ClassElement.allSupertypes getter is missing results

[jmesserly]

It does not appear to visit interfaces of mixins.

This looks mainly like it affects analysis_server; analyzer itself only uses the getter for protected member checking, so it probably doesn't come up much.

[kevmoo]

Bumping the priority. Just hit this looking at UnmodifiableListView – no List or Iterable.

Guessing this implementation is not digging into implementations of the Mixins?

Since this is exposed on ClassElement, it can affect any user of the Analyzer API – so the pain goes beyond analysis server

[bwilkerson]

https://codereview.chromium.org/3000183002/