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.

);
    expect(traverseFn).toHaveBeenCalledWith(
      traverseContext, <a key="a/.$aNode" />, '.2:$a/.$aNode'
    );
    expect(traverseFn).toHaveBeenCalledWith(
      traverseContext, 'string', '.3'
    );
    expect(traverseFn).toHaveBeenCalledWith(
      traverseContext, 1234, '.4'
    );
    expect(traverseFn).toHaveBeenCalledWith(
      traverseContext, null, '.5'
    );
    expect(traverseFn).toHaveBeenCalledWith(
      traverseContext, null, '.6'
    );
    expect(traverseFn).toHaveBeenCalledWith(
      traverseContext, null, '.7'
    );
    expect(traverseFn).toHaveBeenCalledWith(
      traverseContext, null, '.8'
    );
  });
  it('should be called for each child in nested structure', function() {
    var zero = <div key="keyZero" />;
    var one = null;
    var two = <div key="keyTwo" />;
    var three = null;
    var four = <div key="keyFour" />;
    var five = <div key="keyFiveInner" />;