SI-8276 Test for cyclic error caused by (reverted) SI-1786 fix #3526
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We reverted SI-1786 recently on the grounds that its means of avoiding cycles (not sharpening bounds of T[_] when T is uninitialized) caused unacceptable non-determinism (well: compilation order dependency) to type inference. Nary a day later, @gkossakowski hit a regression in scala-io. Bisection revealed that it stopped working in 2dbd17a and started working agiain after the revert. How's that for prescience! I've distilled the cyclic error in scala-io in this test case. I'm yet to pinpoint this, followon error, which didn't survive the shrink ray, and only appeared in the original code: error: java.lang.IndexOutOfBoundsException: 0 at scala.collection.LinearSeqOptimized$class.apply(LinearSeqOptimized.scala:51) at scala.collection.immutable.List.apply(List.scala:83) at scala.reflect.internal.tpe.TypeMaps$AsSeenFromMap.correspondingTypeArgument(TypeMaps.scala:5
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LGTM! |
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LGTM Thanks! |
gkossakowski
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Feb 14, 2014
SI-8276 Test for cyclic error caused by (reverted) SI-1786 fix
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We reverted SI-1786 recently on the grounds that its means of
avoiding cycles (not sharpening bounds of T[_] when T is
uninitialized) caused unacceptable non-determinism (well:
compilation order dependency) to type inference.
Nary a day later, @gkossakowski hit a regression in scala-io.
Bisection revealed that it stopped working in 2dbd17a and
started working agiain after the revert. How's that for
prescience!
I've distilled the cyclic error in scala-io in this test
case.
I'm yet to pinpoint this, followon error, which didn't survive
the shrink ray, and only appeared in the original code:
Review by @gkossakowski.
/cc @adriaanm (it will make a good test case for the alternative
approach you're trying.)