test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p3-0x.cpp

   1 // RUN: %clang_cc1 -std=c++0x -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 }