Clean up duplicated opened existential archetype handling in SIL and more #81142
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Let's use transformRec() instead of subst() here since we want to leave DependentMemberTypes unchanged. This avoids an assertion failure with the upcoming change to InFlightSubstitution::lookupConformance().
The special handling of DynamicSelfType should no longer be necessary so I'm removing it.
This replaces the oddly-named mapIntoTypeExpansionContext() method on SubstitutionMap itself in favor of a global function, just like the ones that take Type and ProtocolConformanceRef.
slavapestov
requested review from
hborla,
xedin,
ktoso,
eeckstein,
jckarter,
rjmccall and
tshortli
as code owners
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@swift-ci Please test source compatibility |
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swiftlang/llvm-project#10587 |
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I noticed that SIL had three copy and pasted implementations of the algorithm for replacing opened existential archetypes with concrete types. This optimization comes up if inlining produces an existential value formed from a concrete type which is then immediately opened; we can eliminate the existential archetype in that case. However, this bit of copy and paste predated the introduction of generalized existentials, so it did not handle member types at all. This is a potential landmine if it ends up being used in more places in SIL.
This PR factors out one of the duplicate copies into a new "official"
ReplaceExistentialArchetypesWithConcreteTypes, analogous to the transformer used for opaque archetypes. The new version is more complicated but it handles existential archetypes in full generality now. The other duplicate copy was a special case of an existing utility inSILCloner, and the third one was dead.