1 files changed, 248 insertions, 0 deletions
diff --git a/clang-tools-extra/test/clang-tidy/performance-move-const-arg.cpp b/clang-tools-extra/test/clang-tidy/performance-move-const-arg.cpp
new file mode 100644
index 00000000000..06ed6e0b56b
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/performance-move-const-arg.cpp
@@ -0,0 +1,248 @@
+// RUN: %check_clang_tidy %s performance-move-const-arg %t
+
+namespace std {
+template <typename>
+struct remove_reference;
+
+template <typename _Tp>
+struct remove_reference {
+  typedef _Tp type;
+};
+
+template <typename _Tp>
+struct remove_reference<_Tp &> {
+  typedef _Tp type;
+};
+
+template <typename _Tp>
+struct remove_reference<_Tp &&> {
+  typedef _Tp type;
+};
+
+template <typename _Tp>
+constexpr typename std::remove_reference<_Tp>::type &&move(_Tp &&__t) {
+  return static_cast<typename std::remove_reference<_Tp>::type &&>(__t);
+}
+
+template <typename _Tp>
+constexpr _Tp &&
+forward(typename remove_reference<_Tp>::type &__t) noexcept {
+  return static_cast<_Tp &&>(__t);
+}
+
+} // namespace std
+
+class A {
+public:
+  A() {}
+  A(const A &rhs) {}
+  A(A &&rhs) {}
+};
+
+struct TriviallyCopyable {
+  int i;
+};
+
+void f(TriviallyCopyable) {}
+
+void g() {
+  TriviallyCopyable obj;
+  f(std::move(obj));
+  // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: std::move of the variable 'obj' of the trivially-copyable type 'TriviallyCopyable' has no effect; remove std::move() [performance-move-const-arg]
+  // CHECK-FIXES: f(obj);
+}
+
+int f1() {
+  return std::move(42);
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the expression of the trivially-copyable type 'int' has no effect; remove std::move() [performance-move-const-arg]
+  // CHECK-FIXES: return 42;
+}
+
+int f2(int x2) {
+  return std::move(x2);
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the variable 'x2' of the trivially-copyable type 'int'
+  // CHECK-FIXES: return x2;
+}
+
+int *f3(int *x3) {
+  return std::move(x3);
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the variable 'x3' of the trivially-copyable type 'int *'
+  // CHECK-FIXES: return x3;
+}
+
+A f4(A x4) { return std::move(x4); }
+
+A f5(const A x5) {
+  return std::move(x5);
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the const variable 'x5' has no effect; remove std::move() or make the variable non-const [performance-move-const-arg]
+  // CHECK-FIXES: return x5;
+}
+
+template <typename T>
+T f6(const T x6) {
+  return std::move(x6);
+}
+
+void f7() { int a = f6(10); }
+
+#define M1(x) x
+void f8() {
+  const A a;
+  M1(A b = std::move(a);)
+  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: std::move of the const variable 'a' has no effect; remove std::move() or make the variable non-const
+  // CHECK-FIXES: M1(A b = a;)
+}
+
+#define M2(x) std::move(x)
+int f9() { return M2(1); }
+
+template <typename T>
+T f10(const int x10) {
+  return std::move(x10);
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the const variable 'x10' of the trivially-copyable type 'const int' has no effect; remove std::move() [performance-move-const-arg]
+  // CHECK-FIXES: return x10;
+}
+void f11() {
+  f10<int>(1);
+  f10<double>(1);
+}
+
+class NoMoveSemantics {
+public:
+  NoMoveSemantics();
+  NoMoveSemantics(const NoMoveSemantics &);
+
+  NoMoveSemantics &operator=(const NoMoveSemantics &);
+};
+
+void callByConstRef(const NoMoveSemantics &);
+void callByConstRef(int i, const NoMoveSemantics &);
+
+void moveToConstReferencePositives() {
+  NoMoveSemantics obj;
+
+  // Basic case.
+  callByConstRef(std::move(obj));
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: passing result of std::move() as
+  // CHECK-FIXES: callByConstRef(obj);
+
+  // Also works for second argument.
+  callByConstRef(1, std::move(obj));
+  // CHECK-MESSAGES: :[[@LINE-1]]:21: warning: passing result of std::move() as
+  // CHECK-FIXES: callByConstRef(1, obj);
+
+  // Works if std::move() applied to a temporary.
+  callByConstRef(std::move(NoMoveSemantics()));
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: passing result of std::move() as
+  // CHECK-FIXES: callByConstRef(NoMoveSemantics());
+
+  // Works if calling a copy constructor.
+  NoMoveSemantics other(std::move(obj));
+  // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: passing result of std::move() as
+  // CHECK-FIXES: NoMoveSemantics other(obj);
+
+  // Works if calling assignment operator.
+  other = std::move(obj);
+  // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: passing result of std::move() as
+  // CHECK-FIXES: other = obj;
+}
+
+class MoveSemantics {
+public:
+  MoveSemantics();
+  MoveSemantics(MoveSemantics &&);
+
+  MoveSemantics &operator=(MoveSemantics &&);
+};
+
+void callByValue(MoveSemantics);
+
+void callByRValueRef(MoveSemantics &&);
+
+template <class T>
+void templateFunction(T obj) {
+  T other = std::move(obj);
+}
+
+#define M3(T, obj)            \
+  do {                        \
+    T other = std::move(obj); \
+  } while (true)
+
+#define CALL(func) (func)()
+
+void moveToConstReferenceNegatives() {
+  // No warning when actual move takes place.
+  MoveSemantics move_semantics;
+  callByValue(std::move(move_semantics));
+  callByRValueRef(std::move(move_semantics));
+  MoveSemantics other(std::move(move_semantics));
+  other = std::move(move_semantics);
+
+  // No warning if std::move() not used.
+  NoMoveSemantics no_move_semantics;
+  callByConstRef(no_move_semantics);
+
+  // No warning if instantiating a template.
+  templateFunction(no_move_semantics);
+
+  // No warning inside of macro expansions.
+  M3(NoMoveSemantics, no_move_semantics);
+
+  // No warning inside of macro expansion, even if the macro expansion is inside
+  // a lambda that is, in turn, an argument to a macro.
+  CALL([no_move_semantics] { M3(NoMoveSemantics, no_move_semantics); });
+
+  auto lambda = [] {};
+  auto lambda2 = std::move(lambda);
+}
+
+class MoveOnly {
+public:
+  MoveOnly(const MoveOnly &other) = delete;
+  MoveOnly &operator=(const MoveOnly &other) = delete;
+  MoveOnly(MoveOnly &&other) = default;
+  MoveOnly &operator=(MoveOnly &&other) = default;
+};
+template <class T>
+void Q(T);
+void moveOnlyNegatives(MoveOnly val) {
+  Q(std::move(val));
+}
+
+void fmovable(MoveSemantics);
+
+void lambda1() {
+  auto f = [](MoveSemantics m) {
+    fmovable(std::move(m));
+  };
+  f(MoveSemantics());
+}
+
+template<class T> struct function {};
+
+template<typename Result, typename... Args>
+class function<Result(Args...)> {
+public:
+  function() = default;
+  void operator()(Args... args) const {
+    fmovable(std::forward<Args>(args)...);
+  }
+};
+
+void functionInvocation() {
+  function<void(MoveSemantics)> callback;
+  MoveSemantics m;
+  callback(std::move(m));
+}
+
+void lambda2() {
+  function<void(MoveSemantics)> callback;
+
+  auto f = [callback = std::move(callback)](MoveSemantics m) mutable {
+    // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: std::move of the variable 'callback' of the trivially-copyable type 'function<void (MoveSemantics)>' has no effect; remove std::move()
+    // CHECK-FIXES: auto f = [callback = callback](MoveSemantics m) mutable {
+    callback(std::move(m));
+  };
+  f(MoveSemantics());
+}