Corrects behavior of finalResultType.

The implementation had come to depend on finalResultType
accidentally doing things beyond its charter - in particular,
widening types. After hunting down and fixing the call sites
depending on the bugs, I was able to rewrite the method to do
only what it's supposed to do.

I threw in a different way of writing it entirely to suggest how
some correctness might be obtained in the future. It's a lot
harder for a method written like this to break.

1 files changed, 5 insertions, 4 deletions

diff --git a/src/compiler/scala/tools/nsc/transform/UnCurry.scala b/src/compiler/scala/tools/nsc/transform/UnCurry.scala
index 16c803e2e8..93a36f8f01 100644
--- a/src/compiler/scala/tools/nsc/transform/UnCurry.scala
+++ b/src/compiler/scala/tools/nsc/transform/UnCurry.scala
@@ -158,11 +158,12 @@ abstract class UnCurry extends InfoTransform
      */
     private def nonLocalReturnTry(body: Tree, key: Symbol, meth: Symbol) = {
       localTyper typed {
-        val extpe   = nonLocalReturnExceptionType(meth.tpe.finalResultType)
+        val restpe  = meth.tpe_*.finalResultType
+        val extpe   = nonLocalReturnExceptionType(restpe)
         val ex      = meth.newValue(nme.ex, body.pos) setInfo extpe
-        val argType = meth.tpe.finalResultType withAnnotation (AnnotationInfo marker UncheckedClass.tpe)
+        val argType = restpe withAnnotation (AnnotationInfo marker UncheckedClass.tpe)
         val pat     = gen.mkBindForCase(ex, NonLocalReturnControlClass, List(argType))
-        val rhs = (
+        val rhs     = (
           IF   ((ex DOT nme.key)() OBJ_EQ Ident(key))
           THEN ((ex DOT nme.value)())
           ELSE (Throw(Ident(ex)))
@@ -739,7 +740,7 @@ abstract class UnCurry extends InfoTransform
         case p if rpsymbols(p.symbol) => toArrayType(p.symbol.tpe)
         case p                        => p.symbol.tpe
       }
-      val forwresult = dd.symbol.tpe.finalResultType
+      val forwresult = dd.symbol.tpe_*.finalResultType
       val forwformsyms = map2(forwformals, flatparams)((tp, oldparam) =>
         currentClass.newValueParameter(oldparam.name, oldparam.symbol.pos).setInfo(tp)
       )