swift234

Check user-written functions before looking at any imported types.

User-written functions can trigger the use of delayed protocols on imported
types. In the case of enums and structs, it's possible that we need to
synthesize a conformance for one of these protocols. We were failing to do
so because we were checking imported types before looking at any user code,
and deciding not to bother with the delayed protocols because no one had
referenced them yet.

This isn't necessarily a good long-term solution because it doesn't handle
implicitly-defined functions triggering the use of implicit conformances
on imported types. The general problem of "this enum was never compared
so I never made an Equatable performance" is still there, just much less
likely (since our synthesized declarations are usually quite simple). We
may want to revisit this later to make it more robust.

I also couldn't find a reduced test case that triggered this issue. The
reported code looks very similar to the test case I added, but the one I
added doesn't actually fail before this commit. I'm including it anyway to
guard against regressions.

rdar://problem/18198880

Swift SVN r21840