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// { dg-do run { target c++20 } }
#include <cassert>
template<typename T>
concept C = __is_class(T);
template<typename T>
concept D = __is_empty(T);
struct X { } x;
struct Y { int n; } y;
int called = 0;
// Test constrained member definitions
template<typename T>
struct S1 {
void f1() requires C<T> { }
void f2() requires C<T> { called = 1; }
void f2() requires (not C<T>) { called = 2; }
void f3() { called = 1; }
void f3() requires C<T> { called = 2; }
void f3() requires C<T> and D<T> { called = 3; }
void g1() requires C<T> and true;
void g2() requires C<T>;
void g2() requires (not C<T>);
void g3();
void g3() requires C<T>;
void g3() requires C<T> and D<T>;
template<C U> void h1(U u) { called = 1; }
template<C U> void h2(U u);
template<C U> void h3(U u) requires D<U>;
};
template<C T>
struct S2 {
void f(T) requires D<T>;
};
int main() {
S1<X> sx;
S1<Y> sy;
S1<int> si;
// Defined in-class
sx.f1();
sx.f2(); assert(called == 1);
sx.f3(); assert(called == 3);
sy.f1();
sy.f2(); assert(called == 1);
sy.f3(); assert(called == 2);
si.f2(); assert(called == 2);
si.f3(); assert(called == 1);
// Member function template tests
S1<int> s1i;
s1i.h1(x); assert(called == 1);
s1i.h2(x); assert(called == 2);
s1i.h3(x); assert(called == 3);
// Defined out of class.
sx.g1();
sx.g2(); assert(called == 1);
sx.g3(); assert(called == 3);
sy.g1();
sy.g2(); assert(called == 1);
sy.g3(); assert(called == 2);
si.g2(); assert(called == 2);
si.g3(); assert(called == 1);
}
template<typename T>
void S1<T>::g1() requires C<T> and true { }
template<typename T>
void S1<T>::g2() requires C<T> { called = 1; }
template<typename T>
void S1<T>::g2() requires (not C<T>) { called = 2; }
template<typename T>
void S1<T>::g3() { called = 1; }
template<typename T>
void S1<T>::g3() requires C<T> { called = 2; }
template<typename T>
void S1<T>::g3() requires C<T> and D<T> { called = 3; }
template<typename T>
template<C U>
void S1<T>::h2(U u) { called = 2; }
template<typename T>
template<C U>
void S1<T>::h3(U u) requires D<U> { called = 3; }
template<C T>
void S2<T>::f(T t) requires D<T> { called = 4; }
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