code: public boolean isLintSet(String s) {
          // return true if either the specific option is enabled, or
          // they are all enabled without the specific one being
          // disabled
          return
              isSet(XLINT_CUSTOM, s) ||
              (isSet(XLINT) || isSet(XLINT_CUSTOM, "all")) && isUnset(XLINT_CUSTOM, "-" + s);
      }
docs: Check if the value for a lint option has been explicitly set, either with -Xlint:opt
  or if all lint options have enabled and this one not disabled with -Xlint:-opt.