llvm-project/clang-tools-extra/test/clang-tidy/checkers/performance-move-const-arg.cpp

343 lines
12 KiB
C++

// 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());
}
void showInt(int &&v);
void showInt(int v1, int &&v2);
void showPointer(const char *&&s);
void showPointer2(const char *const &&s);
void showTriviallyCopyable(TriviallyCopyable &&obj);
void showTriviallyCopyablePointer(const TriviallyCopyable *&&obj);
void testFunctions() {
int a = 10;
showInt(std::move(a));
// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: std::move of the variable 'a' of the trivially-copyable type 'int' has no effect [performance-move-const-arg]
// CHECK-MESSAGES: :[[@LINE-10]]:20: note: consider changing the 1st parameter of 'showInt' from 'int &&' to 'const int &'
showInt(int());
showInt(a, std::move(a));
// CHECK-MESSAGES: :[[@LINE-1]]:14: warning: std::move of the variable 'a' of the trivially-copyable type 'int' has no effect [performance-move-const-arg]
// CHECK-MESSAGES: :[[@LINE-13]]:28: note: consider changing the 2nd parameter of 'showInt' from 'int &&' to 'const int &'
const char* s = "";
showPointer(std::move(s));
// CHECK-MESSAGES: :[[@LINE-1]]:15: warning: std::move of the variable 's' of the trivially-copyable type 'const char *' has no effect [performance-move-const-arg]
// CHECK-MESSAGES: :[[@LINE-16]]:32: note: consider changing the 1st parameter of 'showPointer' from 'const char *&&' to 'const char *'
showPointer2(std::move(s));
// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: std::move of the variable 's' of the trivially-copyable type 'const char *' has no effect [performance-move-const-arg]
// CHECK-MESSAGES: :[[@LINE-18]]:39: note: consider changing the 1st parameter of 'showPointer2' from 'const char *const &&' to 'const char *const'
TriviallyCopyable *obj = new TriviallyCopyable();
showTriviallyCopyable(std::move(*obj));
// CHECK-MESSAGES: :[[@LINE-1]]:25: warning: std::move of the expression of the trivially-copyable type 'TriviallyCopyable' has no effect [performance-move-const-arg]
// CHECK-MESSAGES: :[[@LINE-21]]:48: note: consider changing the 1st parameter of 'showTriviallyCopyable' from 'TriviallyCopyable &&' to 'const TriviallyCopyable &'
showTriviallyCopyablePointer(std::move(obj));
// CHECK-MESSAGES: :[[@LINE-1]]:32: warning: std::move of the variable 'obj' of the trivially-copyable type 'TriviallyCopyable *' has no effect [performance-move-const-arg]
// CHECK-MESSAGES: :[[@LINE-23]]:62: note: consider changing the 1st parameter of 'showTriviallyCopyablePointer' from 'const TriviallyCopyable *&&' to 'const TriviallyCopyable *'
}
template <class T>
void forwardToShowInt(T && t) {
showInt(static_cast<T &&>(t));
}
void testTemplate() {
int a = 10;
forwardToShowInt(std::move(a));
// CHECK-MESSAGES: :[[@LINE-1]]:20: warning: std::move of the variable 'a' of the trivially-copyable type 'int' has no effect [performance-move-const-arg]
}
struct Tmp {
Tmp();
Tmp(int &&a);
Tmp(int v1, int &&a);
Tmp(const char *&&s);
Tmp(TriviallyCopyable&& obj);
Tmp(const TriviallyCopyable *&&obj);
void showTmp(TriviallyCopyable&& t);
static void showTmpStatic(TriviallyCopyable&& t);
};
void testMethods() {
Tmp t;
int a = 10;
Tmp t1(std::move(a));
// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the variable 'a' of the trivially-copyable type 'int' has no effect [performance-move-const-arg]
// CHECK-MESSAGES: :[[@LINE-13]]:13: note: consider changing the 1st parameter of 'Tmp' from 'int &&' to 'const int &'
Tmp t2(a, std::move(a));
// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: std::move of the variable 'a' of the trivially-copyable type 'int' has no effect [performance-move-const-arg]
// CHECK-MESSAGES: :[[@LINE-15]]:21: note: consider changing the 2nd parameter of 'Tmp' from 'int &&' to 'const int &'
const char* s = "";
Tmp t3(std::move(s));
// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the variable 's' of the trivially-copyable type 'const char *' has no effect [performance-move-const-arg]
// CHECK-MESSAGES: :[[@LINE-18]]:21: note: consider changing the 1st parameter of 'Tmp' from 'const char *&&' to 'const char *'
TriviallyCopyable *obj = new TriviallyCopyable();
Tmp t4(std::move(*obj));
// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the expression of the trivially-copyable type 'TriviallyCopyable' has no effect [performance-move-const-arg]
// CHECK-MESSAGES: :[[@LINE-21]]:27: note: consider changing the 1st parameter of 'Tmp' from 'TriviallyCopyable &&' to 'const TriviallyCopyable &'
Tmp t5(std::move(obj));
// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the variable 'obj' of the trivially-copyable type 'TriviallyCopyable *' has no effect [performance-move-const-arg]
// CHECK-MESSAGES: :[[@LINE-23]]:34: note: consider changing the 1st parameter of 'Tmp' from 'const TriviallyCopyable *&&' to 'const TriviallyCopyable *'
t.showTmp(std::move(*obj));
// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: std::move of the expression of the trivially-copyable type 'TriviallyCopyable' has no effect [performance-move-const-arg]
// CHECK-MESSAGES: :[[@LINE-25]]:36: note: consider changing the 1st parameter of 'showTmp' from 'TriviallyCopyable &&' to 'const TriviallyCopyable &'
Tmp::showTmpStatic(std::move(*obj));
// CHECK-MESSAGES: :[[@LINE-1]]:22: warning: std::move of the expression of the trivially-copyable type 'TriviallyCopyable' has no effect [performance-move-const-arg]
// CHECK-MESSAGES: :[[@LINE-27]]:49: note: consider changing the 1st parameter of 'showTmpStatic' from 'TriviallyCopyable &&' to 'const TriviallyCopyable &'
}
void showA(A &&v) {}
void testA() {
A a;
showA(std::move(a));
}
void testFuncPointer() {
int a = 10;
void (*choice)(int, int &&);
choice = showInt;
choice(std::move(a), std::move(a));
// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the variable 'a' of the trivially-copyable type 'int' has no effect; remove std::move() [performance-move-const-arg]
// CHECK-FIXES: choice(a, std::move(a));
// CHECK-MESSAGES: :[[@LINE-3]]:24: warning: std::move of the variable 'a' of the trivially-copyable type 'int' has no effect [performance-move-const-arg]
}