[clang][CodeComplete] Use HeuristicResolver in getAsRecordDecl() (#130473)

Fixes #130468

Author: HighCommander4

clang/include/clang/Sema/HeuristicResolver.h

@@ -81,6 +81,18 @@ class HeuristicResolver {
   // could look up the name appearing on the RHS.
   const QualType getPointeeType(QualType T) const;
 
+  // Heuristically resolve a possibly-dependent type `T` to a TagDecl
+  // in which a member's name can be looked up.
+  TagDecl *resolveTypeToTagDecl(QualType T) const;
+
+  // Simplify the type `Type`.
+  // `E` is the expression whose type `Type` is, if known. This sometimes
+  // contains information relevant to the type that's not stored in `Type`
+  // itself.
+  // If `UnwrapPointer` is true, exactly only pointer type will be unwrapped
+  // during simplification, and the operation fails if no pointer type is found.
+  QualType simplifyType(QualType Type, const Expr *E, bool UnwrapPointer);
+
 private:
   ASTContext &Ctx;
 };

clang/include/clang/Sema/Sema.h

@@ -291,7 +291,8 @@ class FileNullabilityMap {
 /// parameter. This avoids updating the type on hot paths in the parser.
 class PreferredTypeBuilder {
 public:
-  PreferredTypeBuilder(bool Enabled) : Enabled(Enabled) {}
+  PreferredTypeBuilder(ASTContext *Ctx, bool Enabled)
+      : Ctx(Ctx), Enabled(Enabled) {}
 
   void enterCondition(Sema &S, SourceLocation Tok);
   void enterReturn(Sema &S, SourceLocation Tok);
@@ -337,6 +338,7 @@ class PreferredTypeBuilder {
   }
 
 private:
+  ASTContext *Ctx;
   bool Enabled;
   /// Start position of a token for which we store expected type.
   SourceLocation ExpectedLoc;

clang/lib/Parse/Parser.cpp

@@ -54,8 +54,9 @@ IdentifierInfo *Parser::getSEHExceptKeyword() {
 }
 
 Parser::Parser(Preprocessor &pp, Sema &actions, bool skipFunctionBodies)
-    : PP(pp), PreferredType(pp.isCodeCompletionEnabled()), Actions(actions),
-      Diags(PP.getDiagnostics()), StackHandler(Diags),
+    : PP(pp),
+      PreferredType(&actions.getASTContext(), pp.isCodeCompletionEnabled()),
+      Actions(actions), Diags(PP.getDiagnostics()), StackHandler(Diags),
       GreaterThanIsOperator(true), ColonIsSacred(false),
       InMessageExpression(false), TemplateParameterDepth(0),
       ParsingInObjCContainer(false) {

clang/lib/Sema/HeuristicResolver.cpp

@@ -48,6 +48,8 @@ class HeuristicResolverImpl {
   std::vector<const NamedDecl *>
   lookupDependentName(CXXRecordDecl *RD, DeclarationName Name,
                       llvm::function_ref<bool(const NamedDecl *ND)> Filter);
+  TagDecl *resolveTypeToTagDecl(QualType T);
+  QualType simplifyType(QualType Type, const Expr *E, bool UnwrapPointer);
 
 private:
   ASTContext &Ctx;
@@ -73,20 +75,6 @@ class HeuristicResolverImpl {
   QualType resolveExprToType(const Expr *E);
   std::vector<const NamedDecl *> resolveExprToDecls(const Expr *E);
 
-  // Helper function for HeuristicResolver::resolveDependentMember()
-  // which takes a possibly-dependent type `T` and heuristically
-  // resolves it to a TagDecl in which we can try name lookup.
-  TagDecl *resolveTypeToTagDecl(const Type *T);
-
-  // Helper function for simplifying a type.
-  // `Type` is the type to simplify.
-  // `E` is the expression whose type `Type` is, if known. This sometimes
-  // contains information relevant to the type that's not stored in `Type`
-  // itself.
-  // If `UnwrapPointer` is true, exactly only pointer type will be unwrapped
-  // during simplification, and the operation fails if no pointer type is found.
-  QualType simplifyType(QualType Type, const Expr *E, bool UnwrapPointer);
-
   bool findOrdinaryMemberInDependentClasses(const CXXBaseSpecifier *Specifier,
                                             CXXBasePath &Path,
                                             DeclarationName Name);
@@ -133,8 +121,10 @@ TemplateName getReferencedTemplateName(const Type *T) {
 // Helper function for HeuristicResolver::resolveDependentMember()
 // which takes a possibly-dependent type `T` and heuristically
 // resolves it to a CXXRecordDecl in which we can try name lookup.
-TagDecl *HeuristicResolverImpl::resolveTypeToTagDecl(const Type *T) {
-  assert(T);
+TagDecl *HeuristicResolverImpl::resolveTypeToTagDecl(QualType QT) {
+  const Type *T = QT.getTypePtrOrNull();
+  if (!T)
+    return nullptr;
 
   // Unwrap type sugar such as type aliases.
   T = T->getCanonicalTypeInternal().getTypePtr();
@@ -148,7 +138,15 @@ TagDecl *HeuristicResolverImpl::resolveTypeToTagDecl(const Type *T) {
   }
 
   if (auto *TT = T->getAs<TagType>()) {
-    return TT->getDecl();
+    TagDecl *TD = TT->getDecl();
+    // Template might not be instantiated yet, fall back to primary template
+    // in such cases.
+    if (const auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(TD)) {
+      if (CTSD->getTemplateSpecializationKind() == TSK_Undeclared) {
+        return CTSD->getSpecializedTemplate()->getTemplatedDecl();
+      }
+    }
+    return TD;
   }
 
   if (const auto *ICNT = T->getAs<InjectedClassNameType>())
@@ -330,8 +328,7 @@ HeuristicResolverImpl::resolveTypeOfCallExpr(const CallExpr *CE) {
   if (const auto *FnTypePtr = CalleeType->getAs<PointerType>())
     CalleeType = FnTypePtr->getPointeeType();
   if (const FunctionType *FnType = CalleeType->getAs<FunctionType>()) {
-    if (const auto *D =
-            resolveTypeToTagDecl(FnType->getReturnType().getTypePtr())) {
+    if (const auto *D = resolveTypeToTagDecl(FnType->getReturnType())) {
       return {D};
     }
   }
@@ -442,7 +439,7 @@ bool findOrdinaryMember(const CXXRecordDecl *RD, CXXBasePath &Path,
 bool HeuristicResolverImpl::findOrdinaryMemberInDependentClasses(
     const CXXBaseSpecifier *Specifier, CXXBasePath &Path,
     DeclarationName Name) {
-  TagDecl *TD = resolveTypeToTagDecl(Specifier->getType().getTypePtr());
+  TagDecl *TD = resolveTypeToTagDecl(Specifier->getType());
   if (const auto *RD = dyn_cast_if_present<CXXRecordDecl>(TD)) {
     return findOrdinaryMember(RD, Path, Name);
   }
@@ -485,10 +482,7 @@ std::vector<const NamedDecl *> HeuristicResolverImpl::lookupDependentName(
 std::vector<const NamedDecl *> HeuristicResolverImpl::resolveDependentMember(
     QualType QT, DeclarationName Name,
     llvm::function_ref<bool(const NamedDecl *ND)> Filter) {
-  const Type *T = QT.getTypePtrOrNull();
-  if (!T)
-    return {};
-  TagDecl *TD = resolveTypeToTagDecl(T);
+  TagDecl *TD = resolveTypeToTagDecl(QT);
   if (!TD)
     return {};
   if (auto *ED = dyn_cast<EnumDecl>(TD)) {
@@ -555,5 +549,12 @@ std::vector<const NamedDecl *> HeuristicResolver::lookupDependentName(
 const QualType HeuristicResolver::getPointeeType(QualType T) const {
   return HeuristicResolverImpl(Ctx).getPointeeType(T);
 }
+TagDecl *HeuristicResolver::resolveTypeToTagDecl(QualType T) const {
+  return HeuristicResolverImpl(Ctx).resolveTypeToTagDecl(T);
+}
+QualType HeuristicResolver::simplifyType(QualType Type, const Expr *E,
+                                         bool UnwrapPointer) {
+  return HeuristicResolverImpl(Ctx).simplifyType(Type, E, UnwrapPointer);
+}
 
 } // namespace clang

clang/lib/Sema/SemaCodeComplete.cpp

@@ -436,15 +436,17 @@ void PreferredTypeBuilder::enterVariableInit(SourceLocation Tok, Decl *D) {
   ExpectedLoc = Tok;
 }
 
-static QualType getDesignatedType(QualType BaseType, const Designation &Desig);
+static QualType getDesignatedType(QualType BaseType, const Designation &Desig,
+                                  HeuristicResolver &Resolver);
 
 void PreferredTypeBuilder::enterDesignatedInitializer(SourceLocation Tok,
                                                       QualType BaseType,
                                                       const Designation &D) {
   if (!Enabled)
     return;
   ComputeType = nullptr;
-  Type = getDesignatedType(BaseType, D);
+  HeuristicResolver Resolver(*Ctx);
+  Type = getDesignatedType(BaseType, D, Resolver);
   ExpectedLoc = Tok;
 }
 
@@ -5346,27 +5348,11 @@ AddRecordMembersCompletionResults(Sema &SemaRef, ResultBuilder &Results,
 // Returns the RecordDecl inside the BaseType, falling back to primary template
 // in case of specializations. Since we might not have a decl for the
 // instantiation/specialization yet, e.g. dependent code.
-static RecordDecl *getAsRecordDecl(QualType BaseType) {
-  BaseType = BaseType.getNonReferenceType();
-  if (auto *RD = BaseType->getAsRecordDecl()) {
-    if (const auto *CTSD =
-            llvm::dyn_cast<ClassTemplateSpecializationDecl>(RD)) {
-      // Template might not be instantiated yet, fall back to primary template
-      // in such cases.
-      if (CTSD->getTemplateSpecializationKind() == TSK_Undeclared)
-        RD = CTSD->getSpecializedTemplate()->getTemplatedDecl();
-    }
-    return RD;
-  }
-
-  if (const auto *TST = BaseType->getAs<TemplateSpecializationType>()) {
-    if (const auto *TD = dyn_cast_or_null<ClassTemplateDecl>(
-            TST->getTemplateName().getAsTemplateDecl())) {
-      return TD->getTemplatedDecl();
-    }
-  }
-
-  return nullptr;
+static RecordDecl *getAsRecordDecl(QualType BaseType,
+                                   HeuristicResolver &Resolver) {
+  BaseType = Resolver.simplifyType(BaseType, nullptr, /*UnwrapPointer=*/false);
+  return dyn_cast_if_present<RecordDecl>(
+      Resolver.resolveTypeToTagDecl(BaseType));
 }
 
 namespace {
@@ -5912,7 +5898,7 @@ void SemaCodeCompletion::CodeCompleteMemberReferenceExpr(
       }
     }
 
-    if (RecordDecl *RD = getAsRecordDecl(BaseType)) {
+    if (RecordDecl *RD = getAsRecordDecl(BaseType, Resolver)) {
       AddRecordMembersCompletionResults(SemaRef, Results, S, BaseType, BaseKind,
                                         RD, std::move(AccessOpFixIt));
     } else if (const auto *TTPT =
@@ -6675,7 +6661,8 @@ QualType SemaCodeCompletion::ProduceTemplateArgumentSignatureHelp(
                               /*Braced=*/false);
 }
 
-static QualType getDesignatedType(QualType BaseType, const Designation &Desig) {
+static QualType getDesignatedType(QualType BaseType, const Designation &Desig,
+                                  HeuristicResolver &Resolver) {
   for (unsigned I = 0; I < Desig.getNumDesignators(); ++I) {
     if (BaseType.isNull())
       break;
@@ -6686,7 +6673,7 @@ static QualType getDesignatedType(QualType BaseType, const Designation &Desig) {
         NextType = BaseType->getAsArrayTypeUnsafe()->getElementType();
     } else {
       assert(D.isFieldDesignator());
-      auto *RD = getAsRecordDecl(BaseType);
+      auto *RD = getAsRecordDecl(BaseType, Resolver);
       if (RD && RD->isCompleteDefinition()) {
         for (const auto *Member : RD->lookup(D.getFieldDecl()))
           if (const FieldDecl *FD = llvm::dyn_cast<FieldDecl>(Member)) {
@@ -6702,10 +6689,10 @@ static QualType getDesignatedType(QualType BaseType, const Designation &Desig) {
 
 void SemaCodeCompletion::CodeCompleteDesignator(
     QualType BaseType, llvm::ArrayRef<Expr *> InitExprs, const Designation &D) {
-  BaseType = getDesignatedType(BaseType, D);
+  BaseType = getDesignatedType(BaseType, D, Resolver);
   if (BaseType.isNull())
     return;
-  const auto *RD = getAsRecordDecl(BaseType);
+  const auto *RD = getAsRecordDecl(BaseType, Resolver);
   if (!RD || RD->fields().empty())
     return;
 

clang/test/CodeCompletion/member-access.cpp

@@ -431,7 +431,9 @@ using Alias = S<T>;
 template <typename T>
 void f(Alias<T> s) {
   s.a.b;
-  // RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:433:7 %s -o - | FileCheck -check-prefix=CHECK-TEMPLATE-ALIAS %s
-  // CHECK-TEMPLATE-ALIAS: [#int#]b
+  // RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:433:5 %s -o - | FileCheck -check-prefix=CHECK-TEMPLATE-ALIAS %s
+  // CHECK-TEMPLATE-ALIAS: [#A#]a
+  // RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:433:7 %s -o - | FileCheck -check-prefix=CHECK-TEMPLATE-ALIAS-NESTED %s
+  // CHECK-TEMPLATE-ALIAS-NESTED: [#int#]b
 }
 }