Protocol Witness Matching Mini-Manifesto

[DevAndArtist (Adrian Meister)]

Also I‘d love to see a generalization over Optional being a super type.

This is related:

@jrose

DevAndArtist:

• Would it make any sense to allow protocol requirement satisfaction with non-optional types, like with failable init's? (Probably with some implicit optional promotion.)

Yep, totally! Except for the part where this changes the behavior of existing code, so we'd have to be very careful about it. This is considered part of [SR-522] Protocol funcs cannot have covariant returns .