala:693)
        at dotty.tools.dotc.typer.Typer$$Lambda$728/439928219.apply(Unknown Source)
        at dotty.tools.dotc.util.Stats$.track(Stats.scala:31)
        at dotty.tools.dotc.typer.Typer.typedCase(Typer.scala:667)
        at dotty.tools.dotc.typer.Typer.$anonfun$typedCases$1(Typer.scala:661)
        at dotty.tools.dotc.typer.Typer$$Lambda$727/1150284200.apply(Unknown Source)
        at dotty.tools.dotc.core.Decorators$ListDecorator$.loop$4(Decorators.scala:51)
        at dotty.tools.dotc.core.Decorators$ListDecorator$.mapconserve$extension(Decorators.scala:67)
        at dotty.tools.dotc.typer.Typer.typedCases(Typer.scala:661)
        at dotty.tools.dotc.typer.Typer.$anonfun$typedMatch$1(Typer.scala:633)
        at dotty.tools.dotc.typer.Typer$$Lambda$724/436546048.apply(Unknown Source)
        at dotty.tools.dotc.util.Stats$.track(Stats.scala:31)
        at dotty.tools.dotc.typer.Typer.typedMatch(Typer.scala:624)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:1132)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1160)
        at dotty.tools.dotc.typer.Typer.liftedTree12$1(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer.$anonfun$typed$2(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer$$Lambda$334/940553268.apply(Unknown Source)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:167)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:149)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1168)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:1207)
        at dotty.tools.dotc.typer.Typer.$anonfun$typedDefDef$2(Typer.scala:934)
        at dotty.tools.dotc.typer.Typer$$Lambda$504/1690254271.apply(Unknown Source)
        at dotty.tools.dotc.util.Stats$.track(Stats.scala:31)
        at dotty.tools.dotc.typer.Typer.typedDefDef(Typer.scala:927)
        at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:1108)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1158)
        at dotty.tools.dotc.typer.Typer.liftedTree12$1(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer.$anonfun$typed$2(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer$$Lambda$334/940553268.apply(Unknown Source)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:167)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:149)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1168)
        at dotty.tools.dotc.typer.Typer.traverse$2(Typer.scala:1192)
        at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:1203)
        at dotty.tools.dotc.typer.Typer.$anonfun$typedClassDef$3(Typer.scala:963)
        at dotty.tools.dotc.typer.Typer$$Lambda$500/1234776885.apply(Unknown Source)
        at dotty.tools.dotc.util.Stats$.track(Stats.scala:31)
        at dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:946)
        at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:1111)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1158)
        at dotty.tools.dotc.typer.Typer.liftedTree12$1(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer.$anonfun$typed$2(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer$$Lambda$334/940553268.apply(Unknown Source)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:167)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:149)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1168)
        at dotty.tools.dotc.typer.Typer.traverse$2(Typer.scala:1192)
        at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:1203)
        at dotty.tools.dotc.typer.Typer.$anonfun$typedClassDef$3(Typer.scala:963)
        at dotty.tools.dotc.typer.Typer$$Lambda$500/1234776885.apply(Unknown Source)
        at dotty.tools.dotc.util.Stats$.track(Stats.scala:31)
        at dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:946)
        at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:1111)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1158)
        at dotty.tools.dotc.typer.Typer.liftedTree12$1(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer.$anonfun$typed$2(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer$$Lambda$334/940553268.apply(Unknown Source)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:167)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:149)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1168)
        at dotty.tools.dotc.typer.Typer.traverse$2(Typer.scala:1192)
        at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:1203)
        at dotty.tools.dotc.typer.Typer.$anonfun$typedPackageDef$1(Typer.scala:1051)
        at dotty.tools.dotc.typer.Typer$$Lambda$340/234698513.apply(Unknown Source)
        at dotty.tools.dotc.util.Stats$.track(Stats.scala:31)
        at dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:1042)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:1148)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1160)
        at dotty.tools.dotc.typer.Typer.liftedTree12$1(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer.$anonfun$typed$2(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer$$Lambda$334/940553268.apply(Unknown Source)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:167)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:149)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1168)
        at dotty.tools.dotc.typer.Typer.traverse$2(Typer.scala:1198)
        at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:1203)
        at dotty.tools.dotc.typer.Typer.$anonfun$typedPackageDef$1(Typer.scala:1051)
        at dotty.tools.dotc.typer.Typer$$Lambda$340/234698513.apply(Unknown Source)
        at dotty.tools.dotc.util.Stats$.track(Stats.scala:31)
        at dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:1042)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:1148)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1160)
        at dotty.tools.dotc.typer.Typer.liftedTree12$1(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer.$anonfun$typed$2(Typer.scala:1170)
        at dotty.tools.dotc.typer.Typer$$Lambda$334/940553268.apply(Unknown Source)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:167)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.reporting.Reporting.traceIndented(Reporter.scala:149)
        at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:53)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1168)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:1207)
        at dotty.tools.dotc.typer.FrontEnd.$anonfun$typeCheck$1(FrontEnd.scala:42)
        at dotty.tools.dotc.typer.FrontEnd$$Lambda$332/1032616650.apply$mcV$sp(Unknown Source)
        at scala.compat.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
        at dotty.tools.dotc.typer.FrontEnd.monitor(FrontEnd.scala:19)
        at dotty.tools.dotc.typer.FrontEnd.typeCheck(FrontEnd.scala:46)
        at dotty.tools.dotc.typer.FrontEnd.$anonfun$runOn$4(FrontEnd.scala:53)
        at dotty.tools.dotc.typer.FrontEnd$$Lambda$331/440434003.applyVoid(Unknown Source)
        at scala.compat.java8.JProcedure1.apply(JProcedure1.java:18)
        at scala.compat.java8.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.immutable.List.foreach(List.scala:381)
        at dotty.tools.dotc.typer.FrontEnd.runOn(FrontEnd.scala:53)
        at dotty.tools.dotc.Run.$anonfun$$anonfun$5(Run.scala:59)
        at dotty.tools.dotc.Run$$Lambda$194/611437735.applyVoid(Unknown Source)
        at scala.compat.java8.JProcedure1.apply(JProcedure1.java:18)
        at scala.compat.java8.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33)
        at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:186)
        at dotty.tools.dotc.Run.$anonfun$compileUnits$1(Run.scala:57)
        at dotty.tools.dotc.Run$$Lambda$185/1761291320.apply$mcV$sp(Unknown Source)
        at scala.compat.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
        at dotty.tools.dotc.util.Stats$.monitorHeartBeat(Stats.scala:58)
        at dotty.tools.dotc.Run.compileUnits(Run.scala:65)
        at dotty.tools.dotc.Run.compileSources(Run.scala:49)
        at dotty.tools.dotc.Run.compile(Run.scala:33)
        at dotty.tools.dotc.Driver.doCompile(Driver.scala:21)
        at dotty.tools.dotc.Driver.process(Driver.scala:44)
        at dotty.tools.dotc.Driver.main(Driver.scala:48)
        at dotty.tools.dotc.Main.main(Main.scala)