#include <iostream>
 
#include <functional>
#include <type_traits>
 
class testClass
{
public:
   testClass() = default;
   testClass( const testClass & other ) { std::cout << "COPY C" << std::endl; }
   testClass & operator=(const testClass & other ) { std::cout << "COPY A" << std::endl; }
};
 
template< class T>
void testFunc(T && t)
   { [test = std::conditional_t<
                 std::is_lvalue_reference<T>::value,
                 std::reference_wrapper<std::remove_reference_t<T>>,
                 T>{std::forward<T>(t)}]{}(); }
 
int main()
{
   testClass x;
   std::cout << "PLEASE NO COPY" << std::endl;
   testFunc(x);
   std::cout << "DONE" << std::endl;
 
   std::cout << "COPY HERE" << std::endl;
   testFunc(testClass());
   std::cout << "DONE" << std::endl;
}

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