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author | Jason Zaugg <jzaugg@gmail.com> | 2014-06-11 09:25:50 +0200 |
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committer | Jason Zaugg <jzaugg@gmail.com> | 2014-06-11 09:25:50 +0200 |
commit | b664a488acca9d89c600f5b87ba9a9ca77aace59 (patch) | |
tree | a912905d3d00c7488ab11524918c715742e77765 | |
parent | a7046785e98db823a25eaaa975e571baed89690a (diff) | |
parent | 78caf290f86b965cc0d750d55a62ebea567d613d (diff) | |
download | scala-b664a488acca9d89c600f5b87ba9a9ca77aace59.tar.gz scala-b664a488acca9d89c600f5b87ba9a9ca77aace59.tar.bz2 scala-b664a488acca9d89c600f5b87ba9a9ca77aace59.zip |
Merge pull request #3797 from retronym/topic/exhaust-compound
SI-8631 Treat `A with Sealed` as enumerable for pattern matching
4 files changed, 59 insertions, 4 deletions
diff --git a/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala b/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala index 894f959319..e1a663ea41 100644 --- a/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala +++ b/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala @@ -104,11 +104,18 @@ trait TreeAndTypeAnalysis extends Debugging { // TODO case _ if tp.isTupleType => // recurse into component types case modSym: ModuleClassSymbol => Some(List(tp)) + case sym: RefinementClassSymbol => + val parentSubtypes: List[Option[List[Type]]] = tp.parents.map(parent => enumerateSubtypes(parent)) + if (parentSubtypes exists (_.isDefined)) + // If any of the parents is enumerable, then the refinement type is enumerable. + Some( + // We must only include subtypes of the parents that conform to `tp`. + // See neg/virtpatmat_exhaust_compound.scala for an example. + parentSubtypes flatMap (_.getOrElse(Nil)) filter (_ <:< tp) + ) + else None // make sure it's not a primitive, else (5: Byte) match { case 5 => ... } sees no Byte - case sym if !sym.isSealed || isPrimitiveValueClass(sym) => - debug.patmat("enum unsealed "+ ((tp, sym, sym.isSealed, isPrimitiveValueClass(sym)))) - None - case sym => + case sym if sym.isSealed => val subclasses = debug.patmatResult(s"enum $sym sealed, subclasses")( // symbols which are both sealed and abstract need not be covered themselves, because // all of their children must be and they cannot otherwise be created. @@ -136,6 +143,9 @@ trait TreeAndTypeAnalysis extends Debugging { else None } }) + case sym => + debug.patmat("enum unsealed "+ ((tp, sym, sym.isSealed, isPrimitiveValueClass(sym)))) + None } // approximate a type to the static type that is fully checkable at run time, diff --git a/test/files/neg/virtpatmat_exhaust_compound.check b/test/files/neg/virtpatmat_exhaust_compound.check new file mode 100644 index 0000000000..72e0340682 --- /dev/null +++ b/test/files/neg/virtpatmat_exhaust_compound.check @@ -0,0 +1,15 @@ +virtpatmat_exhaust_compound.scala:14: warning: match may not be exhaustive. +It would fail on the following inputs: O1, O2, O4 + a match { + ^ +virtpatmat_exhaust_compound.scala:18: warning: match may not be exhaustive. +It would fail on the following input: O4 + def t1(a: Product with Base with Base2) = a match { + ^ +virtpatmat_exhaust_compound.scala:22: warning: match may not be exhaustive. +It would fail on the following input: O2 + def t2(a: Product with Base { def foo: Int }) = a match { + ^ +error: No warnings can be incurred under -Xfatal-warnings. +three warnings found +one error found diff --git a/test/files/neg/virtpatmat_exhaust_compound.flags b/test/files/neg/virtpatmat_exhaust_compound.flags new file mode 100644 index 0000000000..85d8eb2ba2 --- /dev/null +++ b/test/files/neg/virtpatmat_exhaust_compound.flags @@ -0,0 +1 @@ +-Xfatal-warnings diff --git a/test/files/neg/virtpatmat_exhaust_compound.scala b/test/files/neg/virtpatmat_exhaust_compound.scala new file mode 100644 index 0000000000..386c7af98d --- /dev/null +++ b/test/files/neg/virtpatmat_exhaust_compound.scala @@ -0,0 +1,29 @@ +sealed trait Base +case object O1 extends Base +case object O2 extends Base { + def foo: Int = 0 +} + +sealed trait Base2 +case object O3 extends Base2 + +case object O4 extends Base with Base2 + +object Test { + val a /*: Product with Serialiable with Base */ = if (true) O1 else O2 + a match { + case null => + } + + def t1(a: Product with Base with Base2) = a match { + case null => // O1..O3 should *not* be possible here + } + + def t2(a: Product with Base { def foo: Int }) = a match { + case null => // O2 in the domain + } + + def t3(a: Product with Base { def bar: Int }) = a match { + case null => // nothing in the domain + } +} |