[clang-tidy] fix false positive in bugprone-return-const-ref-from-parameter

Author: jcsxky

clang-tools-extra/clang-tidy/bugprone/ReturnConstRefFromParameterCheck.cpp

@@ -21,10 +21,10 @@ void ReturnConstRefFromParameterCheck::registerMatchers(MatchFinder *Finder) {
               to(parmVarDecl(hasType(hasCanonicalType(
                                  qualType(lValueReferenceType(pointee(
                                               qualType(isConstQualified()))))
-                                     .bind("type"))))
+                                     .bind("type"))), parmVarDecl(hasDeclContext(functionDecl().bind("owner"))))
                      .bind("param")))),
           hasAncestor(
-              functionDecl(hasReturnTypeLoc(loc(qualType(
+              functionDecl(equalsBoundNode("owner"), hasReturnTypeLoc(loc(qualType(
                                hasCanonicalType(equalsBoundNode("type"))))))
                   .bind("func")))
           .bind("ret"),

clang-tools-extra/docs/ReleaseNotes.rst

@@ -104,6 +104,10 @@ New check aliases
 Changes in existing checks
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+- Improved :doc:`bugprone-return-const-ref-from-parameter
+  <clang-tidy/checks/bugprone/return-const-ref-from-parameter>` check by no longer
+  giving false positives for lambda.
+
 - Improved :doc:`readability-redundant-smartptr-get
   <clang-tidy/checks/readability/redundant-smartptr-get>` check to
   remove `->`, when reduntant `get()` is removed.

clang-tools-extra/test/clang-tidy/checkers/bugprone/return-const-ref-from-parameter.cpp

@@ -142,6 +142,12 @@ void instantiate(const int &param, const float &paramf, int &mut_param, float &m
         itf6(mut_paramf);
 }
 
+template<class T>
+void f(const T& t) {
+    const auto get = [&t] -> const T& { return t; };
+    return T{};
+}
+
 } // namespace valid
 
 namespace overload {