Please forgive me if this appears more like a rant than a feature request, but I have searched and can't find any explanation for why some error messages are displayed without any `displayName` from the component responsible - and this is driving me insane.

_Every_ component in my project has an explicit `displayName` specified.  I do this for debugging.

I am rendering a bunch of immutable props.  I changed one of the prop types from a `List` to a `Map` and I see:

> Warning: Using Maps as children is not yet fully supported. It is an experimental feature that might be removed. Convert it to a sequence / iterable of keyed ReactElements instead.

Obviously I missed something, which could be easily fixed if I knew _where_ it was - even just the component's name.

This message is not only frustrating, but it's taunting "I know where the problem is but I won't tell you!"-feel makes it infuriating.  Looking at the stacktrace behind it is useless as well because it's, as usual, a never-ending list of React function calls with no mention of any of my source files.

I have spent countless time hunting down errors like this that would have taken only moments if I knew the name of the component responsible.  It would be _infinitely more helpful_ if the `displayName` field appeared in more debug output.

nextName,
            callback,
            traverseContext
          );
        }
      } else {
        if (__DEV__) {
          warning(
            didWarnAboutMaps,
            'Using Maps as children is not yet fully supported. It is an ' +
            'experimental feature that might be removed. Convert it to a ' +
            'sequence / iterable of keyed ReactElements instead.'
          );
          didWarnAboutMaps = true;
        }
        
        while (!(step = iterator.next()).done) {
          var entry = step.value;
          if (entry) {
            child = entry[1];
            nextName = (
              nextNamePrefix +
              KeyEscapeUtils.escape(entry[0]) + SUBSEPARATOR +
              getComponentKey(child, 0)
            );
            subtreeCount += traverseAllChildrenImpl(
              child,
              nextName,
              callback,
              traverseContext