[clang-tools-extra] e856483 - [clang-tidy][doc] add more information in twine-local's document (#166266)

[via cfe-commits]

Author: Congcong Cai
Date: 2025-11-05T11:25:53Z
New Revision: e8564830c19e6fd5bfa38488c06f332b214ea858

URL: https://github.com/llvm/llvm-project/commit/e8564830c19e6fd5bfa38488c06f332b214ea858
DIFF: https://github.com/llvm/llvm-project/commit/e8564830c19e6fd5bfa38488c06f332b214ea858.diff

LOG: [clang-tidy][doc] add more information in twine-local's document (#166266)

explain more about use-after-free in llvm-twine-local
add note about manually adjusting code after applying fix-it.
fixed: #154810

Added: 
    

Modified: 
    clang-tools-extra/docs/clang-tidy/checks/llvm/twine-local.rst

Removed: 
    


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diff  --git a/clang-tools-extra/docs/clang-tidy/checks/llvm/twine-local.rst b/clang-tools-extra/docs/clang-tidy/checks/llvm/twine-local.rst
index ec9ef1c60913c..6c994a48d83de 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/llvm/twine-local.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/llvm/twine-local.rst
@@ -14,3 +14,21 @@ should be generally avoided.
   // becomes
 
   static std::string Moo = (Twine("bark") + "bah").str();
+
+The ``Twine`` does not own the memory of its contents, so it is not
+recommended to use ``Twine`` created from temporary strings or string literals.
+
+.. code-block:: c++
+
+  static Twine getModuleIdentifier(StringRef moduleName) {
+    return moduleName + "_module";
+  }
+  void foo() {
+    Twine result = getModuleIdentifier(std::string{"abc"} + "def");
+    // temporary std::string is destroyed here, result is dangling
+  }
+
+After applying this fix-it hints, the code will use ``std::string`` instead of
+``Twine`` for local variables. However, ``Twine`` has lots of methods that
+are incompatible with ``std::string``, so the user may need to adjust the code
+manually after applying the fix-it hints.