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author | Jason Zaugg <jzaugg@gmail.com> | 2014-05-23 12:26:43 +0200 |
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committer | Jason Zaugg <jzaugg@gmail.com> | 2014-06-10 17:30:28 +0200 |
commit | 7046d73e2a1d88273a8382f27a4fb0af6f87db3b (patch) | |
tree | 14a2ea05fde37f519323647336f9f380b9beb70a /test/files/run/t8611c.scala | |
parent | ddb29a8105bc3b692bc129cbd8ed111baae7076d (diff) | |
download | scala-7046d73e2a1d88273a8382f27a4fb0af6f87db3b.tar.gz scala-7046d73e2a1d88273a8382f27a4fb0af6f87db3b.tar.bz2 scala-7046d73e2a1d88273a8382f27a4fb0af6f87db3b.zip |
SI-8611 Avoid accidental patmat unification with refinement types
In the enclosed test, t8611a.scala, the patterns `O.{A, B}` were
incorrect treated as equivelent by the combination of
`uniqueTpForTree` and `Const.uniqueTpForTree`.
`uniqueTpForTree` used `Type#narrow` to try to create a distinct
type for each new pattern tree it encountered. However, narrowing a
`RefinedType` does not create a distinct type as we are used to
when narrowing, e.g. a class type.
// Type
def narrow: Type =
if (phase.erasedTypes) this
else {
val cowner = commonOwner(this)
refinedType(this :: Nil, cowner, EmptyScope, cowner.pos).narrow
}
// CompoundType
override def narrow: Type = typeSymbol.thisType
This commit creates a fresh existential type symbol rather than
trying to use `narrow`.
I've included a unit test to show the sublteties of narrowing
refinment types.
Diffstat (limited to 'test/files/run/t8611c.scala')
-rw-r--r-- | test/files/run/t8611c.scala | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/test/files/run/t8611c.scala b/test/files/run/t8611c.scala new file mode 100644 index 0000000000..2bd17f29a5 --- /dev/null +++ b/test/files/run/t8611c.scala @@ -0,0 +1,21 @@ +trait K +trait L + +object O { + type LK = K with L +} + +object Test extends App { + local + + def local = { + val A: O.LK = new K with L + val B: O.LK = new K with L + val scrut: O.LK = A + scrut match { + case B if "".isEmpty => ??? + case A => + case B => ??? + } + } +} |