void checkImplementations(JCClassDecl tree, ClassSymbol ic) {
            ClassSymbol origin = tree.sym;
            for (List<Type> l = types.closure(ic.type); l.nonEmpty(); l = l.tail) {
                ClassSymbol lc = (ClassSymbol)l.head.tsym;
                if ((allowGenerics || origin != lc) && (lc.flags() & ABSTRACT) != 0) {
                    for (Scope.Entry e=lc.members().elems; e != null; e=e.sibling) {
                        if (e.sym.kind == MTH &&
                            (e.sym.flags() & (STATIC|ABSTRACT)) == ABSTRACT) {
                            MethodSymbol absmeth = (MethodSymbol)e.sym;
                            MethodSymbol implmeth = absmeth.implementation(origin, types, false);
                            if (implmeth != null && implmeth != absmeth &&
                                (implmeth.owner.flags() & INTERFACE) ==
                                (origin.flags() & INTERFACE)) {
                                // don't check if implmeth is in a class, yet
                                // origin is an interface. This case arises only
                                // if implmeth is declared in Object. The reason is
                                // that interfaces really don't inherit from
                                // Object it's just that the compiler represents
                                // things that way.
                                checkOverride(tree, implmeth, absmeth, origin);
                            }
                        }
                    }
                }
            }
        }