[5.7] RequirementMachine: Teach concrete contraction about nested associated types #58813
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Clean up the different cases by passing a 'Position' enum to substTypeParameter(). Also generalize it to work with arbitrary type parameters instead of generic parameters only, but leave this code path disabled for now.
…eters Fixes rdar://problem/91594361.
…ignature completion fails - If P is declared to inherit from Q and Q has an associated type named U, then isValidTypeInContext() returns true for a type 'T.U' where 'T' is a generic parameter conforming to P, and 'U' is the unresolved DependentMemberType, and the type 'T.U' will simplify to the term 'T.[P:U]'. - However, if completion failed while building the rewrite system for P's requirement signature, then the requirement signature for P won't have a rule [P].[Q] => [P]. As a result, getTypeForTerm() will fail when given 'T.[P:U]', because the property map entry for 'T' will not contain a conformance to Q. Work around this by manually adding protocol inheritance rules when building a signature from a protocol whose requirement signature failed to compute. This was triggered by the test case I added in the previous commit to test/Generics/non_confluent.swift.
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@swift-ci Please test |
DougGregor
approved these changes
May 11, 2022
AnthonyLatsis
added
🍒 release cherry pick
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Cherry-pick of #58553
Concrete contraction is a hacky pre-processing pass to eliminate conformance
requirements that are made concrete; eg, if you have
We eliminate
T : PifG<U> : P.Generalize this to handle type parameters as well, so that
becomes
This fixes a regression with the test case in test/Generics/rdar91594361.swift.
Fixes rdar://problem/91594361.