code: public boolean recordBaseType(JSTypeExpression jsType) {
      if (jsType != null && !hasAnySingletonTypeTags() &&
          !currentInfo.hasBaseType()) {
        currentInfo.setBaseType(jsType);
        populated = true;
        return true;
      } else {
        return false;
      }
    }
docs: Records a base type.
  
  @return {@code true} if the base type was recorded and {@code false}
  if it was already defined