Three problems are fixed:
- I forgot to pass the `downwards` flag when doing downwards inference.
- I forgot to initialize the `formalTypes` and `actualTypes` arrays.
- I wasn't tracking whether constructor type arguments were implicit
or explicit, so constructor type inference wasn't actually
happening.
R=scheglov@google.com
Review-Url: https://codereview.chromium.org/2864853002 .
Paul Berry
4eee6cb5ea