code: function identifier(fnparam, prop) {
      var i = optionalidentifier(fnparam, prop);
      if (i) {
        return i;
      }
      if (state.tokens.curr.id === "function" && state.tokens.next.id === "(") {
        warning("W025");
      } else {
        error("E030", state.tokens.next, state.tokens.next.value);
      }
    }
docs: fnparam means that this identifier is being defined as a function argument prop means that this identifier is that of an object property