Merge pull request #72142 from DougGregor/preinversegenerics-extensions

Allow @_preInverseGenerics on extensions

Author: DougGregor

include/swift/AST/ASTMangler.h

@@ -479,6 +479,9 @@ class ASTMangler : public Mangler {
     BaseEntitySignature(const Decl *decl);
   };
 
+  static bool inversesAllowed(const Decl *decl);
+  static bool inversesAllowedIn(const DeclContext *ctx);
+
   void appendContextOf(const ValueDecl *decl, BaseEntitySignature &base);
   void appendContextualInverses(const GenericTypeDecl *contextDecl,
                                 BaseEntitySignature &base,

include/swift/AST/DeclAttr.def

@@ -492,7 +492,7 @@ DECL_ATTR(_allowFeatureSuppression, AllowFeatureSuppression,
   OnAnyDecl | UserInaccessible | NotSerialized | ABIStableToAdd | APIStableToAdd | ABIStableToRemove | APIStableToRemove,
   157)
 SIMPLE_DECL_ATTR(_preInverseGenerics, PreInverseGenerics,
-  OnAbstractFunction | OnSubscript | OnVar | UserInaccessible | ABIBreakingToAdd | ABIBreakingToRemove | APIStableToAdd | APIStableToRemove,
+  OnAbstractFunction | OnSubscript | OnVar | OnExtension | UserInaccessible | ABIBreakingToAdd | ABIBreakingToRemove | APIStableToAdd | APIStableToRemove,
   158)
 LAST_DECL_ATTR(PreInverseGenerics)
 

lib/AST/ASTMangler.cpp

@@ -62,7 +62,7 @@
 using namespace swift;
 using namespace swift::Mangle;
 
-static bool inversesAllowed(const Decl *decl) {
+bool ASTMangler::inversesAllowed(const Decl *decl) {
   if (!decl)
     return true;
 
@@ -73,7 +73,7 @@ static bool inversesAllowed(const Decl *decl) {
   return !decl->getAttrs().hasAttribute<PreInverseGenericsAttr>();
 }
 
-static bool inversesAllowedIn(const DeclContext *ctx) {
+bool ASTMangler::inversesAllowedIn(const DeclContext *ctx) {
   assert(ctx);
   return inversesAllowed(ctx->getInnermostDeclarationDeclContext());
 }
@@ -242,6 +242,9 @@ std::string ASTMangler::mangleConstructorVTableThunk(
 }
 
 std::string ASTMangler::mangleWitnessTable(const RootProtocolConformance *C) {
+  llvm::SaveAndRestore X(AllowInverses,
+                         inversesAllowedIn(C->getDeclContext()));
+
   beginMangling();
   if (isa<NormalProtocolConformance>(C)) {
     appendProtocolConformance(C);

lib/IRGen/IRGenMangler.cpp

@@ -197,6 +197,9 @@ IRGenMangler::mangleTypeForFlatUniqueTypeRef(CanGenericSignature sig,
 
 std::string IRGenMangler::mangleProtocolConformanceDescriptor(
                                  const RootProtocolConformance *conformance) {
+  llvm::SaveAndRestore X(AllowInverses,
+                         inversesAllowedIn(conformance->getDeclContext()));
+
   beginMangling();
   if (isa<NormalProtocolConformance>(conformance)) {
     appendProtocolConformance(conformance);