function warnSetProps() {
  if (!warnedSetProps) {
    warnedSetProps = true;
    "development" !== 'production' ? warning(false, 'setProps(...) and replaceProps(...) are deprecated. ' + 'Instead, call render again at the top level.') : undefined;
  }
}
These methods are similar to DEFINE_MANY, except we assume they return
objects. We try to merge the keys of the return values of all the mixed in
functions. If there is a key conflict we throw.