[clang] Add missing type source info of decltype specifier in destructor call to AST (#197680)

The type source info will be stored in `MemberExpr::MemberDNLoc`.

This patch fixes the underlying issue of #195788.

clang-tools-extra/clangd/Selection.cpp

@@ -895,19 +895,13 @@ private:
     // rather than the TypeLoc nested inside it.
     // We still traverse the TypeLoc, because it may contain other targeted
     // things like the T in ~Foo<T>().
-    // FIXME: Investigate if getNamedTypeInfo() can still return null for
-    // invalid cases, and drop these checks when it never returns null.
-    if (const auto *CDD = N.get<CXXDestructorDecl>()) {
-      if (auto *TypeInfo = CDD->getNameInfo().getNamedTypeInfo())
-        return TypeInfo->getTypeLoc().getBeginLoc();
-    }
+    if (const auto *CDD = N.get<CXXDestructorDecl>())
+      return CDD->getNameInfo().getNamedTypeInfo()->getTypeLoc().getBeginLoc();
     if (const auto *ME = N.get<MemberExpr>()) {
       auto NameInfo = ME->getMemberNameInfo();
       if (NameInfo.getName().getNameKind() ==
-          DeclarationName::CXXDestructorName) {
-        if (auto *TypeInfo = NameInfo.getNamedTypeInfo())
-          return TypeInfo->getTypeLoc().getBeginLoc();
-      }
+          DeclarationName::CXXDestructorName)
+        return NameInfo.getNamedTypeInfo()->getTypeLoc().getBeginLoc();
     }
 
     return SourceRange();

clang-tools-extra/clangd/SemanticHighlighting.cpp

@@ -789,13 +789,12 @@ public:
   }
 
   bool VisitCXXDestructorDecl(CXXDestructorDecl *D) {
-    if (auto *TI = D->getNameInfo().getNamedTypeInfo()) {
-      SourceLocation Loc = TI->getTypeLoc().getBeginLoc();
-      H.addExtraModifier(Loc, HighlightingModifier::ConstructorOrDestructor);
-      H.addExtraModifier(Loc, HighlightingModifier::Declaration);
-      if (D->isThisDeclarationADefinition())
-        H.addExtraModifier(Loc, HighlightingModifier::Definition);
-    }
+    SourceLocation Loc =
+        D->getNameInfo().getNamedTypeInfo()->getTypeLoc().getBeginLoc();
+    H.addExtraModifier(Loc, HighlightingModifier::ConstructorOrDestructor);
+    H.addExtraModifier(Loc, HighlightingModifier::Declaration);
+    if (D->isThisDeclarationADefinition())
+      H.addExtraModifier(Loc, HighlightingModifier::Definition);
     return true;
   }
 
@@ -804,12 +803,12 @@ public:
     // `(foo.*pointer_to_member_fun)(arg);`
     if (auto *D = CE->getMethodDecl()) {
       if (isa<CXXDestructorDecl>(D)) {
-        if (auto *ME = dyn_cast<MemberExpr>(CE->getCallee())) {
-          if (auto *TI = ME->getMemberNameInfo().getNamedTypeInfo()) {
-            H.addExtraModifier(TI->getTypeLoc().getBeginLoc(),
-                               HighlightingModifier::ConstructorOrDestructor);
-          }
-        }
+        if (auto *ME = dyn_cast<MemberExpr>(CE->getCallee()))
+          H.addExtraModifier(ME->getMemberNameInfo()
+                                 .getNamedTypeInfo()
+                                 ->getTypeLoc()
+                                 .getBeginLoc(),
+                             HighlightingModifier::ConstructorOrDestructor);
       } else if (D->isOverloadedOperator()) {
         if (auto *ME = dyn_cast<MemberExpr>(CE->getCallee()))
           H.addToken(

clang/docs/ReleaseNotes.rst

@@ -687,6 +687,7 @@ Bug Fixes to AST Handling
 - Fixed a crash when parsing Doxygen ``@param`` commands attached to invalid declarations or non-function entities. (#GH182737)
 - Fixed the SourceLocation and SourceRange of reversed rewritten CXXOperatorCallExpr. (#GH192467)
 - Fixed a assertion when ``__block`` is used on global variables in C mode. (#GH183974)
+- Added missing AST nodes representing the ``decltype`` specifiers in destructor call to AST.
 
 Miscellaneous Bug Fixes
 ^^^^^^^^^^^^^^^^^^^^^^^

clang/include/clang/AST/DeclarationName.h

@@ -830,8 +830,8 @@ public:
   const DeclarationNameLoc &getInfo() const { return LocInfo; }
   void setInfo(const DeclarationNameLoc &Info) { LocInfo = Info; }
 
-  /// getNamedTypeInfo - Returns the source type info associated to
-  /// the name. Assumes it is a constructor, destructor or conversion.
+  /// @return The type source info associated to the name if it is a
+  /// constructor, destructor or conversion function, `nullptr` otherwise.
   TypeSourceInfo *getNamedTypeInfo() const {
     if (Name.getNameKind() != DeclarationName::CXXConstructorName &&
         Name.getNameKind() != DeclarationName::CXXDestructorName &&

clang/lib/Sema/SemaExprCXX.cpp

@@ -479,7 +479,11 @@ ParsedType Sema::getDestructorTypeForDecltype(const DeclSpec &DS,
     return nullptr;
   }
 
-  return ParsedType::make(T);
+  TypeLocBuilder TLB;
+  DecltypeTypeLoc DecltypeTL = TLB.push<DecltypeTypeLoc>(T);
+  DecltypeTL.setDecltypeLoc(DS.getTypeSpecTypeLoc());
+  DecltypeTL.setRParenLoc(DS.getTypeofParensRange().getEnd());
+  return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
 }
 
 bool Sema::checkLiteralOperatorId(const CXXScopeSpec &SS,

clang/test/AST/ast-dump-expr-json.cpp

@@ -3208,8 +3208,8 @@ void TestNonADLCall3() {
 // CHECK-NEXT:          "tokLen": 1
 // CHECK-NEXT:         },
 // CHECK-NEXT:         "end": {
-// CHECK-NEXT:          "offset": 1693,
-// CHECK-NEXT:          "col": 5,
+// CHECK-NEXT:          "offset": 1704,
+// CHECK-NEXT:          "col": 16,
 // CHECK-NEXT:          "tokLen": 1
 // CHECK-NEXT:         }
 // CHECK-NEXT:        },

clang/test/AST/ast-dump-expr.cpp

@@ -216,7 +216,7 @@ void PostfixExpressions(S a, S *p, U<int> *r) {
   // the construct above.
   a.~decltype(a)();
   // CHECK: CXXMemberCallExpr 0x{{[^ ]*}} <line:[[@LINE-1]]:3, col:18> 'void'
-  // CHECK-NEXT: MemberExpr 0x{{[^ ]*}} <col:3, col:5> '<bound member function type>' .~S 0x{{[^ ]*}}
+  // CHECK-NEXT: MemberExpr 0x{{[^ ]*}} <col:3, col:16> '<bound member function type>' .~S 0x{{[^ ]*}}
   // CHECK-NEXT: DeclRefExpr 0x{{[^ ]*}} <col:3> 'S' lvalue ParmVar 0x{{[^ ]*}} 'a' 'S'
 
   p->::S::~S();

clang/unittests/Tooling/Syntax/BuildTreeTest.cpp

@@ -671,10 +671,6 @@ TEST_P(BuildSyntaxTreeTest, UnqualifiedId_DecltypeDestructor) {
       R"cpp(
 struct X { };
 void test(X x) {
-  // FIXME: Make `decltype(x)` a child of `MemberExpression`. It is currently
-  // not because `Expr::getSourceRange()` returns the range of `x.~` for the
-  // `MemberExpr` instead of the expected `x.~decltype(x)`, this is a bug in
-  // clang.
   [[x.~decltype(x)()]];
 }
 )cpp",
@@ -687,12 +683,14 @@ CallExpression Expression
 | |-'.' AccessToken
 | `-IdExpression Member
 |   `-UnqualifiedId UnqualifiedId
-|     `-'~'
-|-'decltype'
-|-'('
-|-'x'
-|-')'
-|-'('
+|     |-'~'
+|     |-'decltype'
+|     |-'('
+|     |-IdExpression
+|     | `-UnqualifiedId UnqualifiedId
+|     |   `-'x'
+|     `-')'
+|-'(' OpenParen
 `-')' CloseParen
 )txt"}));
 }