code: public com.sun.javadoc.Type overriddenType() {
  
          if ((sym.flags() & Flags.STATIC) != 0) {
              return null;
          }
  
          ClassSymbol origin = (ClassSymbol)sym.owner;
          for (Type t = env.types.supertype(origin.type);
               t.hasTag(CLASS);
               t = env.types.supertype(t)) {
              ClassSymbol c = (ClassSymbol)t.tsym;
              for (Symbol sym2 : membersOf(c).getSymbolsByName(sym.name)) {
                  if (sym.overrides(sym2, origin, env.types, true)) {
                      return TypeMaker.getType(env, t);
                  }
              }
          }
          return null;
      }
docs: Return the type containing the method that this method overrides.
  It may be a <code>ClassDoc</code> or a <code>ParameterizedType</code>.