Reland "[AST] Traverse the class type loc inside the member type loc.""

Summary: added a unittest which causes "TL.getClassTInfo" is null.

Reviewers: ilya-biryukov

Subscribers: mgorny, jkorous, arphaman, kadircet, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D71186

clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp

@@ -408,7 +408,7 @@ TEST(SemanticHighlighting, GetsCorrectTokens) {
     )cpp",
       R"cpp(
       template<typename $TemplateParameter[[T]],
-        void (T::*$TemplateParameter[[method]])(int)>
+        void ($TemplateParameter[[T]]::*$TemplateParameter[[method]])(int)>
       struct $Class[[G]] {
         void $Method[[foo]](
             $TemplateParameter[[T]] *$Parameter[[O]]) {

clang/include/clang/AST/RecursiveASTVisitor.h

@@ -1162,10 +1162,12 @@ DEF_TRAVERSE_TYPELOC(LValueReferenceType,
 DEF_TRAVERSE_TYPELOC(RValueReferenceType,
                      { TRY_TO(TraverseTypeLoc(TL.getPointeeLoc())); })
 
-// FIXME: location of base class?
 // We traverse this in the type case as well, but how is it not reached through
 // the pointee type?
 DEF_TRAVERSE_TYPELOC(MemberPointerType, {
+  if (auto *TSI = TL.getClassTInfo())
+    TRY_TO(TraverseTypeLoc(TSI->getTypeLoc()));
+  else
     TRY_TO(TraverseType(QualType(TL.getTypePtr()->getClass(), 0)));
   TRY_TO(TraverseTypeLoc(TL.getPointeeLoc()));
 })

clang/unittests/Tooling/CMakeLists.txt

@@ -42,6 +42,7 @@ add_clang_unittest(ToolingTests
   RecursiveASTVisitorTests/LambdaDefaultCapture.cpp
   RecursiveASTVisitorTests/LambdaExpr.cpp
   RecursiveASTVisitorTests/LambdaTemplateParams.cpp
+  RecursiveASTVisitorTests/MemberPointerTypeLoc.cpp
   RecursiveASTVisitorTests/NestedNameSpecifiers.cpp
   RecursiveASTVisitorTests/ParenExpr.cpp
   RecursiveASTVisitorTests/TemplateArgumentLocTraverser.cpp

clang/unittests/Tooling/RecursiveASTVisitorTests/MemberPointerTypeLoc.cpp

@@ -0,0 +1,55 @@
+//===- unittest/Tooling/RecursiveASTVisitorTests/MemberPointerTypeLoc.cpp -===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "TestVisitor.h"
+
+using namespace clang;
+
+namespace {
+
+class MemberPointerTypeLocVisitor
+    : public ExpectedLocationVisitor<MemberPointerTypeLocVisitor> {
+public:
+  bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
+    if (!TL)
+      return true;
+    Match(TL.getDecl()->getName(), TL.getNameLoc());
+    return true;
+  }
+  bool VisitRecordTypeLoc(RecordTypeLoc RTL) {
+    if (!RTL)
+      return true;
+    Match(RTL.getDecl()->getName(), RTL.getNameLoc());
+    return true;
+  }
+};
+
+TEST(RecursiveASTVisitor, VisitTypeLocInMemberPointerTypeLoc) {
+  MemberPointerTypeLocVisitor Visitor;
+  Visitor.ExpectMatch("Bar", 4, 36);
+  Visitor.ExpectMatch("T", 7, 23);
+  EXPECT_TRUE(Visitor.runOver(R"cpp(
+     class Bar { void func(int); };
+     class Foo {
+       void bind(const char*, void(Bar::*Foo)(int)) {}
+
+       template<typename T>
+       void test(void(T::*Foo)());
+     };
+  )cpp"));
+}
+
+TEST(RecursiveASTVisitor, NoCrash) {
+  MemberPointerTypeLocVisitor Visitor;
+  EXPECT_FALSE(Visitor.runOver(R"cpp(
+     // MemberPointerTypeLoc.getClassTInfo() is null.
+     class a(b(a::*)) class
+  )cpp"));
+}
+
+} // end anonymous namespace