#include <iostream>
#include <type_traits>
 
template< typename type >
type const & as_const( type const & ref )
    { return ref; }
 
template< typename type >
typename std::enable_if< ! std::is_reference< type >::value,
type >::type const as_const( type && val )
    { return std::move( val ); }
 
struct rng {
	struct it {
		it ( int in ) : i( in ) {}
 
		int i;
		int operator * () const { std::cout << "non-const\n"; return i; }
		it & operator ++ () { ++ i; return * this; }
		bool operator != ( it rhs ) { return i != rhs.i; }
	};
	struct cit : it {
		using it::it;
		int operator * () const { std::cout << "const\n"; return i; }
	};
	it begin() { return { 0 }; }
	it end() { return { 5 }; }
	cit begin() const { return { 0 }; }
	cit end() const { return { 5 }; }
 
	rng() { std::cout << "make range\n"; }
	rng( rng && ) { std::cout << "move range\n"; }
	rng( rng const & ) { std::cout << "copy range\n"; }
	~ rng() { std::cout << "destroy range\n"; }
};
 
int main () {
	std::cout << "non-const temp\n";
	for ( auto i : rng() ) ;
	std::cout << "\nconst temp\n";
	for ( auto i : as_const( rng() ) ) ;
	std::cout << "\nconst non-temp\n";
	rng r;
	for ( auto i : as_const( r ) ) ;
}
 

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