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author | Jason Zaugg <jzaugg@gmail.com> | 2014-02-12 14:41:36 +0100 |
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committer | Adriaan Moors <adriaan.moors@typesafe.com> | 2014-02-12 20:54:47 -0800 |
commit | c956a27c3278b99d45676c268955a9e58a1ed15c (patch) | |
tree | 0c30690c97b32232398f0ae36fa059ccc835d84d /test/pending | |
parent | b4e1a308f81d48b72ba90b7a8594759f27e1d8f3 (diff) | |
download | scala-c956a27c3278b99d45676c268955a9e58a1ed15c.tar.gz scala-c956a27c3278b99d45676c268955a9e58a1ed15c.tar.bz2 scala-c956a27c3278b99d45676c268955a9e58a1ed15c.zip |
SI-5900 Fix pattern inference regression
This commit does not close SI-5900. It only addresses a regression
in 2.11 prereleases caused by SI-7886.
The fix for SI-7886 was incomplete (as shown by the last commit)
and incorrect (as shown by the regression in pos/t5900a.scala and
the fact it ended up inferring type parameters.)
I believe that the key to fixing this problem will be unifying
the inference of case class constructor patterns and extractor
patterns.
I've explored that idea:
https://gist.github.com/retronym/7704153
https://github.com/retronym/scala/compare/ticket/5900
But didn't quite get there.
Diffstat (limited to 'test/pending')
-rw-r--r-- | test/pending/neg/t7886.scala | 22 | ||||
-rw-r--r-- | test/pending/pos/pattern-typing.scala | 29 |
2 files changed, 51 insertions, 0 deletions
diff --git a/test/pending/neg/t7886.scala b/test/pending/neg/t7886.scala new file mode 100644 index 0000000000..55d80a0a43 --- /dev/null +++ b/test/pending/neg/t7886.scala @@ -0,0 +1,22 @@ +trait Covariant[+A] +trait Contra[-A] { def accept(p: A): Unit } +trait Invariant[A] extends Covariant[A] with Contra[A] + +case class Unravel[A](m: Contra[A], msg: A) + +object Test extends Covariant[Any] { + def g(m: Contra[Any]): Unit = m accept 5 + def f(x: Any): Unit = x match { + case Unravel(m, msg) => g(m) + case _ => + } + def main(args: Array[String]) { + f(Unravel[String](new Contra[String] { def accept(x: String) = x.length }, "")) + } +} +// java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String +// at Test$$anon$1.accept(a.scala:18) +// at Test$.g(a.scala:13) +// at Test$.f(a.scala:15) +// at Test$.main(a.scala:18) +// at Test.main(a.scala) diff --git a/test/pending/pos/pattern-typing.scala b/test/pending/pos/pattern-typing.scala new file mode 100644 index 0000000000..7286cc38af --- /dev/null +++ b/test/pending/pos/pattern-typing.scala @@ -0,0 +1,29 @@ +import scala.language.higherKinds + +trait Bound[B] + +package p1 { + case class Sub[B <: Bound[B]](p: B) + object Test { + def g[A](x: Bound[A]) = () + def f(x: Any) = x match { case Sub(p) => g(p) } + } +} + +package p2 { + trait Traversable[+A] { def head: A = ??? } + trait Seq[+A] extends Traversable[A] { def length: Int = ??? } + + case class SubHK[B <: Bound[B], CC[X] <: Traversable[X]](xs: CC[B]) + class MyBound extends Bound[MyBound] + class MySeq extends Seq[MyBound] + + object Test { + def g[B](x: Bound[B]) = () + + def f1(x: Any) = x match { case SubHK(xs) => xs } + def f2[B <: Bound[B], CC[X] <: Traversable[X]](sub: SubHK[B, CC]): CC[B] = sub match { case SubHK(xs) => xs } + def f3 = g(f1(SubHK(new MySeq)).head) + def f4 = g(f2(SubHK(new MySeq)).head) + } +} |