diff options
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Typers.scala | 64 | ||||
| -rw-r--r-- | test/files/pos/t6029.scala | 3 |
2 files changed, 43 insertions, 24 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index 269ab9611a..b1c3249e35 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -1194,30 +1194,46 @@ trait Typers extends Modes with Adaptations with Tags { } val found = tree.tpe - val req = pt - if (!found.isErroneous && !req.isErroneous) { - if (!context.reportErrors && isPastTyper && req.skolemsExceptMethodTypeParams.nonEmpty) { - // Ignore type errors raised in later phases that are due to mismatching types with existential skolems - // We have lift crashing in 2.9 with an adapt failure in the pattern matcher. - // Here's my hypothsis why this happens. The pattern matcher defines a variable of type - // - // val x: T = expr - // - // where T is the type of expr, but T contains existential skolems ts. - // In that case, this value definition does not typecheck. - // The value definition - // - // val x: T forSome { ts } = expr - // - // would typecheck. Or one can simply leave out the type of the `val`: - // - // val x = expr - context.unit.warning(tree.pos, "recovering from existential Skolem type error in tree \n" + tree + "\nwith type " + tree.tpe + "\n expected type = " + pt + "\n context = " + context.tree) - adapt(tree, mode, deriveTypeWithWildcards(pt.skolemsExceptMethodTypeParams)(pt)) - } else { - // create an actual error - AdaptTypeError(tree, found, req) + if (!found.isErroneous && !pt.isErroneous) { + if (!context.reportErrors && isPastTyper) { + val (bound, req) = pt match { + case ExistentialType(qs, tpe) => (qs, tpe) + case _ => (Nil, pt) + } + val boundOrSkolems = bound ++ pt.skolemsExceptMethodTypeParams + if (boundOrSkolems.nonEmpty) { + // Ignore type errors raised in later phases that are due to mismatching types with existential skolems + // We have lift crashing in 2.9 with an adapt failure in the pattern matcher. + // Here's my hypothsis why this happens. The pattern matcher defines a variable of type + // + // val x: T = expr + // + // where T is the type of expr, but T contains existential skolems ts. + // In that case, this value definition does not typecheck. + // The value definition + // + // val x: T forSome { ts } = expr + // + // would typecheck. Or one can simply leave out the type of the `val`: + // + // val x = expr + // + // SI-6029 shows another case where we also fail (in uncurry), but this time the expected + // type is an existential type. + // + // The reason for both failures have to do with the way we (don't) transform + // skolem types along with the trees that contain them. We'd need a + // radically different approach to do it. But before investing a lot of time to + // to do this (I have already sunk 3 full days with in the end futile attempts + // to consistently transform skolems and fix 6029), I'd like to + // investigate ways to avoid skolems completely. + // + log("recovering from existential or skolem type error in tree \n" + tree + "\nwith type " + tree.tpe + "\n expected type = " + pt + "\n context = " + context.tree) + return adapt(tree, mode, deriveTypeWithWildcards(boundOrSkolems)(pt)) + } } + // create an actual error + AdaptTypeError(tree, found, pt) } setError(tree) } @@ -4531,7 +4547,7 @@ trait Typers extends Modes with Adaptations with Tags { assert(errorContainer == null, "Cannot set ambiguous error twice for identifier") errorContainer = tree } - + val fingerPrint: Long = name.fingerPrint var defSym: Symbol = tree.symbol // the directly found symbol diff --git a/test/files/pos/t6029.scala b/test/files/pos/t6029.scala new file mode 100644 index 0000000000..8f1bbb4ebf --- /dev/null +++ b/test/files/pos/t6029.scala @@ -0,0 +1,3 @@ +final case class V[A](x: A) extends AnyVal { + def flatMap[B](f: A => V[B]) = if (true) this else f(x) +} |