diff -r 7fe655cad9b1 -r 6b48ebae2569 src/share/classes/com/sun/tools/javac/code/Types.java
--- a/src/share/classes/com/sun/tools/javac/code/Types.java	Tue Jun 11 09:59:34 2013 +0100
+++ b/src/share/classes/com/sun/tools/javac/code/Types.java	Fri Jun 14 16:25:09 2013 +0100
@@ -951,6 +951,22 @@
     }
 
     /**
+    * A polymorphic signature method (JLS SE 7, 8.4.1) is a method that
+    * (i) is declared in the java.lang.invoke.MethodHandle class, (ii) takes
+    * a single variable arity parameter (iii) whose declared type is Object[],
+    * (iv) has a return type of Object and (v) is native.
+    */
+   public boolean isSignaturePolymorphic(MethodSymbol msym) {
+       List<Type> argtypes = msym.type.getParameterTypes();
+       return (msym.flags_field & NATIVE) != 0 &&
+               msym.owner == syms.methodHandleType.tsym &&
+               argtypes.tail.tail == null &&
+               argtypes.head.hasTag(TypeTag.ARRAY) &&
+               msym.type.getReturnType().tsym == syms.objectType.tsym &&
+               ((ArrayType)argtypes.head).elemtype.tsym == syms.objectType.tsym;
+   }
+
+    /**
      * Is t the same type as s?
      */
     public boolean isSameType(Type t, Type s) {