diff options
5 files changed, 43 insertions, 16 deletions
diff --git a/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala b/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala index 74b932e173..d9f93f27b6 100644 --- a/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala +++ b/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala @@ -691,11 +691,13 @@ trait MatchAnalysis extends MatchApproximation { VariableAssignment(scrutVar).toCounterExample() } - def analyzeCases(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type, unchecked: Boolean): Unit = { - unreachableCase(prevBinder, cases, pt) foreach { caseIndex => - reportUnreachable(cases(caseIndex).last.pos) + def analyzeCases(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type, suppression: Suppression): Unit = { + if (!suppression.unreachable) { + unreachableCase(prevBinder, cases, pt) foreach { caseIndex => + reportUnreachable(cases(caseIndex).last.pos) + } } - if (!unchecked) { + if (!suppression.exhaustive) { val counterExamples = exhaustive(prevBinder, cases, pt) if (counterExamples.nonEmpty) reportMissingCases(prevBinder.pos, counterExamples) diff --git a/src/compiler/scala/tools/nsc/transform/patmat/MatchTreeMaking.scala b/src/compiler/scala/tools/nsc/transform/patmat/MatchTreeMaking.scala index 51f21780b5..202f3444f8 100644 --- a/src/compiler/scala/tools/nsc/transform/patmat/MatchTreeMaking.scala +++ b/src/compiler/scala/tools/nsc/transform/patmat/MatchTreeMaking.scala @@ -23,16 +23,21 @@ trait MatchTreeMaking extends MatchCodeGen with Debugging { import global.{Tree, Type, Symbol, CaseDef, atPos, settings, Select, Block, ThisType, SingleType, NoPrefix, NoType, needsOuterTest, ConstantType, Literal, Constant, gen, This, EmptyTree, map2, NoSymbol, Traverser, - Function, Typed, treeInfo, TypeRef, DefTree} + Function, Typed, treeInfo, TypeRef, DefTree, Ident, nme} import global.definitions.{SomeClass, AnyRefClass, UncheckedClass, BooleanClass} + final case class Suppression(exhaustive: Boolean, unreachable: Boolean) + object Suppression { + val NoSuppression = Suppression(false, false) + } + /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // the making of the trees /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// trait TreeMakers extends TypedSubstitution with CodegenCore { def optimizeCases(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type): (List[List[TreeMaker]], List[Tree]) - def analyzeCases(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type, unchecked: Boolean): Unit + def analyzeCases(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type, suppression: Suppression): Unit def emitSwitch(scrut: Tree, scrutSym: Symbol, cases: List[List[TreeMaker]], pt: Type, matchFailGenOverride: Option[Tree => Tree], unchecked: Boolean): Option[Tree] = None @@ -522,18 +527,24 @@ trait MatchTreeMaking extends MatchCodeGen with Debugging { def matchFailGen = (matchFailGenOverride orElse Some(CODE.MATCHERROR(_: Tree))) debug.patmat("combining cases: "+ (casesNoSubstOnly.map(_.mkString(" >> ")).mkString("{", "\n", "}"))) - val (unchecked, requireSwitch) = - if (settings.XnoPatmatAnalysis.value) (true, false) + val (suppression, requireSwitch): (Suppression, Boolean) = + if (settings.XnoPatmatAnalysis.value) (Suppression.NoSuppression, false) else scrut match { - case Typed(_, tpt) => - (tpt.tpe hasAnnotation UncheckedClass, - // matches with two or fewer cases need not apply for switchiness (if-then-else will do) - treeInfo.isSwitchAnnotation(tpt.tpe) && casesNoSubstOnly.lengthCompare(2) > 0) + case Typed(tree, tpt) => + val suppressExhaustive = tpt.tpe hasAnnotation UncheckedClass + val supressUnreachable = tree match { + case Ident(name) if name startsWith nme.CHECK_IF_REFUTABLE_STRING => true // SI-7183 don't warn for withFilter's that turn out to be irrefutable. + case _ => false + } + val suppression = Suppression(suppressExhaustive, supressUnreachable) + // matches with two or fewer cases need not apply for switchiness (if-then-else will do) + val requireSwitch = treeInfo.isSwitchAnnotation(tpt.tpe) && casesNoSubstOnly.lengthCompare(2) > 0 + (suppression, requireSwitch) case _ => - (false, false) + (Suppression.NoSuppression, false) } - emitSwitch(scrut, scrutSym, casesNoSubstOnly, pt, matchFailGenOverride, unchecked).getOrElse{ + emitSwitch(scrut, scrutSym, casesNoSubstOnly, pt, matchFailGenOverride, suppression.exhaustive).getOrElse{ if (requireSwitch) typer.context.unit.warning(scrut.pos, "could not emit switch for @switch annotated match") if (casesNoSubstOnly nonEmpty) { @@ -550,7 +561,7 @@ trait MatchTreeMaking extends MatchCodeGen with Debugging { }) None else matchFailGen - analyzeCases(scrutSym, casesNoSubstOnly, pt, unchecked) + analyzeCases(scrutSym, casesNoSubstOnly, pt, suppression) val (cases, toHoist) = optimizeCases(scrutSym, casesNoSubstOnly, pt) diff --git a/src/compiler/scala/tools/nsc/transform/patmat/PatternMatching.scala b/src/compiler/scala/tools/nsc/transform/patmat/PatternMatching.scala index f8d8044bdb..df4e699620 100644 --- a/src/compiler/scala/tools/nsc/transform/patmat/PatternMatching.scala +++ b/src/compiler/scala/tools/nsc/transform/patmat/PatternMatching.scala @@ -81,7 +81,7 @@ trait PatternMatching extends Transform with TypingTransformers class PureMatchTranslator(val typer: analyzer.Typer, val matchStrategy: Tree) extends MatchTranslator with PureCodegen { def optimizeCases(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type) = (cases, Nil) - def analyzeCases(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type, unchecked: Boolean): Unit = {} + def analyzeCases(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type, suppression: Suppression): Unit = {} } class OptimizingMatchTranslator(val typer: analyzer.Typer) extends MatchTranslator diff --git a/test/files/pos/t7183.flags b/test/files/pos/t7183.flags new file mode 100644 index 0000000000..e8fb65d50c --- /dev/null +++ b/test/files/pos/t7183.flags @@ -0,0 +1 @@ +-Xfatal-warnings
\ No newline at end of file diff --git a/test/files/pos/t7183.scala b/test/files/pos/t7183.scala new file mode 100644 index 0000000000..7647c1634b --- /dev/null +++ b/test/files/pos/t7183.scala @@ -0,0 +1,13 @@ +class A +object A { + def unapply(a: A): Some[A] = Some(a) // Change return type to Option[A] and the warning is gone +} + +object Test { + for (A(a) <- List(new A)) yield a // spurious dead code warning. +} + +// List(new A()).withFilter(((check$ifrefutable$2) => check$ifrefutable$2: @scala.unchecked match { +// case A((a @ _)) => true +// case _ => false // this is dead code, but it's compiler generated. +// })) |