Slava Pestov 1f652bc7d8 Sema: Don't derive witnesses in swiftinterface files ...

This fixes a regression from https://github.com/apple/swift/pull/36752.

Previously, a RawRepresentable enum would use the default implementation
of == from a protocol extension in the standard library. After the above
PR, we began synthesizing the == operator, just like we do for ordinary
enums.

However, when type checking an older swiftinterface file, we would
still synthesize the declaration and try to use it, even though it would
not have existed in the older dylib built with the older compiler.

Fix this by not deriving witnesses in swiftinterface files at all.
The interface should already explicitly list out all derived witnesses;
if one is not listed, it should not be derived, because it does not
exist in the dylib.

Fixes rdar://problem/80466745.

2021-08-18 16:22:26 -04:00

2.0 KiB

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