2fa1143600
When a declared mixin is applied to a class, the class must implement the superclass constraint interfaces named in the mixin declaration. Change-Id: I6ace9fe244c1c87860b69c2c5e68f2c31ae73d7c Reviewed-on: https://dart-review.googlesource.com/c/79206 Commit-Queue: Kevin Millikin <kmillikin@google.com> Reviewed-by: Daniel Hillerström <hillerstrom@google.com>