AST: Clean up associated type default representation a bit

Author: slavapestov

include/swift/AST/Decl.h

@@ -3058,14 +3058,22 @@ class AssociatedTypeDecl : public AbstractTypeParamDecl {
     return cast<ProtocolDecl>(getDeclContext());
   }
 
+  /// Check if we have a default definition type.
+  bool hasDefaultDefinitionType() const {
+    // If we have a TypeRepr, return true immediately without kicking off
+    // a request.
+    return !DefaultDefinition.isNull() || getDefaultDefinitionType();
+  }
+
   /// Retrieve the default definition type.
-  Type getDefaultDefinitionType() const {
-    return getDefaultDefinitionLoc().getType();
+  Type getDefaultDefinitionType() const;
+
+  TypeLoc &getDefaultDefinitionLoc() {
+    return DefaultDefinition;
   }
 
-  TypeLoc &getDefaultDefinitionLoc();
   const TypeLoc &getDefaultDefinitionLoc() const {
-    return const_cast<AssociatedTypeDecl *>(this)->getDefaultDefinitionLoc();
+    return DefaultDefinition;
   }
 
   /// Retrieve the trailing where clause for this associated type, if any.
@@ -3076,7 +3084,7 @@ class AssociatedTypeDecl : public AbstractTypeParamDecl {
     TrailingWhere = trailingWhereClause;
   }
 
-  /// Set the interface type of this associated type declaration to a dependen
+  /// Set the interface type of this associated type declaration to a dependent
   /// member type of 'Self'.
   void computeType();
 

include/swift/AST/LazyResolver.h

@@ -159,8 +159,8 @@ class alignas(void*) LazyMemberLoader {
                       SmallVectorImpl<ProtocolConformance *> &Conformances) = 0;
 
   /// Returns the default definition type for \p ATD.
-  virtual TypeLoc loadAssociatedTypeDefault(const AssociatedTypeDecl *ATD,
-                                            uint64_t contextData) = 0;
+  virtual Type loadAssociatedTypeDefault(const AssociatedTypeDecl *ATD,
+                                         uint64_t contextData) = 0;
 
   /// Returns the generic environment.
   virtual GenericEnvironment *loadGenericEnvironment(const DeclContext *decl,

include/swift/Serialization/ModuleFile.h

@@ -827,8 +827,8 @@ class ModuleFile
   loadAllConformances(const Decl *D, uint64_t contextData,
                     SmallVectorImpl<ProtocolConformance*> &Conforms) override;
 
-  virtual TypeLoc loadAssociatedTypeDefault(const AssociatedTypeDecl *ATD,
-                                            uint64_t contextData) override;
+  virtual Type loadAssociatedTypeDefault(const AssociatedTypeDecl *ATD,
+                                         uint64_t contextData) override;
 
   virtual void finishNormalConformance(NormalProtocolConformance *conformance,
                                        uint64_t contextData) override;

lib/AST/ASTPrinter.cpp

@@ -2321,9 +2321,9 @@ void PrintAST::visitAssociatedTypeDecl(AssociatedTypeDecl *decl) {
     printInherited(decl);
   }
 
-  if (!decl->getDefaultDefinitionLoc().isNull()) {
+  if (decl->hasDefaultDefinitionType()) {
     Printer << " = ";
-    decl->getDefaultDefinitionLoc().getType().print(Printer, Options);
+    decl->getDefaultDefinitionType().print(Printer, Options);
   }
 
   // As with protocol's trailing where clauses, use the requirement signature

lib/AST/Decl.cpp

@@ -3526,13 +3526,14 @@ void AssociatedTypeDecl::computeType() {
   setInterfaceType(MetatypeType::get(interfaceTy, ctx));
 }
 
-TypeLoc &AssociatedTypeDecl::getDefaultDefinitionLoc() {
+Type AssociatedTypeDecl::getDefaultDefinitionType() const {
   if (Resolver) {
-    DefaultDefinition =
-      Resolver->loadAssociatedTypeDefault(this, ResolverContextData);
-    Resolver = nullptr;
+    const_cast<AssociatedTypeDecl *>(this)->DefaultDefinition
+      = TypeLoc::withoutLoc(
+        Resolver->loadAssociatedTypeDefault(this, ResolverContextData));
+    const_cast<AssociatedTypeDecl *>(this)->Resolver = nullptr;
   }
-  return DefaultDefinition;
+  return DefaultDefinition.getType();
 }
 
 SourceRange AssociatedTypeDecl::getSourceRange() const {

lib/AST/GenericSignatureBuilder.cpp

@@ -4282,7 +4282,7 @@ ConstraintResult GenericSignatureBuilder::expandConformanceRequirement(
         source->kind == RequirementSource::RequirementSignatureSelf &&
         !assocTypeDecl->getAttrs().hasAttribute<NonOverrideAttr>() &&
         !assocTypeDecl->getAttrs().hasAttribute<OverrideAttr>() &&
-        assocTypeDecl->getDefaultDefinitionLoc().isNull() &&
+        !assocTypeDecl->hasDefaultDefinitionType() &&
         (!assocTypeDecl->getInherited().empty() ||
          assocTypeDecl->getTrailingWhereClause() ||
          getASTContext().LangOpts.WarnImplicitOverrides);

lib/ClangImporter/ImporterImpl.h

@@ -1261,8 +1261,8 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
                                uint64_t unused) override;
 
   /// Returns the default definition type for \p ATD.
-  TypeLoc loadAssociatedTypeDefault(const AssociatedTypeDecl *ATD,
-                                            uint64_t contextData) override {
+  Type loadAssociatedTypeDefault(const AssociatedTypeDecl *ATD,
+                                 uint64_t contextData) override {
     llvm_unreachable("unimplemented for ClangImporter");
   }
 

lib/IDE/CodeCompletion.cpp

@@ -4360,7 +4360,7 @@ class CompletionOverrideLookup : public swift::VisibleDeclConsumer {
           continue;
         // FIXME: Also exclude the type alias that has already been specified.
         if (!Conformance->hasTypeWitness(ATD) ||
-            !ATD->getDefaultDefinitionLoc().isNull())
+            ATD->hasDefaultDefinitionType())
           continue;
         addTypeAlias(ATD,
           DeclVisibilityKind::MemberOfProtocolImplementedByCurrentNominal);

lib/Sema/TypeCheckProtocol.cpp

@@ -2616,7 +2616,7 @@ printRequirementStub(ValueDecl *Requirement, DeclContext *Adopter,
     }
   }
   if (auto MissingTypeWitness = dyn_cast<AssociatedTypeDecl>(Requirement)) {
-    if (!MissingTypeWitness->getDefaultDefinitionLoc().isNull()) {
+    if (MissingTypeWitness->hasDefaultDefinitionType()) {
       // For type witnesses with default definitions, we don't print the stub.
       return false;
     }

lib/Sema/TypeCheckProtocolInference.cpp

@@ -769,7 +769,7 @@ AssociatedTypeDecl *AssociatedTypeInference::findDefaultedAssociatedType(
                                              AssociatedTypeDecl *assocType) {
   // If this associated type has a default, we're done.
   tc.validateDecl(assocType);
-  if (!assocType->getDefaultDefinitionLoc().isNull())
+  if (assocType->hasDefaultDefinitionType())
     return assocType;
 
   // Look at overridden associated types.