From e67f2cc3fc38cec2041cfb197ac4688ed3d16e7e Mon Sep 17 00:00:00 2001
From: Edwin Vane <revane@google.com>
Date: Tue, 21 May 2024 14:51:50 -0400
Subject: [PATCH] [clang-tidy] Rename out-of-line function definitions (#91954)

Member function templates defined out-of-line were resulting in
conflicting naming failures with overlapping usage sets. With this
change, out-of-line definitions are treated as a usage of the failure
which is the inline declaration.
---
 .../utils/RenamerClangTidyCheck.cpp           |  3 ++
 clang-tools-extra/docs/ReleaseNotes.rst       |  3 +-
 .../identifier-naming-outofline.cpp           | 30 +++++++++++++++++++
 3 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming-outofline.cpp

diff --git a/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp b/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
index e811f5519de2..88e4886cd0df 100644
--- a/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
+++ b/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
@@ -123,6 +123,9 @@ static const NamedDecl *getFailureForNamedDecl(const NamedDecl *ND) {
   if (const auto *Method = dyn_cast<CXXMethodDecl>(ND)) {
     if (const CXXMethodDecl *Overridden = getOverrideMethod(Method))
       Canonical = cast<NamedDecl>(Overridden->getCanonicalDecl());
+    else if (const FunctionTemplateDecl *Primary = Method->getPrimaryTemplate())
+      if (const FunctionDecl *TemplatedDecl = Primary->getTemplatedDecl())
+        Canonical = cast<NamedDecl>(TemplatedDecl->getCanonicalDecl());
 
     if (Canonical != ND)
       return Canonical;
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 6a9892bada91..741abc0a199a 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -375,7 +375,8 @@ Changes in existing checks
   <clang-tidy/checks/readability/identifier-naming>` check in `GetConfigPerFile`
   mode by resolving symbolic links to header files. Fixed handling of Hungarian
   Prefix when configured to `LowerCase`. Added support for renaming designated
-  initializers. Added support for renaming macro arguments.
+  initializers. Added support for renaming macro arguments. Fixed renaming
+  conflicts arising from out-of-line member function template definitions.
 
 - Improved :doc:`readability-implicit-bool-conversion
   <clang-tidy/checks/readability/implicit-bool-conversion>` check to provide
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming-outofline.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming-outofline.cpp
new file mode 100644
index 000000000000..f807875e2769
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming-outofline.cpp
@@ -0,0 +1,30 @@
+// RUN: %check_clang_tidy %s readability-identifier-naming %t -std=c++20 \
+// RUN:   --config='{CheckOptions: { \
+// RUN:     readability-identifier-naming.MethodCase: CamelCase, \
+// RUN:  }}'
+
+namespace SomeNamespace {
+namespace Inner {
+
+class SomeClass {
+public:
+    template <typename T>
+    int someMethod();
+// CHECK-MESSAGES: :[[@LINE-1]]:9: warning: invalid case style for method 'someMethod' [readability-identifier-naming]
+// CHECK-FIXES: {{^}}    int SomeMethod();
+};
+template <typename T>
+int SomeClass::someMethod() {
+// CHECK-FIXES: {{^}}int SomeClass::SomeMethod() {
+    return 5;
+}
+
+} // namespace Inner
+
+void someFunc() {
+    Inner::SomeClass S;
+    S.someMethod<int>();
+// CHECK-FIXES: {{^}}    S.SomeMethod<int>();
+}
+
+} // namespace SomeNamespace