diff -r 83c59a9d4b94 -r 1ca2dc8584e1 src/share/classes/com/sun/tools/javac/comp/Check.java
--- a/src/share/classes/com/sun/tools/javac/comp/Check.java	Tue Jan 20 17:49:09 2009 +0000
+++ b/src/share/classes/com/sun/tools/javac/comp/Check.java	Tue Jan 20 17:49:49 2009 +0000
@@ -1163,7 +1163,7 @@
 
         overrideWarner.warned = false;
         boolean resultTypesOK =
-            types.returnTypeSubstitutable(mt, ot, otres, overrideWarner);
+            types.covariantReturnType(mtres, otres, overrideWarner);
         if (!resultTypesOK) {
             if (!source.allowCovariantReturns() &&
                 m.owner != origin &&