Unchecked cast unchecked?

[Archie Cobbs]

Question: Should this program generate an unchecked cast warning?

import java.lang.invoke.VarHandle;
class VarHandleCast<V> {
    VarHandle vh;
    V method(Object obj) {
        return (V)vh.getAndSet(this, obj);  // unchecked cast?
    }
}

Currently, it does not.

Presumably that has something to do with this code in Types.java but I'm
not sure why this would mean there should be no warning:

    /**
     * A polymorphic signature method (JLS 15.12.3) is a method that
     *   (i) is declared in the java.lang.invoke.MethodHandle/VarHandle
classes;
     *  (ii) takes a single variable arity parameter;
     * (iii) whose declared type is Object[];
     *  (iv) has any return type, Object signifying a polymorphic return
type; 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 || msym.owner ==
syms.varHandleType.tsym) &&
               argtypes.length() == 1 &&
               argtypes.head.hasTag(TypeTag.ARRAY) &&
               ((ArrayType)argtypes.head).elemtype.tsym ==
syms.objectType.tsym;
   }

Thanks,
-Archie

-- 
Archie L. Cobbs
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.openjdk.org/pipermail/compiler-dev/attachments/20241029/d73cd512/attachment.htm>