swift

aaa442bd - Always supersede conformances implied by pre-macro-expansion conformances

Always supersede conformances implied by pre-macro-expansion conformances Pre-macro-expansion conformances are introduced at the point where an attached extension macro is attached to a particular nominal type, and can imply other conformances. Once the macro is expanded, they are expected to be replaced by the real conformance from the extension produced by the macro. This includes any other conformances that are implied by that conformances. Ensure that the real conformance---and every conformances it implies---are considered "better" than the pre-expansion conformances. Fixes a bug where we would pick the wrong (pre-expansion) conformances, which would then fail to get fully type-checked prior to serialization. This could accept invalid code that then crashed the compiler, as in rdar://112916159. (cherry picked from commit ab576b31a75a09e84a132fde437d664f89d292c3) (cherry picked from commit 5fb5a2789b3e1bca7f1d0273b74f82c7d11837b9)