diff options
| -rw-r--r-- | src/compiler/scala/tools/nsc/matching/ParallelMatching.scala | 21 | ||||
| -rw-r--r-- | test/files/run/castsingleton.check | 2 | ||||
| -rw-r--r-- | test/files/run/castsingleton.scala | 11 |
3 files changed, 28 insertions, 6 deletions
diff --git a/src/compiler/scala/tools/nsc/matching/ParallelMatching.scala b/src/compiler/scala/tools/nsc/matching/ParallelMatching.scala index c5fd840973..ba7eac7ea0 100644 --- a/src/compiler/scala/tools/nsc/matching/ParallelMatching.scala +++ b/src/compiler/scala/tools/nsc/matching/ParallelMatching.scala @@ -560,7 +560,7 @@ trait ParallelMatching extends ast.TreeDSL j -> (moreSpecific :: subsumed) lazy val casted = scrut castedTo pmatch.headType - lazy val cond = condition(checkErroneous(casted), scrut) + lazy val cond = condition(checkErroneous(casted), scrut, head.boundVariables.nonEmpty) private def isAnyMoreSpecific = yeses exists (x => !x.moreSpecific.isEmpty) lazy val (subtests, subtestVars) = @@ -803,17 +803,17 @@ trait ParallelMatching extends ast.TreeDSL /** returns the condition in "if (cond) k1 else k2" */ - final def condition(tpe: Type, scrut: Scrutinee): Tree = { + final def condition(tpe: Type, scrut: Scrutinee, isBound: Boolean): Tree = { assert(scrut.isDefined) - val cond = handleOuter(condition(tpe, scrut.id)) + val cond = handleOuter(condition(tpe, scrut.id, isBound)) if (!needsOuterTest(tpe, scrut.tpe, owner)) cond else addOuterCondition(cond, tpe, scrut.id) } - final def condition(tpe: Type, scrutTree: Tree): Tree = { + final def condition(tpe: Type, scrutTree: Tree, isBound: Boolean): Tree = { assert((tpe ne NoType) && (scrutTree.tpe ne NoType)) - def useEqTest = tpe.termSymbol.isModule || (tpe.prefix eq NoPrefix) + def useEqTest = tpe.termSymbol.isModule || (tpe.prefix eq NoPrefix) // case SingleType(_, _) | ThisType(_) | SuperType(_, _) => // val cmpOp = if (targ.tpe <:< AnyValClass.tpe) Any_equals else Object_eq @@ -824,7 +824,16 @@ trait ParallelMatching extends ast.TreeDSL case v @ Constant(null) if scrutTree.tpe.isAnyRef => scrutTree ANY_EQ NULL case v => scrutTree MEMBER_== Literal(v) } - case _: SingletonType if useEqTest => REF(tpe.termSymbol) MEMBER_== scrutTree + case _: SingletonType if useEqTest => + val eqTest = REF(tpe.termSymbol) MEMBER_== scrutTree + // See ticket #1503 for the motivation behind checking for a binding. + // The upshot is that it is unsound to assume equality means the right + // type, but if the value doesn't appear on the right hand side of the + // match that's unimportant; so we add an instance check only if there + // is a binding. + if (isBound) eqTest AND (scrutTree IS tpe.widen) + else eqTest + case _ if scrutTree.tpe <:< tpe && tpe.isAnyRef => scrutTree OBJ_!= NULL case _ => scrutTree IS tpe }) diff --git a/test/files/run/castsingleton.check b/test/files/run/castsingleton.check new file mode 100644 index 0000000000..49742281f0 --- /dev/null +++ b/test/files/run/castsingleton.check @@ -0,0 +1,2 @@ +L() +L() diff --git a/test/files/run/castsingleton.scala b/test/files/run/castsingleton.scala new file mode 100644 index 0000000000..f907467741 --- /dev/null +++ b/test/files/run/castsingleton.scala @@ -0,0 +1,11 @@ +object Test extends Application { + case class L(); + object N extends L(); + + def empty(xs : L) : Unit = xs match { + case x@N => println(x); println(x); + case x => println(x); println(x); + } + + empty(L()) +} |