void markInitialized(UninitializedType old) {
            Type newtype = old.initializedType();
            for (int i=0; i<stacksize; i++)
                if (stack[i] == old) stack[i] = newtype;
            for (int i=0; i<lvar.length; i++) {
                LocalVar lv = lvar[i];
                if (lv != null && lv.sym.type == old) {
                    VarSymbol sym = lv.sym;
                    sym = sym.clone(sym.owner);
                    sym.type = newtype;
                    LocalVar newlv = lvar[i] = new LocalVar(sym);
                    // should the following be initialized to cp?
                    newlv.start_pc = lv.start_pc;
                }
            }
        }