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OlivierBlanvillain opened this issue Nov 8, 2016 · 3 comments
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Exponential compilation time of "1" + 1 + "1" + ... #1687

OlivierBlanvillain opened this issue Nov 8, 2016 · 3 comments
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@DarkDimius
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area:transform exp:expert itype:enhancement

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@OlivierBlanvillain
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The following complies in 11s:

object O {
  def f: String = {
    "1" + 1 + "1" + 1 +
    "1" + 1 + "1" + 1 +
    "1" + 1 + "1" + 1 +
    "1" + 1 + "1" + 1 +
    "1" + 1 + "1" + 1 +
    "1" + 1 + "1" + 1
  }
}
@OlivierBlanvillain OlivierBlanvillain mentioned this issue Nov 9, 2016
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@DarkDimius
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@OlivierBlanvillain in which phase is it spending time? is it tailrec?

@OlivierBlanvillain
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Yes it's spending time in tailrec doing lots of isSubType calls

@DarkDimius DarkDimius self-assigned this Nov 9, 2016
@DarkDimius
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Thanks for minimizing. I'll have a look at this after PLDI deadline.

OlivierBlanvillain added a commit to OlivierBlanvillain/scalatest that referenced this issue Nov 9, 2016
@OlivierBlanvillain
Temporary workaround for scalatest#1687
d3ddec4 
scala/scala3#1687
OlivierBlanvillain added a commit to OlivierBlanvillain/scalatest that referenced this issue Nov 10, 2016
@OlivierBlanvillain
Temporary workaround for scalatest#1687
ab14ff3 
scala/scala3#1687
DarkDimius added a commit to dotty-staging/dotty that referenced this issue Jan 22, 2017
@DarkDimius
Test that scala#1687 is fixed.
945001d 
The b-test would compile for a millenia without the fix.
DarkDimius added a commit that referenced this issue Jan 28, 2017
@DarkDimius
Merge pull request #1909 from dotty-staging/fix-1687
d5201d3 
Fix #1687: postpone computations in tailrec until they are needed.
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@liufengyun @DarkDimius @OlivierBlanvillain