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// DR 339

//

// Test of the use of free functions with SFINAE

void foo(int) { }

template void foo(T*) { }

typedef char yes_type;

struct no_type { char data[2]; };

template T create_a();

template struct enable_if { typedef T type; };

template struct enable_if { };

template

  typename enable_if<(sizeof(foo(create_a()), 1) > 0),

                     yes_type>::type

  check_has_foo(const volatile T&);

no_type check_has_foo(...);

template

struct has_foo

{

  static const bool value =

    (sizeof(check_has_foo(create_a())) == sizeof(yes_type));

};

struct X { };

int a1[has_foo::value? 1 : -1];

int a2[has_foo::value? 1 : -1];

int a3[has_foo::value? 1 : -1];

int a4[has_foo::value? -1 : 1];

int a5[has_foo::value? -1 : 1];