swift

2ef9363b - [ABI] Add default associated type witnesses to resilient protocols.

[ABI] Add default associated type witnesses to resilient protocols. When an associated type witness has a default, record that as part of the protocol and emit a default associated type metadata accessor into the default witness table. This allows a defaulted associated type to be added to a protocol resiliently. This is another part of rdar://problem/44167982, but it’s still very limiting because the new associated type cannot have any conformances.