swift234

SILGen: Include refined protocol conformances in witness tables.

When a type conforms to a protocol that refines another protocol, emit the witness table for the base protocol, and drop a reference into the witness table for the derived protocol. Keep track of what conformances we've already emitted so we don't emit redundant witness tables when types conform redundantly to base protocols or have multiple references to a base protocol via a refinement diamond.

Swift SVN r11263