diff options
| -rw-r--r-- | test/dotc/tests.scala | 1 | ||||
| -rw-r--r-- | tests/neg/Iter2.scala | 40 |
2 files changed, 41 insertions, 0 deletions
diff --git a/test/dotc/tests.scala b/test/dotc/tests.scala index 3787a9c98..895bf89a7 100644 --- a/test/dotc/tests.scala +++ b/test/dotc/tests.scala @@ -148,6 +148,7 @@ class tests extends CompilerTest { @Test def neg_boundspropagation = compileFile(negDir, "boundspropagation", xerrors = 5) @Test def neg_refinedSubtyping = compileFile(negDir, "refinedSubtyping", xerrors = 2) @Test def neg_hklower = compileFile(negDir, "hklower", xerrors = 3) + @Test def neg_Iter2 = compileFile(negDir, "Iter2", xerrors = 2) @Test def neg_i0091_infpaths = compileFile(negDir, "i0091-infpaths", xerrors = 3) @Test def neg_i0248_inherit_refined = compileFile(negDir, "i0248-inherit-refined", xerrors = 4) @Test def neg_i0281 = compileFile(negDir, "i0281-null-primitive-conforms", xerrors = 3) diff --git a/tests/neg/Iter2.scala b/tests/neg/Iter2.scala new file mode 100644 index 000000000..d938f0379 --- /dev/null +++ b/tests/neg/Iter2.scala @@ -0,0 +1,40 @@ +// NOTE: this test case is very fragile, removing seemingly unrelated code like +// the "Dummy" trait somehow changes how the types of cget and dget are inferred +// and avoids the bug. + +object Test { + trait Dummy { + def foo: Unit = { + var i = 0 + i += 1 + } + } + + trait FromIterator[+C[X] <: Iterable[X]] { + def get(): C[Int] + } + + trait Iterable[+IA] extends FromIterator[Iterable] + trait SubIterable[+IA] extends Iterable[IA] with FromIterator[SubIterable] + + class IterableC extends Iterable[Int] { def get() = this } + class SubIterableC extends SubIterable[Int] { def get() = this } + + + implicit class IterableTransforms[A, C[X] <: Iterable[X], D[X] <: SubIterable[X]] + (val dummy: Unit) { + def foo(c: Iterable[A] with FromIterator[C], d: Iterable[A] with FromIterator[D]): Unit = { + var cget = c.get() + var dget = d.get() + dget = cget // error + cget = dget // error + } + } + + def main(args: Array[String]): Unit = { + new IterableTransforms(()).foo(new IterableC, new SubIterableC) + // java.lang.ClassCastException: Test$IterableC cannot be cast to Test$SubIterable + } +} + + |