[clang-tools-extra] 2712d71 - [clang-tidy] Fix assert failure in modernize-use-std-format when args are in macros (#176684)

[via cfe-commits]

Author: mitchell
Date: 2026-01-21T13:16:51+08:00
New Revision: 2712d71cc3d8a4d69fd9eef001768f350549ec47

URL: https://github.com/llvm/llvm-project/commit/2712d71cc3d8a4d69fd9eef001768f350549ec47
DIFF: https://github.com/llvm/llvm-project/commit/2712d71cc3d8a4d69fd9eef001768f350549ec47.diff

LOG: [clang-tidy] Fix assert failure in modernize-use-std-format when args are in macros (#176684)

Part of [#175183](https://github.com/llvm/llvm-project/issues/175183)

Added: 
    

Modified: 
    clang-tools-extra/clang-tidy/utils/FormatStringConverter.cpp
    clang-tools-extra/docs/ReleaseNotes.rst
    clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-format.cpp

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/clang-tidy/utils/FormatStringConverter.cpp b/clang-tools-extra/clang-tidy/utils/FormatStringConverter.cpp
index cbf852ea7afc3..4feeaa18740d7 100644
--- a/clang-tools-extra/clang-tidy/utils/FormatStringConverter.cpp
+++ b/clang-tools-extra/clang-tidy/utils/FormatStringConverter.cpp
@@ -800,10 +800,12 @@ void FormatStringConverter::applyFixes(DiagnosticBuilder &Diag,
   }
 
   for (const auto &[ArgIndex, Replacement] : ArgFixes) {
-    const SourceLocation AfterOtherSide =
+    const std::optional<Token> NextToken =
         utils::lexer::findNextTokenSkippingComments(Args[ArgIndex]->getEndLoc(),
-                                                    SM, LangOpts)
-            ->getLocation();
+                                                    SM, LangOpts);
+    if (!NextToken)
+      continue;
+    const SourceLocation AfterOtherSide = NextToken->getLocation();
 
     Diag << FixItHint::CreateInsertion(Args[ArgIndex]->getBeginLoc(),
                                        Replacement, true)

diff  --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 52a893ae62494..cfd7d277db29c 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -114,6 +114,10 @@ Changes in existing checks
   - Added support for analyzing function parameters with the `AnalyzeParameters`
     option.
 
+- Improved :doc:`modernize-use-std-format
+  <clang-tidy/checks/modernize/use-std-format>` check by fixing a crash
+  when an argument is part of a macro expansion.
+
 - Improved :doc:`modernize-use-using
   <clang-tidy/checks/modernize/use-using>` check by avoiding the generation
   of invalid code for function types with redundant parentheses.

diff  --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-format.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-format.cpp
index 6a6cb9857fff1..30a8c54f9f125 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-format.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-format.cpp
@@ -26,6 +26,8 @@ struct iterator {
   T &operator*();
 };
 
+enum E { E1 };
+
 std::string StrFormat_simple() {
   return absl::StrFormat("Hello");
   // CHECK-MESSAGES: [[@LINE-1]]:10: warning: use 'std::format' instead of 'StrFormat' [modernize-use-std-format]
@@ -177,4 +179,10 @@ void StrFormat_macros() {
 #define SURROUND_FORMAT(x) "!" x
   auto s15 = absl::StrFormat(SURROUND_FORMAT("Hello %d"), 4443);
   // CHECK-MESSAGES: [[@LINE-1]]:14: warning: unable to use 'std::format' instead of 'StrFormat' because format string contains unreplaceable macro 'SURROUND_FORMAT' [modernize-use-std-format]
+
+  // Ensure that we don't crash if the call is within a macro.
+#define WRAP_IN_MACRO(x) x
+  WRAP_IN_MACRO(absl::StrFormat("Hello %d", E1));
+  // CHECK-MESSAGES: [[@LINE-1]]:17: warning: use 'std::format' instead of 'StrFormat' [modernize-use-std-format]
+  // CHECK-FIXES: WRAP_IN_MACRO(std::format("Hello {}", E1));
 }