Checking that some kind of constructor is called and followed by a swap

Author: negativ

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

@@ -68,7 +68,23 @@ void UnhandledSelfAssignmentCheck::registerMatchers(MatchFinder *Finder) {
   const auto HasNoNestedSelfAssign =
       cxxMethodDecl(unless(hasDescendant(cxxMemberCallExpr(callee(cxxMethodDecl(
           hasName("operator="), ofClass(equalsBoundNode("class"))))))));
-
+  
+  // Checking that some kind of constructor is called and followed by a `swap`:
+  // T& operator=(const T& other) {
+  //    T tmp{this->internal_data(), some, other, args};
+  //    swap(tmp);
+  //    return *this;
+  // }
+  const auto HasCopyAndSwap = cxxMethodDecl(
+      ofClass(cxxRecordDecl(unless(hasAncestor(classTemplateDecl())))),
+      hasDescendant(
+          stmt(hasDescendant(
+                   varDecl(hasType(cxxRecordDecl(equalsBoundNode("class"))))
+                       .bind("tmp_var")),
+               hasDescendant(callExpr(callee(functionDecl(hasName("swap"))),
+                                      hasAnyArgument(declRefExpr(to(varDecl(
+                                          equalsBoundNode("tmp_var"))))))))));
+    
   DeclarationMatcher AdditionalMatcher = cxxMethodDecl();
   if (WarnOnlyIfThisHasSuspiciousField) {
     // Matcher for standard smart pointers.
@@ -94,6 +110,7 @@ void UnhandledSelfAssignmentCheck::registerMatchers(MatchFinder *Finder) {
                                    HasReferenceParam, HasNoSelfCheck,
                                    unless(HasNonTemplateSelfCopy),
                                    unless(HasTemplateSelfCopy),
+                                   unless(HasCopyAndSwap),
                                    HasNoNestedSelfAssign, AdditionalMatcher)
                          .bind("copyAssignmentOperator"),
                      this);