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Compiler loops infinitely[on multiple cores] when anon Iterator object tries to store 'this' #8865

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scabug opened this issue Sep 27, 2014 · 2 comments
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Compiler loops infinitely[on multiple cores] when anon Iterator object tries to store 'this' #8865

scabug opened this issue Sep 27, 2014 · 2 comments
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duplicate
Milestone
2.11.0-RC1

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@scabug
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scabug commented Sep 27, 2014 •
edited by retronym

Attempting to compile the following code will cause scalac to spin fruitlessly on multiple cores until the JVM runs out of memory

class Point{
  def iter =
    new Iterator[Point]{
      var currentPosition = this
      def next:Point = currentPosition
      def hasNext:Boolean = true
    }
}

This appears to be due to the var currentPosition = this [when I introduced the bug into the code base I guess I was thinking 'this' would refer to the Point, it does not, of course. The compiler should complain at def next...]
@scabug
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scabug commented Sep 27, 2014

Imported From: https://issues.scala-lang.org/browse/SI-8865?orig=1
Reporter: mako yass (makoConstruct)
Affected Versions: 2.9.2, 2.10.2
Duplicates #8158

@scabug
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scabug commented Sep 27, 2014

@gourlaysama said:
That's a duplicate of #8158 (although that ticket's title seem to imply it is about macros, it is more general than that, see comments): the compiler hangs while trying to print the error message in that code.

In 2.11.2, this prints:

test.scala:5: error: type mismatch;
 found   : Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[Point]{def currentPosition: $anon; def currentPosition_=(x$1: Iterator[...]{def currentPosition: $anon; def currentPosition_=(x$1: ...{def currentPosition: $anon; def currentPosition_=(x$1: ...): ...}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}): Unit}
 required: Point
      def next:Point = currentPosition
                       ^
one error found

It was fixed in v2.11.0-RC1 (in 936d60a).

@scabug scabug closed this as completed Sep 27, 2014
@scabug scabug added this to the 2.11.0-RC1 milestone Apr 7, 2017
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