[NFC] Sema: Refactor for recursive MemberTypeRepr representation

Author: AnthonyLatsis

include/swift/AST/TypeRepr.h

@@ -383,6 +383,8 @@ class DeclRefTypeRepr : public TypeRepr {
   /// arguments.
   bool hasGenericArgList() const;
 
+  unsigned getNumGenericArgs() const;
+
   ArrayRef<TypeRepr *> getGenericArgs() const;
 
   SourceRange getAngleBrackets() const;

lib/AST/TypeRepr.cpp

@@ -240,6 +240,15 @@ void DeclRefTypeRepr::setValue(TypeDecl *TD, DeclContext *DC) {
   getLastComponent()->setValue(TD, DC);
 }
 
+unsigned DeclRefTypeRepr::getNumGenericArgs() const {
+  auto *lastComp = const_cast<DeclRefTypeRepr *>(this)->getLastComponent();
+  if (auto *genericTR = dyn_cast<GenericIdentTypeRepr>(lastComp)) {
+    return genericTR->getNumGenericArgs();
+  }
+
+  return 0;
+}
+
 bool DeclRefTypeRepr::hasGenericArgList() const {
   return isa<GenericIdentTypeRepr>(
       const_cast<DeclRefTypeRepr *>(this)->getLastComponent());

lib/Sema/CSDiagnostics.cpp

@@ -6757,10 +6757,11 @@ void MissingGenericArgumentsFailure::emitGenericSignatureNote(
     auto diagnostic = emitDiagnosticAt(
         baseType->getLoc(), diag::unbound_generic_parameter_explicit_fix);
 
-    if (auto *genericTy = dyn_cast<GenericIdentTypeRepr>(baseType)) {
-      // If some of the eneric arguments have been specified, we need to
+    auto *declRefTR = dyn_cast<DeclRefTypeRepr>(baseType);
+    if (declRefTR && declRefTR->getAngleBrackets().isValid()) {
+      // If some of the generic arguments have been specified, we need to
       // replace existing signature with a new one.
-      diagnostic.fixItReplace(genericTy->getAngleBrackets(), paramsAsString);
+      diagnostic.fixItReplace(declRefTR->getAngleBrackets(), paramsAsString);
     } else {
       // Otherwise we can simply insert new generic signature.
       diagnostic.fixItInsertAfter(baseType->getEndLoc(), paramsAsString);
@@ -6770,7 +6771,7 @@ void MissingGenericArgumentsFailure::emitGenericSignatureNote(
 
 bool MissingGenericArgumentsFailure::findArgumentLocations(
     llvm::function_ref<void(TypeRepr *, GenericTypeParamType *)> callback) {
-  using Callback = llvm::function_ref<void(TypeRepr *, GenericTypeParamType *)>;
+  using Callback = decltype(callback);
 
   auto *const typeRepr = [this]() -> TypeRepr * {
     const auto anchor = getRawAnchor();
@@ -6799,14 +6800,14 @@ bool MissingGenericArgumentsFailure::findArgumentLocations(
     }
 
     PreWalkAction walkToTypeReprPre(TypeRepr *T) override {
-      if (Params.empty())
-        return Action::SkipNode();
+      if (allParamsAssigned())
+        return Action::Stop();
 
-      auto *ident = dyn_cast<IdentTypeRepr>(T);
-      if (!ident)
+      auto *declRefTR = dyn_cast<DeclRefTypeRepr>(T);
+      if (!declRefTR)
         return Action::Continue();
 
-      auto *decl = dyn_cast_or_null<GenericTypeDecl>(ident->getBoundDecl());
+      auto *decl = dyn_cast_or_null<GenericTypeDecl>(declRefTR->getBoundDecl());
       if (!decl)
         return Action::Continue();
 
@@ -6817,9 +6818,8 @@ bool MissingGenericArgumentsFailure::findArgumentLocations(
       // There could a situation like `S<S>()`, so we need to be
       // careful not to point at first `S` because it has all of
       // its generic parameters specified.
-      if (auto *generic = dyn_cast<GenericIdentTypeRepr>(ident)) {
-        if (paramList->size() == generic->getNumGenericArgs())
-          return Action::Continue();
+      if (paramList->size() == declRefTR->getNumGenericArgs()) {
+        return Action::Continue();
       }
 
       for (auto *candidate : paramList->getParams()) {
@@ -6829,7 +6829,7 @@ bool MissingGenericArgumentsFailure::findArgumentLocations(
             });
 
         if (result != Params.end()) {
-          Fn(ident, *result);
+          Fn(declRefTR, *result);
           Params.erase(result);
         }
       }

lib/Sema/TypeCheckAccess.cpp

@@ -361,8 +361,8 @@ static void highlightOffendingType(InFlightDiagnostic &diag,
   diag.highlight(complainRepr->getSourceRange());
   diag.flush();
 
-  if (auto ITR = dyn_cast<IdentTypeRepr>(complainRepr)) {
-    const ValueDecl *VD = ITR->getBoundDecl();
+  if (auto *declRefTR = dyn_cast<DeclRefTypeRepr>(complainRepr)) {
+    const ValueDecl *VD = declRefTR->getBoundDecl();
     VD->diagnose(diag::kind_declared_here, DescriptiveDeclKind::Type);
   }
 }
@@ -378,8 +378,8 @@ static void noteLimitingImport(ASTContext &ctx,
   assert(limitImport->accessLevel != AccessLevel::Public &&
          "a public import shouldn't limit the access level of a decl");
 
-  if (auto ITR = dyn_cast_or_null<IdentTypeRepr>(complainRepr)) {
-    ValueDecl *VD = ITR->getBoundDecl();
+  if (auto *declRefTR = dyn_cast_or_null<DeclRefTypeRepr>(complainRepr)) {
+    ValueDecl *VD = declRefTR->getBoundDecl();
     ctx.Diags.diagnose(limitImport->importLoc,
                        diag::decl_import_via_here,
                        VD,