--- a/langtools/src/share/classes/com/sun/tools/javac/comp/Check.java	Tue Jun 18 20:56:04 2013 -0700
+++ b/langtools/src/share/classes/com/sun/tools/javac/comp/Check.java	Wed Jun 19 11:48:05 2013 +0100
@@ -2267,6 +2267,24 @@
         c.flags_field |= ACYCLIC;
     }
 
+    /**
+     * Check that functional interface methods would make sense when seen
+     * from the perspective of the implementing class
+     */
+    void checkFunctionalInterface(JCTree tree, Type funcInterface) {
+        ClassType c = new ClassType(Type.noType, List.<Type>nil(), null);
+        ClassSymbol csym = new ClassSymbol(0, names.empty, c, syms.noSymbol);
+        c.interfaces_field = List.of(types.removeWildcards(funcInterface));
+        c.supertype_field = syms.objectType;
+        c.tsym = csym;
+        csym.members_field = new Scope(csym);
+        Symbol descSym = types.findDescriptorSymbol(funcInterface.tsym);
+        Type descType = types.findDescriptorType(funcInterface);
+        csym.members_field.enter(new MethodSymbol(PUBLIC, descSym.name, descType, csym));
+        csym.completer = null;
+        checkImplementations(tree, csym, csym);
+    }
+
     /** Check that all methods which implement some
      *  method conform to the method they implement.
      *  @param tree         The class definition whose members are checked.