modernize-pass-by-value.cpp
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// RUN: %check_clang_tidy %s modernize-pass-by-value %t -- -- -fno-delayed-template-parsing
namespace {
// POD types are trivially move constructible.
struct POD {
int a, b, c;
};
struct Movable {
int a, b, c;
Movable() = default;
Movable(const Movable &) {}
Movable(Movable &&) {}
};
struct NotMovable {
NotMovable() = default;
NotMovable(const NotMovable &) = default;
NotMovable(NotMovable &&) = delete;
int a, b, c;
};
}
struct A {
A(const Movable &M) : M(M) {}
// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: pass by value and use std::move [modernize-pass-by-value]
// CHECK-FIXES: A(Movable M) : M(std::move(M)) {}
Movable M;
};
// Test that we aren't modifying other things than a parameter.
Movable GlobalObj;
struct B {
B(const Movable &M) : M(GlobalObj) {}
// CHECK-FIXES: B(const Movable &M) : M(GlobalObj) {}
Movable M;
};
// Test that a parameter with more than one reference to it won't be changed.
struct C {
// Tests extra-reference in body.
C(const Movable &M) : M(M) { this->i = M.a; }
// CHECK-FIXES: C(const Movable &M) : M(M) { this->i = M.a; }
// Tests extra-reference in init-list.
C(const Movable &M, int) : M(M), i(M.a) {}
// CHECK-FIXES: C(const Movable &M, int) : M(M), i(M.a) {}
Movable M;
int i;
};
// Test that both declaration and definition are updated.
struct D {
D(const Movable &M);
// CHECK-FIXES: D(Movable M);
Movable M;
};
D::D(const Movable &M) : M(M) {}
// CHECK-MESSAGES: :[[@LINE-1]]:6: warning: pass by value and use std::move
// CHECK-FIXES: D::D(Movable M) : M(std::move(M)) {}
// Test with default parameter.
struct E {
E(const Movable &M = Movable()) : M(M) {}
// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: pass by value and use std::move
// CHECK-FIXES: E(Movable M = Movable()) : M(std::move(M)) {}
Movable M;
};
// Test with object that can't be moved.
struct F {
F(const NotMovable &NM) : NM(NM) {}
// CHECK-FIXES: F(const NotMovable &NM) : NM(NM) {}
NotMovable NM;
};
// Test unnamed parameter in declaration.
struct G {
G(const Movable &);
// CHECK-FIXES: G(Movable );
Movable M;
};
G::G(const Movable &M) : M(M) {}
// CHECK-MESSAGES: :[[@LINE-1]]:6: warning: pass by value and use std::move
// CHECK-FIXES: G::G(Movable M) : M(std::move(M)) {}
// Test parameter with and without qualifier.
namespace ns_H {
typedef ::Movable HMovable;
}
struct H {
H(const ns_H::HMovable &M);
// CHECK-FIXES: H(ns_H::HMovable M);
ns_H::HMovable M;
};
using namespace ns_H;
H::H(const HMovable &M) : M(M) {}
// CHECK-MESSAGES: :[[@LINE-1]]:6: warning: pass by value and use std::move
// CHECK-FIXES: H(HMovable M) : M(std::move(M)) {}
// Try messing up with macros.
#define MOVABLE_PARAM(Name) const Movable & Name
// CHECK-FIXES: #define MOVABLE_PARAM(Name) const Movable & Name
struct I {
I(MOVABLE_PARAM(M)) : M(M) {}
// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: pass by value and use std::move
// CHECK-FIXES: I(MOVABLE_PARAM(M)) : M(M) {}
Movable M;
};
#undef MOVABLE_PARAM
// Test that templates aren't modified.
template <typename T> struct J {
J(const T &M) : M(M) {}
// CHECK-FIXES: J(const T &M) : M(M) {}
T M;
};
J<Movable> j1(Movable());
J<NotMovable> j2(NotMovable());
template<class T>
struct MovableTemplateT
{
MovableTemplateT() {}
MovableTemplateT(const MovableTemplateT& o) { }
MovableTemplateT(MovableTemplateT&& o) { }
};
template <class T>
struct J2 {
J2(const MovableTemplateT<T>& A);
// CHECK-FIXES: J2(const MovableTemplateT<T>& A);
MovableTemplateT<T> M;
};
template <class T>
J2<T>::J2(const MovableTemplateT<T>& A) : M(A) {}
// CHECK-FIXES: J2<T>::J2(const MovableTemplateT<T>& A) : M(A) {}
J2<int> j3(MovableTemplateT<int>{});
struct K_Movable {
K_Movable() = default;
K_Movable(const K_Movable &) = default;
K_Movable(K_Movable &&o) { dummy = o.dummy; }
int dummy;
};
// Test with movable type with an user defined move constructor.
struct K {
K(const K_Movable &M) : M(M) {}
// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: pass by value and use std::move
// CHECK-FIXES: K(K_Movable M) : M(std::move(M)) {}
K_Movable M;
};
template <typename T> struct L {
L(const Movable &M) : M(M) {}
// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: pass by value and use std::move
// CHECK-FIXES: L(Movable M) : M(std::move(M)) {}
Movable M;
};
L<int> l(Movable());
// Test with a non-instantiated template class.
template <typename T> struct N {
N(const Movable &M) : M(M) {}
// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: pass by value and use std::move
// CHECK-FIXES: N(Movable M) : M(std::move(M)) {}
Movable M;
T A;
};
// Test with value parameter.
struct O {
O(Movable M) : M(M) {}
// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: pass by value and use std::move
// CHECK-FIXES: O(Movable M) : M(std::move(M)) {}
Movable M;
};
// Test with a const-value parameter.
struct P {
P(const Movable M) : M(M) {}
// CHECK-FIXES: P(const Movable M) : M(M) {}
Movable M;
};
// Test with multiples parameters where some need to be changed and some don't.
// need to.
struct Q {
Q(const Movable &A, const Movable &B, const Movable &C, double D)
: A(A), B(B), C(C), D(D) {}
// CHECK-MESSAGES: :[[@LINE-2]]:23: warning: pass by value and use std::move
// CHECK-MESSAGES: :[[@LINE-3]]:41: warning: pass by value and use std::move
// CHECK-FIXES: Q(const Movable &A, Movable B, Movable C, double D)
// CHECK-FIXES: : A(A), B(std::move(B)), C(std::move(C)), D(D) {}
const Movable &A;
Movable B;
Movable C;
double D;
};
// Test that value-parameters with a nested name specifier are left as-is.
namespace ns_R {
typedef ::Movable RMovable;
}
struct R {
R(ns_R::RMovable M) : M(M) {}
// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: pass by value and use std::move
// CHECK-FIXES: R(ns_R::RMovable M) : M(std::move(M)) {}
ns_R::RMovable M;
};
// Test with rvalue parameter.
struct S {
S(Movable &&M) : M(M) {}
// CHECK-FIXES: S(Movable &&M) : M(M) {}
Movable M;
};
template <typename T, int N> struct array { T A[N]; };
// Test that types that are trivially copyable will not use std::move. This will
// cause problems with performance-move-const-arg, as it will revert it.
struct T {
T(array<int, 10> a) : a_(a) {}
// CHECK-FIXES: T(array<int, 10> a) : a_(a) {}
array<int, 10> a_;
};
struct U {
U(const POD &M) : M(M) {}
POD M;
};