[clang-tidy]: Add TagDecl into LastTagDeclRanges in UseUsingCheck only when it is a definition

[jcsxky]

Fix issue 67529, clang-tidy: modernize-use-using fails when type is implicitly forward declared
The problem is that using Lexer to get record declaration will lose the type information when its original type is pointer or reference. This patch fix this problem by skip adding the tag declaration when it's only a 'declaration' and not a 'definition'.

[llvmbot]

@llvm/pr-subscribers-clang-tidy

Changes

Fix issue 67529, clang-tidy: modernize-use-using fails when type is implicitly forward declared

---

Full diff: https://github.com/llvm/llvm-project/pull/67639.diff

2 Files Affected:

• (modified) clang-tools-extra/clang-tidy/modernize/UseUsingCheck.cpp (+2-1)
• (modified) clang-tools-extra/test/clang-tidy/checkers/modernize/use-using.cpp (+4)

diff --git a/clang-tools-extra/clang-tidy/modernize/UseUsingCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseUsingCheck.cpp
index 22dc9e21cab9d5a..e6293ed48bfddbb 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseUsingCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseUsingCheck.cpp
@@ -61,7 +61,8 @@ void UseUsingCheck::check(const MatchFinder::MatchResult &Result) {
     // before the typedef will be the nested one (PR#50990). Therefore, we also
     // keep track of the parent declaration, so that we can look up the last
     // TagDecl that is a sibling of the typedef in the AST.
-    LastTagDeclRanges[ParentDecl] = MatchedTagDecl->getSourceRange();
+    if (MatchedTagDecl->isThisDeclarationADefinition())
+      LastTagDeclRanges[ParentDecl] = MatchedTagDecl->getSourceRange();
     return;
   }
 
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-using.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-using.cpp
index f7db0af6434ac42..422abee11a71962 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-using.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-using.cpp
@@ -321,3 +321,7 @@ typedef bool (*ISSUE_65055_2)(int);
 // CHECK-MESSAGES: :[[@LINE-2]]:1: warning: use 'using' instead of 'typedef'
 // CHECK-FIXES: {{^}}using ISSUE_65055_1 = void (*)(int);{{$}}
 // CHECK-FIXES: {{^}}using ISSUE_65055_2 = bool (*)(int);{{$}}
+
+typedef class ISSUE_67529_1 *ISSUE_67529;
+// CHECK-MESSAGES: :[[@LINE-1]]:1: warning: use 'using' instead of 'typedef'
+// CHECK-FIXES: using ISSUE_67529 = class ISSUE_67529_1 *;

[PiotrZSL]

Release note entry would be welcome.

[jcsxky]

Release note entry would be welcome.

updated

[PiotrZSL]

Fix release notes, update change description (commit) to describe what was a problem. Mainly why isThisDeclarationADefinition is needed.
After that leave it open for few days before pushing, so someone else could also look into this and provide some comments if needed.

[jcsxky]

Fix release notes, update change description (commit) to describe what was a problem. Mainly why isThisDeclarationADefinition is needed. After that leave it open for few days before pushing, so someone else could also look into this and provide some comments if needed.

OK. Thanks for your review. Release notes and description have been updated.

[PiotrZSL]

LGTM