The fix for -explaintypes having gone off the d...

The fix for -explaintypes having gone off the deep end. Perhaps other
good may come of it as well. Review by odersky.

1 files changed, 7 insertions, 5 deletions

diff --git a/src/compiler/scala/tools/nsc/symtab/Definitions.scala b/src/compiler/scala/tools/nsc/symtab/Definitions.scala
index 5f9696c71d..28ef540ff0 100644
--- a/src/compiler/scala/tools/nsc/symtab/Definitions.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Definitions.scala
@@ -311,11 +311,13 @@ trait Definitions extends reflect.generic.StandardDefinitions {
       def tupleField(n: Int, j: Int) = getMember(TupleClass(n), "_" + j)
       def isTupleType(tp: Type): Boolean = isTupleType(tp, false)
       def isTupleTypeOrSubtype(tp: Type): Boolean = isTupleType(tp, true)
-      private def isTupleType(tp: Type, subtypeOK: Boolean): Boolean = cond(tp.normalize) {
-        case t @ TypeRef(_, sym, elems) =>
-          elems.length <= MaxTupleArity &&
-          (sym == TupleClass(elems.length) ||
-           subtypeOK && !tp.isHigherKinded && (t <:< TupleClass(elems.length).tpe))
+      private def isTupleType(tp: Type, subtypeOK: Boolean) = tp.normalize match {
+        case TypeRef(_, sym, args) =>
+          args.length <= MaxTupleArity && {
+            val tsym = TupleClass(args.length)
+            (sym == tsym) || (subtypeOK && !tp.isHigherKinded && sym.isSubClass(tsym))
+          }
+        case _ => false
       }
 
       def tupleType(elems: List[Type]) =