swift

6a378779 - Teach the old associated type inference about AsyncSequence.Failure

Teach the old associated type inference about AsyncSequence.Failure The new one is smart enough to figure out a type witness for AsyncSequence.Failure from AsyncSequence.AsyncIterator.Failure, but the old one doesn't have general logic to handle cases like these. Introduce a bespoke rule to keep the old/new associated type inference logic in sync for the newly-introduced Failure type.