https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123237
--- Comment #10 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
// PR c++/123237
// { dg-do compile { target c++26 } }
// { dg-additional-options "-freflection" }
using info = decltype(^^::);
template<unsigned>
struct A { };
template<typename T>
struct B {
T t;
constexpr T fn () { return 42; }
};
struct Y {
int i;
using type = int;
};
namespace N {
struct NY {
int i;
};
}
template<typename T>
using U = [:^^T:];
template<info R>
constexpr auto f1 (typename [:R:] x) { return x; }
template<info R>
constexpr auto f2 (typename [:R:]::NY x) { return x; }
template<info R>
constexpr auto f3 () -> A<sizeof(typename [:R:])> { return {}; }
template<info R>
constexpr auto f4 () -> A<sizeof([:R:])> { return {}; }
template<info R>
constexpr auto f5 () -> decltype([:R:]) { return {}; }
template<typename T>
constexpr auto f6 (U<T> y) { return y; }
template<info R>
constexpr auto f7 (typename [:R:]<0> x) { return x; }
template<typename T>
constexpr auto f8 (typename [:^^T:] x) { return x; }
template<info R>
constexpr typename [:R:] f9 (int i) { return i; }
template<typename T>
constexpr T foo (T t) { return t; }
template<info R>
constexpr auto f10 () -> decltype(template [:R:](42)) { return {}; }
template<info R>
constexpr auto f11 (A<template [:R:](42)> a) { return a; }
template<typename T>
consteval info id () { return ^^T; }
template<typename T>
constexpr typename [:id<T>():] f12 () { return 42; }
template<info R>
constexpr auto f13 (typename [:R:]::type x) { return x; }
template<info R>
constexpr auto f14 () -> [:R:] { return {}; }
template<typename T, info R>
constexpr auto f15 () -> decltype(T{}.[:R:]) { return {}; }
template<typename T, info R>
constexpr auto f16 () -> decltype(T{}.template [:R:]()) { return {}; }
template<info O, info M>
constexpr auto f17 () -> decltype(typename [:O:]{}.[:M:]) { return {}; }
template<info M>
constexpr auto f18 () -> decltype(Y{}.[:M:]) { return {}; }
template<template<typename> class T>
constexpr auto f19 () -> [:^^T:]<int> { return {}; }
// splice-type-spec
constexpr auto a1 = f1<^^Y>(Y{ 42 });
// splice-scope-spec
constexpr auto a2 = f2<^^N>(N::NY{ 42 });
// splice-type-spec
constexpr auto a3 = f3<^^int>();
// splice-expr
int i;
constexpr auto a4 = f4<^^i>();
// splice-expr
constexpr auto a5 = f5<^^i>();
// splice-type-spec
constexpr auto a6 = f6<Y>(Y{42});
// splice-type-spec
constexpr auto a7 = f7<^^A>(A<0>{});
// splice-type-spec
constexpr auto a8 = f8<int>(42);
// splice-type-spec
constexpr auto a9 = f9<^^int>(42);
// splice-expr
constexpr auto a10 = f10<^^foo<int>>();
// splice-expr
constexpr auto a11 = f11<^^foo<int>>(A<42>{});
// splice-type-spec
constexpr auto a12 = f12<int>();
// splice-scope-spec
constexpr auto a13 = f13<^^Y>(42);
// splice-type-spec
constexpr auto a14 = f14<^^int>();
// splice-type-spec
constexpr auto a14b = f14<^^A<1>>();
// splice-expr
constexpr auto a15 = f15<Y, ^^Y::i>();
constexpr auto a15b = f15<B<int>, ^^B<int>::t>();
constexpr auto a16 = f16<B<int>, ^^B<int>::fn>();
// splice-type-spec
constexpr auto a17 = f17<^^Y, ^^Y::i>();
// splice-expr
constexpr auto a18 = f18<^^Y::i>();
// splice-type-spec
constexpr auto a19 = f19<B>();
