1 // RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s 2 3 4 // If P is an rvalue reference to a cv-unqualified template parameter 5 // and the argument is an lvalue, the type "lvalue reference to A" is 6 // used in place of A for type deduction. 7 template<typename T> struct X { }; 8 9 template<typename T> X<T> f0(T&&); 10 11 struct Y { }; 12 13 template<typename T> T prvalue(); 14 template<typename T> T&& xvalue(); 15 template<typename T> T& lvalue(); 16 17 void test_f0() { 18 X<int> xi0 = f0(prvalue<int>()); 19 X<int> xi1 = f0(xvalue<int>()); 20 X<int&> xi2 = f0(lvalue<int>()); 21 X<Y> xy0 = f0(prvalue<Y>()); 22 X<Y> xy1 = f0(xvalue<Y>()); 23 X<Y&> xy2 = f0(lvalue<Y>()); 24 } 25 26 template<typename T> X<T> f1(const T&&); // expected-note{{candidate function [with T = int] not viable: no known conversion from 'int' to 'const int &&' for 1st argument}} \ 27 // expected-note{{candidate function [with T = Y] not viable: no known conversion from 'Y' to 'const Y &&' for 1st argument}} 28 29 void test_f1() { 30 X<int> xi0 = f1(prvalue<int>()); 31 X<int> xi1 = f1(xvalue<int>()); 32 f1(lvalue<int>()); // expected-error{{no matching function for call to 'f1'}} 33 X<Y> xy0 = f1(prvalue<Y>()); 34 X<Y> xy1 = f1(xvalue<Y>()); 35 f1(lvalue<Y>()); // expected-error{{no matching function for call to 'f1'}} 36 } 37 38 namespace std_example { 39 template <class T> int f(T&&); 40 template <class T> int g(const T&&); // expected-note{{candidate function [with T = int] not viable: no known conversion from 'int' to 'const int &&' for 1st argument}} 41 42 int i; 43 int n1 = f(i); 44 int n2 = f(0); 45 int n3 = g(i); // expected-error{{no matching function for call to 'g'}} 46 } 47
