diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/compiler/scala/tools/nsc/matching/MatrixAdditions.scala | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/src/compiler/scala/tools/nsc/matching/MatrixAdditions.scala b/src/compiler/scala/tools/nsc/matching/MatrixAdditions.scala index 6141b2333c..b880dea858 100644 --- a/src/compiler/scala/tools/nsc/matching/MatrixAdditions.scala +++ b/src/compiler/scala/tools/nsc/matching/MatrixAdditions.scala @@ -173,19 +173,24 @@ trait MatrixAdditions extends ast.TreeDSL private def rowCoversCombo(row: Row, combos: List[Combo]) = row.guard.isEmpty && (combos forall (c => c isCovered row.pats(c.index))) - private def requiresExhaustive(s: Symbol) = { - (s hasFlag MUTABLE) && // indicates that have not yet checked exhaustivity - !(s hasFlag TRANS_FLAG) && // indicates @unchecked - (s.tpe.typeSymbol.isSealed) && { - s resetFlag MUTABLE // side effects MUTABLE flag - !isValueClass(s.tpe.typeSymbol) // but make sure it's not a primitive, else (5: Byte) match { case 5 => ... } sees no Byte - } + private def requiresExhaustive(sym: Symbol) = { + (sym.isMutable) && // indicates that have not yet checked exhaustivity + !(sym hasFlag TRANS_FLAG) && // indicates @unchecked + (sym.tpe.typeSymbol.isSealed) && + !isValueClass(sym.tpe.typeSymbol) // make sure it's not a primitive, else (5: Byte) match { case 5 => ... } sees no Byte } private lazy val inexhaustives: List[List[Combo]] = { - val collected = - for ((pv, i) <- tvars.zipWithIndex ; val sym = pv.lhs ; if requiresExhaustive(sym)) yield - i -> sym.tpe.typeSymbol.sealedDescendants + // let's please not get too clever side-effecting the mutable flag. + val toCollect = tvars.zipWithIndex filter { case (pv, i) => requiresExhaustive(pv.sym) } + val collected = toCollect map { case (pv, i) => + // okay, now reset the flag + pv.sym resetFlag MUTABLE + // have to filter out children which cannot match: see ticket #3683 for an example + val kids = pv.tpe.typeSymbol.sealedDescendants filter (_.tpe matchesPattern pv.tpe) + + i -> kids + } val folded = collected.foldRight(List[List[Combo]]())((c, xs) => { |