[clang-tidy] Do not trigger move fix for non-copy assignment operators in performance-unnecessary-value-param check

Reviewers: alexfh, sbenza, malcolm.parsons

Subscribers: JDevlieghere, cfe-commits

Differential Revision: https://reviews.llvm.org/D28899

llvm-svn: 292491

2 files changed, 13 insertions, 1 deletions

diff --git a/clang-tools-extra/clang-tidy/utils/DeclRefExprUtils.cpp b/clang-tools-extra/clang-tidy/utils/DeclRefExprUtils.cpp
index a28b1d25a04..06acd310170 100644
--- a/clang-tools-extra/clang-tidy/utils/DeclRefExprUtils.cpp
+++ b/clang-tools-extra/clang-tidy/utils/DeclRefExprUtils.cpp
@@ -159,7 +159,8 @@ bool isCopyAssignmentArgument(const DeclRefExpr &DeclRef, const Decl &Decl,
       parmVarDecl(hasType(matchers::isReferenceToConst())));
   auto Matches = match(
       decl(hasDescendant(
-          cxxOperatorCallExpr(UsedAsConstRefArg, hasOverloadedOperatorName("="))
+          cxxOperatorCallExpr(UsedAsConstRefArg, hasOverloadedOperatorName("="),
+                              callee(cxxMethodDecl(isCopyAssignmentOperator())))
               .bind("operatorCallExpr"))),
       Decl, Context);
   return !Matches.empty();
diff --git a/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param.cpp b/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param.cpp
index cf12d2ccd8c..dfd545ab2b7 100644
--- a/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param.cpp
+++ b/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param.cpp
@@ -247,6 +247,17 @@ void PositiveMoveOnCopyAssignment(ExpensiveMovableType E) {
   // CHECK-FIXES: F = std::move(E);
 }
 
+struct NotCopyAssigned {
+  NotCopyAssigned &operator=(const ExpensiveMovableType &);
+};
+
+void PositiveNoMoveForNonCopyAssigmentOperator(ExpensiveMovableType E) {
+  // CHECK-MESSAGES: [[@LINE-1]]:69: warning: the parameter 'E' is copied
+  // CHECK-FIXES: void PositiveNoMoveForNonCopyAssigmentOperator(const ExpensiveMovableType& E) {
+  NotCopyAssigned N;
+  N = E;
+}
+
 // The argument could be moved but is not since copy statement is inside a loop.
 void PositiveNoMoveInsideLoop(ExpensiveMovableType E) {
   // CHECK-MESSAGES: [[@LINE-1]]:52: warning: the parameter 'E' is copied