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// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s
// RUN: %clang_cc1 -std=c++1z -fsyntax-only -verify %s
// A forwarding reference is an rvalue reference to a cv-unqualified template
// parameter that does not represent a template parameter of a class template.
#if __cplusplus > 201402L
namespace ClassTemplateParamNotForwardingRef {
// This is not a forwarding reference.
template<typename T> struct A { // expected-note {{candidate}}
A(T&&); // expected-note {{expects an rvalue}}
};
int n;
A a = n; // expected-error {{no viable constructor or deduction guide}}
A b = 0;
A<int> *pb = &b;
// This is a forwarding reference.
template<typename T> A(T&&) -> A<T>;
A c = n;
A<int&> *pc = &c;
A d = 0;
A<int> *pd = &d;
template<typename T = void> struct B {
// This is a forwarding reference.
template<typename U> B(U &&);
};
B e = n;
B<void> *pe = &e;
}
#endif
// If P is a forwarding reference and the argument is an lvalue, the type
// "lvalue reference to A" is used in place of A for type deduction.
template<typename T> struct X { };
template<typename T> X<T> f0(T&&);
struct Y { };
template<typename T> T prvalue();
template<typename T> T&& xvalue();
template<typename T> T& lvalue();
void test_f0() {
X<int> xi0 = f0(prvalue<int>());
X<int> xi1 = f0(xvalue<int>());
X<int&> xi2 = f0(lvalue<int>());
X<Y> xy0 = f0(prvalue<Y>());
X<Y> xy1 = f0(xvalue<Y>());
X<Y&> xy2 = f0(lvalue<Y>());
}
template<typename T> X<T> f1(const T&&); // expected-note{{candidate function [with T = int] not viable: expects an rvalue for 1st argument}} \
// expected-note{{candidate function [with T = Y] not viable: expects an rvalue for 1st argument}}
void test_f1() {
X<int> xi0 = f1(prvalue<int>());
X<int> xi1 = f1(xvalue<int>());
f1(lvalue<int>()); // expected-error{{no matching function for call to 'f1'}}
X<Y> xy0 = f1(prvalue<Y>());
X<Y> xy1 = f1(xvalue<Y>());
f1(lvalue<Y>()); // expected-error{{no matching function for call to 'f1'}}
}
namespace std_example {
template <class T> int f(T&&);
template <class T> int g(const T&&); // expected-note{{candidate function [with T = int] not viable: expects an rvalue for 1st argument}}
int i;
int n1 = f(i);
int n2 = f(0);
int n3 = g(i); // expected-error{{no matching function for call to 'g'}}
#if __cplusplus > 201402L
template<class T> struct A { // expected-note {{candidate}}
template<class U>
A(T &&, U &&, int *); // expected-note {{[with T = int, U = int] not viable: expects an rvalue}}
A(T &&, int *); // expected-note {{requires 2}}
};
template<class T> A(T &&, int *) -> A<T>; // expected-note {{requires 2}}
int *ip;
A a{i, 0, ip}; // expected-error {{no viable constructor or deduction guide}}
A a0{0, 0, ip};
A a2{i, ip};
A<int> &a0r = a0;
A<int&> &a2r = a2;
#endif
}
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