Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Browse files

Merge pull request #1638 from adriaanm/ticket-6624

SI-6624 better lookup of case field accessors for case class pattern with complicated type
  • Loading branch information...
commit 888d0b4868a62c8d8288a4a8b639d282355ac33f 2 parents c81ef00 + 32c5732
@jsuereth jsuereth authored
View
12 src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala
@@ -417,7 +417,17 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL
// (the prefix of the argument passed to the unapply must equal the prefix of the type of the binder)
val treeMaker = TypeTestTreeMaker(patBinder, patBinder, extractor.paramType, extractor.paramType)(pos, extractorArgTypeTest = true)
(List(treeMaker), treeMaker.nextBinder)
- } else (Nil, patBinder)
+ } else {
+ // no type test needed, but the tree maker relies on `patBinderOrCasted` having type `extractor.paramType` (and not just some type compatible with it)
+ // SI-6624 shows this is necessary because apparently patBinder may have an unfortunate type (.decls don't have the case field accessors)
+ // TODO: get to the bottom of this -- I assume it happens when type checking infers a weird type for an unapply call
+ // by going back to the parameterType for the extractor call we get a saner type, so let's just do that for now
+ /* TODO: uncomment when `settings.developer` and `devWarning` become available
+ if (settings.developer.value && !(patBinder.info =:= extractor.paramType))
+ devWarning(s"resetting info of $patBinder: ${patBinder.info} to ${extractor.paramType}")
+ */
+ (Nil, patBinder setInfo extractor.paramType)
+ }
withSubPats(typeTestTreeMaker :+ extractor.treeMaker(patBinderOrCasted, pos), extractor.subBindersAndPatterns: _*)
}
View
28 test/files/pos/t6624.scala
@@ -0,0 +1,28 @@
+sealed trait KList[+M[_]]
+
+case class KCons[M[_], +T <: KList[M]](
+ tail: T
+) extends KList[M]
+
+case class KNil[M[_]]() extends KList[M]
+
+object Test {
+ val klist: KCons[Option, KCons[Option, KCons[Option, KNil[Nothing]]]] = ???
+
+ // crashes with
+ // "Exception in thread "main" scala.reflect.internal.Types$TypeError: value _1 is not a member
+ // of KCons[Option,KCons[Option,KNil[Nothing]]]"
+ klist match {
+ case KCons(KCons(KCons(_))) =>
+ }
+
+ // fails with a similar message as an error, rather than a crash.
+ klist match {
+ case KCons(KCons(_)) =>
+ }
+
+ // succeeds
+ klist match {
+ case KCons(_) =>
+ }
+}
Please sign in to comment.
Something went wrong with that request. Please try again.