Sema: Rework resolveTypeInContext()

Separate the "find the correct context" part from "substitute in the
base type" part. The former can go away completely after a bit of
refactoring.

Author: slavapestov

lib/Sema/GenericTypeResolver.h

@@ -47,7 +47,7 @@ class GenericTypeResolver {
   /// \returns The resolved generic type parameter type, which may be \c gp.
   virtual Type resolveGenericTypeParamType(GenericTypeParamType *gp) = 0;
 
-  /// Resolve a reference to a member within a dependent type.
+  /// Resolve a qualified reference to a type member within a dependent type.
   ///
   /// \param baseTy The base of the member access.
   /// \param baseRange The source range covering the base type.
@@ -60,7 +60,7 @@ class GenericTypeResolver {
                                           SourceRange baseRange,
                                           ComponentIdentTypeRepr *ref) = 0;
 
-  /// Resolve a reference to an associated type within the 'Self' type
+  /// Resolve an unqualified reference to an associated type of the 'Self' type
   /// of a protocol.
   ///
   /// \param selfTy The base of the member access.
@@ -69,21 +69,15 @@ class GenericTypeResolver {
   /// \returns A type that refers to the dependent member type, or an error
   /// type if such a reference is ill-formed.
   virtual Type resolveSelfAssociatedType(Type selfTy,
-                                         DeclContext *DC,
                                          AssociatedTypeDecl *assocType) = 0;
 
-  /// Retrieve the type when referring to the given context.
+  /// Resolve the self type within the given context.
   ///
   /// \param dc A context in which type checking occurs, which must be a type
   /// context (i.e., nominal type or extension thereof).
   ///
-  /// \param wantSelf Do we want the type of the context itself (the
-  /// existential type, for protocols) or the type of 'self' inside the
-  /// context (the 'Self' generic parameter, for protocols). Has no effect
-  /// for concrete types.
-  ///
   /// \returns the type of context.
-  virtual Type resolveTypeOfContext(DeclContext *dc, bool wantSelf=false) = 0;
+  virtual Type resolveTypeOfContext(DeclContext *dc) = 0;
 
   /// Retrieve the type when referring to the given type declaration within
   /// its context.
@@ -116,10 +110,9 @@ class DependentGenericTypeResolver : public GenericTypeResolver {
                                           ComponentIdentTypeRepr *ref);
 
   virtual Type resolveSelfAssociatedType(Type selfTy,
-                                         DeclContext *DC,
                                          AssociatedTypeDecl *assocType);
 
-  virtual Type resolveTypeOfContext(DeclContext *dc, bool wantSelf=false);
+  virtual Type resolveTypeOfContext(DeclContext *dc);
 
   virtual Type resolveTypeOfDecl(TypeDecl *decl);
 
@@ -149,10 +142,9 @@ class GenericTypeToArchetypeResolver : public GenericTypeResolver {
                                           ComponentIdentTypeRepr *ref);
 
   virtual Type resolveSelfAssociatedType(Type selfTy,
-                                         DeclContext *DC,
                                          AssociatedTypeDecl *assocType);
 
-  virtual Type resolveTypeOfContext(DeclContext *dc, bool wantSelf=false);
+  virtual Type resolveTypeOfContext(DeclContext *dc);
 
   virtual Type resolveTypeOfDecl(TypeDecl *decl);
 
@@ -182,10 +174,9 @@ class CompleteGenericTypeResolver : public GenericTypeResolver {
                                           ComponentIdentTypeRepr *ref);
 
   virtual Type resolveSelfAssociatedType(Type selfTy,
-                                         DeclContext *DC,
                                          AssociatedTypeDecl *assocType);
 
-  virtual Type resolveTypeOfContext(DeclContext *dc, bool wantSelf=false);
+  virtual Type resolveTypeOfContext(DeclContext *dc);
 
   virtual Type resolveTypeOfDecl(TypeDecl *decl);
 

lib/Sema/TypeCheckGeneric.cpp

@@ -50,9 +50,7 @@ Type DependentGenericTypeResolver::resolveDependentMemberType(
 }
 
 Type DependentGenericTypeResolver::resolveSelfAssociatedType(
-       Type selfTy,
-       DeclContext *DC,
-       AssociatedTypeDecl *assocType) {
+       Type selfTy, AssociatedTypeDecl *assocType) {
   auto archetype = Builder.resolveArchetype(selfTy);
   assert(archetype && "Bad generic context nesting?");
 
@@ -61,15 +59,8 @@ Type DependentGenericTypeResolver::resolveSelfAssociatedType(
            ->getDependentType(/*FIXME: */{ }, /*allowUnresolved=*/true);
 }
 
-static Type getTypeOfContext(DeclContext *dc, bool wantSelf) {
-  if (wantSelf)
-    return dc->getSelfInterfaceType();
-  return dc->getDeclaredInterfaceType();
-}
-
-Type DependentGenericTypeResolver::resolveTypeOfContext(DeclContext *dc,
-                                                        bool wantSelf) {
-  return getTypeOfContext(dc, wantSelf);
+Type DependentGenericTypeResolver::resolveTypeOfContext(DeclContext *dc) {
+  return dc->getSelfInterfaceType();
 }
 
 Type DependentGenericTypeResolver::resolveTypeOfDecl(TypeDecl *decl) {
@@ -106,21 +97,20 @@ Type GenericTypeToArchetypeResolver::resolveDependentMemberType(
 }
 
 Type GenericTypeToArchetypeResolver::resolveSelfAssociatedType(
-       Type selfTy,
-       DeclContext *DC,
-       AssociatedTypeDecl *assocType) {
+       Type selfTy, AssociatedTypeDecl *assocType) {
   llvm_unreachable("Dependent type after archetype substitution");  
 }
 
-Type GenericTypeToArchetypeResolver::resolveTypeOfContext(DeclContext *dc,
-                                                          bool wantSelf) {
+Type GenericTypeToArchetypeResolver::resolveTypeOfContext(DeclContext *dc) {
   // FIXME: Fallback case.
-  if (dc->isGenericContext() && !dc->isValidGenericContext())
-    return getTypeOfContext(dc, wantSelf);
+  if (!isa<ExtensionDecl>(dc) &&
+      dc->isGenericContext() &&
+      !dc->isValidGenericContext())
+    return dc->getSelfInterfaceType();
 
   return ArchetypeBuilder::mapTypeIntoContext(
       dc->getParentModule(), GenericEnv,
-      getTypeOfContext(dc, wantSelf));
+      dc->getSelfInterfaceType());
 }
 
 Type GenericTypeToArchetypeResolver::resolveTypeOfDecl(TypeDecl *decl) {
@@ -242,17 +232,15 @@ Type CompleteGenericTypeResolver::resolveDependentMemberType(
   return ErrorType::get(TC.Context);
 }
 
-Type CompleteGenericTypeResolver::resolveSelfAssociatedType(Type selfTy,
-       DeclContext *DC,
-       AssociatedTypeDecl *assocType) {
+Type CompleteGenericTypeResolver::resolveSelfAssociatedType(
+       Type selfTy, AssociatedTypeDecl *assocType) {
   return Builder.resolveArchetype(selfTy)->getRepresentative()
            ->getNestedType(assocType->getName(), Builder)
            ->getDependentType(/*FIXME: */{ }, /*allowUnresolved=*/false);
 }
 
-Type CompleteGenericTypeResolver::resolveTypeOfContext(DeclContext *dc,
-                                                       bool wantSelf) {
-  return getTypeOfContext(dc, wantSelf);
+Type CompleteGenericTypeResolver::resolveTypeOfContext(DeclContext *dc) {
+  return dc->getSelfInterfaceType();
 }
 
 Type CompleteGenericTypeResolver::resolveTypeOfDecl(TypeDecl *decl) {