[clang-tidy] fix false positives with deducing this in readability-convert-member-functions-to-static check

Author: fubowen

clang-tools-extra/clang-tidy/readability/ConvertMemberFunctionsToStatic.cpp

@@ -62,6 +62,16 @@ AST_MATCHER(CXXMethodDecl, usesThis) {
       return false; // Stop traversal.
     }
 
+    bool VisitDeclRefExpr(const DeclRefExpr *E) {
+      if (const auto *PVD = dyn_cast_if_present<ParmVarDecl>(E->getDecl());
+          PVD && PVD->isExplicitObjectParameter()) {
+        Used = true;
+        return false; // Stop traversal.
+      }
+
+      return true;
+    }
+
     // If we enter a class declaration, don't traverse into it as any usages of
     // `this` will correspond to the nested class.
     bool TraverseCXXRecordDecl(CXXRecordDecl *RD) { return true; }

clang-tools-extra/docs/ReleaseNotes.rst

@@ -252,6 +252,10 @@ Changes in existing checks
   tolerating fix-it breaking compilation when functions is used as pointers
   to avoid matching usage of functions within the current compilation unit.
 
+- Improved :doc:`readability-convert-member-functions-to-static
+  <clang-tidy/checks/readability/convert-member-functions-to-static>` check by
+  fixing false positives on member functions with an explicit object parameter.
+
 - Improved :doc:`readability-math-missing-parentheses
   <clang-tidy/checks/readability/math-missing-parentheses>` check by fixing
   false negatives where math expressions are the operand of assignment operators

clang-tools-extra/test/clang-tidy/checkers/readability/convert-member-functions-to-static-deducing-this.cpp

@@ -0,0 +1,14 @@
+// RUN: %check_clang_tidy -std=c++23 %s readability-convert-member-functions-to-static %t
+
+namespace std{
+  class string {};
+  void println(const char *format, const std::string &str) {}
+}
+
+namespace PR141381 {
+struct Hello {
+  std::string str_;
+
+  void hello(this Hello &self) { std::println("Hello, {0}!", self.str_); }
+};
+}