[clang-tools-extra] [clang-tidy] Fix false positive in readability-non-const-parameter for dependent expression (PR #177345)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-tools-extra

Author: mitchell (zeyi2)

<details>
<summary>Changes</summary>

Closes #<!-- -->176623

---
Full diff: https://github.com/llvm/llvm-project/pull/177345.diff


3 Files Affected:

- (modified) clang-tools-extra/clang-tidy/readability/NonConstParameterCheck.cpp (+9-5) 
- (modified) clang-tools-extra/docs/ReleaseNotes.rst (+4) 
- (modified) clang-tools-extra/test/clang-tidy/checkers/readability/non-const-parameter.cpp (+22) 


``````````diff
diff --git a/clang-tools-extra/clang-tidy/readability/NonConstParameterCheck.cpp b/clang-tools-extra/clang-tidy/readability/NonConstParameterCheck.cpp
index a8767db4a4ffc..2ecde56cd7af8 100644
--- a/clang-tools-extra/clang-tidy/readability/NonConstParameterCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/NonConstParameterCheck.cpp
@@ -26,11 +26,12 @@ void NonConstParameterCheck::registerMatchers(MatchFinder *Finder) {
   Finder->addMatcher(declRefExpr().bind("Ref"), this);
 
   // Analyse parameter usage in function.
-  Finder->addMatcher(stmt(anyOf(unaryOperator(hasAnyOperatorName("++", "--")),
-                                binaryOperator(), callExpr(), returnStmt(),
-                                cxxConstructExpr()))
-                         .bind("Mark"),
-                     this);
+  Finder->addMatcher(
+      stmt(anyOf(unaryOperator(hasAnyOperatorName("++", "--")),
+                 binaryOperator(), callExpr(), returnStmt(), cxxConstructExpr(),
+                 cxxUnresolvedConstructExpr()))
+          .bind("Mark"),
+      this);
   Finder->addMatcher(varDecl(hasInitializer(anything())).bind("Mark"), this);
 }
 
@@ -93,6 +94,9 @@ void NonConstParameterCheck::check(const MatchFinder::MatchResult &Result) {
           markCanNotBeConst(Arg->IgnoreParenCasts(), false);
         }
       }
+    } else if (const auto *CE = dyn_cast<CXXUnresolvedConstructExpr>(S)) {
+      for (const auto *Arg : CE->arguments())
+        markCanNotBeConst(Arg->IgnoreParenCasts(), true);
     } else if (const auto *R = dyn_cast<ReturnStmt>(S)) {
       markCanNotBeConst(R->getRetValue(), true);
     } else if (const auto *U = dyn_cast<UnaryOperator>(S)) {
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 5af634c77f54d..89639828d0efe 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -137,6 +137,10 @@ Changes in existing checks
   now uses separate note diagnostics for each uninitialized enumerator, making
   it easier to see which specific enumerators need explicit initialization.
 
+- Improved :doc:`readability-non-const-parameter
+  <clang-tidy/checks/readability/non-const-parameter>` check by avoiding false
+  positives on parameters used in dependent expressions.
+
 Removed checks
 ^^^^^^^^^^^^^^
 
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/non-const-parameter.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/non-const-parameter.cpp
index a118c320bdae9..82a7715b63ae7 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/non-const-parameter.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/non-const-parameter.cpp
@@ -341,3 +341,25 @@ void constructLVRef(int *p) {
   // CHECK-MESSAGES-NOT: warning: pointer parameter 'p' can be
   Temp1 t(*p);
 }
+
+template<bool>
+class A final {
+    char* sz_ = {};
+
+public:
+    explicit A(char* sz) noexcept : sz_(sz) {}
+    void f() { sz_ = {}; }
+};
+
+class B final {
+    char* sz_ = {};
+
+public:
+    explicit B(char* sz) noexcept : sz_(sz) {}
+    void f() { sz_ = {}; }
+};
+
+void gh176623() {
+    auto const _ = []<bool tc>(char* p) { auto _ = A<tc>(p); };
+    auto const _ = []<bool tc>(char* p) { auto _ = B(p); };
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/177345