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don't check exhaustivity involving user-defined unapplySeq

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adriaanm committed May 24, 2012
1 parent bcc8280 commit fddd576b1183e394cdfb47f074fe7918a37644b6
@@ -1973,6 +1973,7 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL
case Some(0) if testedBinder.tpe.typeSymbol == ListClass => // extractor.symbol.owner == SeqFactory
EqualityCond(binderToUniqueTree(p.prevBinder), unique(Ident(NilModule) setType NilModule.tpe))
case _ =>
backoff = true
super.treeMakerToCond(tm)
}
case ExtractorTreeMaker(_, _, _, _) =>
@@ -18,10 +18,6 @@ patmatexhaust.scala:53: error: match may not be exhaustive.
It would fail on the following input: Gp()
def ma5(x:Deep) = x match {
^
patmatexhaust.scala:59: error: match may not be exhaustive.
It would fail on the following input: Nil
def ma6() = List(1,2) match { // give up
^
patmatexhaust.scala:75: error: match may not be exhaustive.
It would fail on the following input: B()
def ma9(x: B) = x match {
@@ -38,4 +34,4 @@ patmatexhaust.scala:126: error: match may not be exhaustive.
It would fail on the following input: C1()
def ma10(x: C) = x match { // not exhaustive: C1 is not abstract.
^
10 errors found
9 errors found
@@ -12,5 +12,15 @@ object Test {
case _ if turnOffChecks =>
}
// TODO: we back off when there are any user-defined extractors
// we back off when there are any user-defined extractors
// in fact this is exhaustive, but we pretend we don't know since List's unapplySeq is not special to the compiler
// to compensate our ignorance, we back off
// well, in truth, we do rewrite List() to Nil, but otherwise we do nothing
// the full rewrite List(a, b) to a :: b :: Nil, for example is planned (but not sure it's a good idea)
List(true, false) match {
case List(_, _, _*) =>
case List(node, _*) =>
case Nil =>
}
}

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