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author | Jason Zaugg <jzaugg@gmail.com> | 2014-02-13 21:49:18 +0100 |
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committer | Jason Zaugg <jzaugg@gmail.com> | 2014-02-13 21:58:13 +0100 |
commit | 922d090f5c2dd8a14f2bb7915a04c5156d29ea1b (patch) | |
tree | 82accbfbf13c9c492d0a43bb47c562d77c30275b /test | |
parent | c83e01d47d941265fa5415c0f29a884c904fdfa0 (diff) | |
download | scala-922d090f5c2dd8a14f2bb7915a04c5156d29ea1b.tar.gz scala-922d090f5c2dd8a14f2bb7915a04c5156d29ea1b.tar.bz2 scala-922d090f5c2dd8a14f2bb7915a04c5156d29ea1b.zip |
SI-8276 Test for cyclic error caused by (reverted) SI-1786 fix
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 2dbd17a2 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
Diffstat (limited to 'test')
-rw-r--r-- | test/files/pos/t1786-cycle.scala | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/test/files/pos/t1786-cycle.scala b/test/files/pos/t1786-cycle.scala new file mode 100644 index 0000000000..af5d892c6a --- /dev/null +++ b/test/files/pos/t1786-cycle.scala @@ -0,0 +1,57 @@ +trait GenTraversableLike[+A, +Repr] extends Any + +object O { + (null: Any) match { + case _: LongTraversableLike[_] => + } +} + +trait LongTraversable extends LongTraversableLike[LongTraversable] + +trait LongTraversableLike[+Repr <: LongTraversableLike[Repr]] extends GenTraversableLike[Any, Repr] + +/* +% scalac-hash v2.11.0-M8 test/files/pos/t1786-cycle.scala +[warn] v2.11.0-M8 failed, using closest available +test/files/pos/t1786-cycle.scala:11: error: illegal cyclic reference involving trait LongTraversableLike +trait LongTraversableLike[+Repr <: LongTraversableLike[Repr]] extends GenTraversableLike[Any, Repr] + ^ +one error found + +Okay again after SI-1786 was reverted. + + +|-- object O BYVALmode-EXPRmode (site: package <empty>) +| |-- super EXPRmode-POLYmode-QUALmode (silent: <init> in O) +| | |-- this EXPRmode (silent: <init> in O) +| | | \-> O.type +| | \-> O.type +| |-- (null: Any) match { case (_: LongTraversableLike[(_ @ <em... BYVALmode-EXPRmode (site: value <local O> in O) +| | |-- (null: Any) BYVALmode-EXPRmode (site: value <local O> in O) +| | | |-- Any TYPEmode (site: value <local O> in O) +| | | | \-> Any +| | | |-- null : pt=Any EXPRmode (site: value <local O> in O) +| | | | \-> Null(null) +| | | \-> Any +| | |-- (_: LongTraversableLike[(_ @ <empty>)]) : pt=Any PATTERNmode (site: value <local O> in O) enrichment only +| | | |-- LongTraversableLike[(_ @ <empty>)] TYPEPATmode-TYPEmode (site: value <local O> in O) enrichment only +| | | | |-- <: LongTraversableLike[Repr] TYPEmode (site: type Repr in <empty>) +| | | | | |-- LongTraversableLike[Repr] TYPEmode (site: type Repr in <empty>) +| | | | | | |-- Repr NOmode (site: type Repr in <empty>) +| | | | | | | \-> Repr +| | | | | | \-> LongTraversableLike[Repr] +| | | | | [adapt] <: LongTraversableLike[Repr] is now a TypeTree( <: LongTraversableLike[Repr]) +| | | | | \-> <: LongTraversableLike[Repr] +| | | | |-- (_ @ <empty>) TYPEPATmode-TYPEmode (site: value <local O> in O) enrichment only +| | | | | \-> _ +| | | | |-- GenTraversableLike FUNmode-TYPEmode (site: trait LongTraversableLike) +| | | | | \-> GenTraversableLike +| | | | |-- GenTraversableLike[Any, Repr] TYPEmode (site: trait LongTraversableLike) +| | | | | |-- Any TYPEmode (site: trait LongTraversableLike) +| | | | | | \-> Any +| | | | | |-- Repr TYPEmode (site: trait LongTraversableLike) +| | | | | | \-> Repr +| | | | | caught scala.reflect.internal.Symbols$CyclicReference: illegal cyclic reference involving trait LongTraversableLike: while typing GenTraversableLike[Any, Repr] +test/files/pos/t1786-cycle.scala:11: error: illegal cyclic reference involving trait LongTraversableLike +trait LongTraversableLike[+Repr <: LongTraversableLike[Repr]] extends GenT +*/
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