[Name lookup] Use decl-based name lookup for protocol-related queries #18530
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…able. Add API to get all of the nominal types directly referenced from the inheritance clause of a given declaration. Use that to find the protocols to enter into the conformance lookup table based on a given declaration, without going through the type checker [*]. [*] Except for unqualified lookup still needing to use the type checker.
…ion. Resolving whether a protocol is class-bound only requires declaration-based resolution (not the full type checker), so switch over to those APIs.
…lookup. Use the declaration-based name lookup facilities to re-implement ProtocolDecl::getInheritedProtocols(), rather than dynamically selecting between the requirement signature and the inherited types. This reduces dependencies for this computation down to basic name lookup (no semantic analysis) and gives us a stable result.
Ensuring that we've computed the list of "inherited" protocols is part of finalizeType(), now.
…heritedType(). Simple checks for the presence of a protocol in the “inherited” list should only require a scan through that list + name lookup; use those facilities instead of recursing through the type checker.
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@swift-ci please smoke test |
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@swift-ci please test source compatibility |
| struct S4 : P, P { } // expected-error {{duplicate inheritance from 'P'}} | ||
| struct S4 : P, P { } // FIXME: expected-error {{duplicate inheritance from 'P'}} | ||
| // expected-error@-1{{redundant conformance of 'S4' to protocol 'P'}} | ||
| // expected-note@-2{{'S4' declares conformance to protocol 'P' here}} |
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I think the duplicate diagnostics come from checkInheritanceClause() and the GSB, respectively
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Yeah. I'm going to narrow the one in checkInheritanceClause() to eliminate the duplication. See #18700
| nominalDecls.insert(nominalDecls.end(), | ||
| underlyingNominalReferences.begin(), | ||
| underlyingNominalReferences.end()); | ||
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| // Recognize Swift.AnyObject directly. |
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Swift.AnyObject should have been deserialized and type checked -- would that make this simpler?
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No, it doesn't, because we need this check to work when building the standard library, and don't want to rely on Swift.AnyObject having been type-checked first.
include/swift/AST/NameLookup.h
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| @@ -356,18 +356,23 @@ void lookupInModule(ModuleDecl *module, ModuleDecl::AccessPathTy accessPath, | |||
| /// "inherited" by the given declaration at a particular position in the | |||
| /// list of "inherited" types. | |||
| /// | |||
| /// Add anything we find to the | |||
| /// Add anything we find to the \c result vector. If we come across the | |||
| /// AnyObject type, set \c anyObject true. | |||
| void getDirectlyInheritedNominalTypeDecls( | |||
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Would it be cleaner to return a struct or a pair here instead of having two out parameters?
| @@ -592,10 +592,6 @@ ModuleDecl::lookupConformance(Type type, ProtocolDecl *protocol) { | |||
| // existential's list of conformances and the existential conforms to | |||
| // itself. | |||
| if (type->isExistentialType()) { | |||
| // FIXME: Recursion break. | |||
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Are you sure this is not needed? existentialConformsToSelf() can call back into validateDecl() IIRC
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No longer! It uses simpler queries that don't go through validateDecl(), now that getInheritedProtocols() is all decl-lookup-based.
lib/AST/NameLookup.cpp
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| @@ -1966,7 +1966,8 @@ resolveTypeDeclsToNominal(Evaluator &evaluator, | |||
| ASTContext &ctx, | |||
| ArrayRef<TypeDecl *> typeDecls, | |||
| SmallVectorImpl<ModuleDecl *> &modulesFound, | |||
| bool &anyObject) { | |||
| bool &anyObject, | |||
| llvm::SmallPtrSetImpl<TypeAliasDecl *> &typealiases) { | |||
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Even more reason to use a real return type :)
| @@ -91,6 +91,16 @@ ProtocolDecl *DeclContext::getAsProtocolExtensionContext() const { | |||
| GenericTypeParamType *DeclContext::getProtocolSelfType() const { | |||
| assert(getAsProtocolOrProtocolExtensionContext() && "not a protocol"); | |||
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| auto genericParams = getGenericParamsOfContext(); | |||
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ProtocolDecl::createGenericParamsIfMissing() is lighter weight
Use the decl-base name lookup facilities (that don't recurse into the type checker) for various protocol-related queries, including:
ProtocolDecl::requiresClass(), which determines whether a given protocol is class-boundProtocolDecl::getInheritedProtocols(), which would bounce between using the requirement signature and using the type checker.