| // RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify %s |
| |
| // expected-no-diagnostics |
| |
| template <class T, class U> constexpr bool is_same_v = false; |
| template <class T> constexpr bool is_same_v<T, T> = true; |
| template <class T, class U> |
| concept is_same = is_same_v<T, U>; |
| |
| template <class T> struct X {}; |
| template <class T, class U> |
| concept C1 = is_same<T, X<U>>; |
| |
| template <class T1> X<X<X<T1>>> t1() { |
| return []<class T2>(T2) -> X<X<T2>> { |
| struct S { |
| static X<X<T2>> f() { |
| return []<class T3>(T3) -> X<T3> { |
| static_assert(is_same<T2, X<T1>>); |
| static_assert(is_same<T3, X<T2>>); |
| return X<T3>(); |
| }(X<T2>()); |
| } |
| }; |
| return S::f(); |
| }(X<T1>()); |
| }; |
| template X<X<X<int>>> t1<int>(); |
| |
| #if 0 // FIXME: crashes |
| template<class T1> auto t2() { |
| return []<class T2>(T2) { |
| struct S { |
| static auto f() { |
| return []<class T3>(T3) { |
| static_assert(is_same<T2, X<T1>>); |
| static_assert(is_same<T3, X<T2>>); |
| return X<T3>(); |
| }(X<T2>()); |
| } |
| }; |
| return S::f(); |
| }(X<T1>()); |
| }; |
| template auto t2<int>(); |
| static_assert(is_same<decltype(t2<int>()), X<X<X<int>>>>); |
| |
| template<class T1> C1<X<X<T1>>> auto t3() { |
| return []<C1<T1> T2>(T2) -> C1<X<T2>> auto { |
| struct S { |
| static auto f() { |
| return []<C1<T2> T3>(T3) -> C1<T3> auto { |
| return X<T3>(); |
| }(X<T2>()); |
| } |
| }; |
| return S::f(); |
| }(X<T1>()); |
| }; |
| template C1<X<X<int>>> auto t3<int>(); |
| static_assert(is_same<decltype(t3<int>()), X<X<X<int>>>>); |
| #endif |