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
test_f0()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
test_f1()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