// RUN: %clang_cc1 -fsyntax-only -verify -std=c++20 -DSTD1 %s
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++20 -DSTD2 %s
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++20 -DSTD3 %s

namespace std {

#ifdef STD1
template <typename T>
struct is_trivially_relocatable {
    static constexpr bool value = __builtin_is_cpp_trivially_relocatable(T);
};

template <typename T>
constexpr bool is_trivially_relocatable_v = __builtin_is_cpp_trivially_relocatable(T);

template <typename T>
struct is_trivially_copyable {
    static constexpr bool value = __is_trivially_copyable(T);
};

template <typename T>
constexpr bool is_trivially_copyable_v = __is_trivially_copyable(T);

template <typename T, typename U>
struct is_assignable {
    static constexpr bool value = __is_assignable(T, U);
};

template <typename T, typename U>
constexpr bool is_assignable_v = __is_assignable(T, U);

template <typename T>
struct is_empty {
    static constexpr bool value = __is_empty(T);
};
template <typename T>
constexpr bool is_empty_v = __is_empty(T);

template <typename T>
struct is_standard_layout {
static constexpr bool value = __is_standard_layout(T);
};
template <typename T>
constexpr bool is_standard_layout_v = __is_standard_layout(T);

template <typename... Args>
struct is_constructible {
    static constexpr bool value = __is_constructible(Args...);
};

template <typename... Args>
constexpr bool is_constructible_v = __is_constructible(Args...);

template <typename T>
struct is_aggregate {
    static constexpr bool value = __is_aggregate(T);
};

template <typename T>
constexpr bool is_aggregate_v = __is_aggregate(T);

template <typename T>
struct is_final {
    static constexpr bool value = __is_final(T);
};
template <typename T>
constexpr bool is_final_v = __is_final(T);

template <typename T>
struct is_abstract {
    static constexpr bool value = __is_abstract(T);
};
template <typename T>
constexpr bool is_abstract_v = __is_abstract(T);

#endif

#ifdef STD2
template <typename T>
struct __details_is_trivially_relocatable {
    static constexpr bool value = __builtin_is_cpp_trivially_relocatable(T);
};

template <typename T>
using is_trivially_relocatable  = __details_is_trivially_relocatable<T>;

template <typename T>
constexpr bool is_trivially_relocatable_v = __builtin_is_cpp_trivially_relocatable(T);

template <typename T>
struct __details_is_trivially_copyable {
    static constexpr bool value = __is_trivially_copyable(T);
};

template <typename T>
using is_trivially_copyable  = __details_is_trivially_copyable<T>;

template <typename T>
constexpr bool is_trivially_copyable_v = __is_trivially_copyable(T);

template <typename T, typename U>
struct __details_is_assignable {
    static constexpr bool value = __is_assignable(T, U);
};

template <typename T, typename U>
using is_assignable = __details_is_assignable<T, U>;

template <typename T, typename U>
constexpr bool is_assignable_v = __is_assignable(T, U);

template <typename T>
struct __details_is_empty {
  static constexpr bool value = __is_empty(T);
};
template <typename T>
using is_empty  = __details_is_empty<T>;
template <typename T>
constexpr bool is_empty_v = __is_empty(T);

template <typename T>
struct __details_is_standard_layout {
    static constexpr bool value = __is_standard_layout(T);
};
template <typename T>
using is_standard_layout = __details_is_standard_layout<T>;
template <typename T>
constexpr bool is_standard_layout_v = __is_standard_layout(T);

template <typename... Args>
struct __details_is_constructible{
    static constexpr bool value = __is_constructible(Args...);
};

template <typename... Args>
using is_constructible  = __details_is_constructible<Args...>;

template <typename... Args>
constexpr bool is_constructible_v = __is_constructible(Args...);

template <typename T>
struct __details_is_aggregate {
    static constexpr bool value = __is_aggregate(T);
};

template <typename T>
using is_aggregate  = __details_is_aggregate<T>;

template <typename T>
constexpr bool is_aggregate_v = __is_aggregate(T);

template <typename T>
struct __details_is_final {
    static constexpr bool value = __is_final(T);
};
template <typename T>
using is_final = __details_is_final<T>;
template <typename T>
constexpr bool is_final_v = __is_final(T);

template <typename T>
struct __details_is_abstract {
    static constexpr bool value = __is_abstract(T);
};
template <typename T>
using is_abstract = __details_is_abstract<T>;
template <typename T>
constexpr bool is_abstract_v = __is_abstract(T);

#endif


#ifdef STD3
template< class T, T v >
struct integral_constant {
    static constexpr T value = v;
};

template< bool B >
using bool_constant = integral_constant<bool, B>;

template <typename T>
struct __details_is_trivially_relocatable : bool_constant<__builtin_is_cpp_trivially_relocatable(T)> {};

template <typename T>
using is_trivially_relocatable  = __details_is_trivially_relocatable<T>;

template <typename T>
constexpr bool is_trivially_relocatable_v = is_trivially_relocatable<T>::value;

template <typename T>
struct __details_is_trivially_copyable : bool_constant<__is_trivially_copyable(T)> {};

template <typename T>
using is_trivially_copyable  = __details_is_trivially_copyable<T>;

template <typename T>
constexpr bool is_trivially_copyable_v = is_trivially_copyable<T>::value;

template <typename T, typename U>
struct __details_is_assignable : bool_constant<__is_assignable(T, U)> {};

template <typename T, typename U>
using is_assignable  = __details_is_assignable<T, U>;

template <typename T, typename U>
constexpr bool is_assignable_v = is_assignable<T, U>::value;

template <typename T>
struct __details_is_empty : bool_constant<__is_empty(T)> {};
template <typename T>
using is_empty  = __details_is_empty<T>;
template <typename T>
constexpr bool is_empty_v = is_empty<T>::value;

template <typename T>
struct __details_is_standard_layout : bool_constant<__is_standard_layout(T)> {};
template <typename T>
using is_standard_layout = __details_is_standard_layout<T>;
template <typename T>
constexpr bool is_standard_layout_v = is_standard_layout<T>::value;

template <typename... Args>
struct __details_is_constructible : bool_constant<__is_constructible(Args...)> {};

template <typename... Args>
using is_constructible = __details_is_constructible<Args...>;

template <typename... Args>
constexpr bool is_constructible_v = is_constructible<Args...>::value;

template <typename T>
struct __details_is_aggregate : bool_constant<__is_aggregate(T)> {};

template <typename T>
using is_aggregate = __details_is_aggregate<T>;

template <typename T>
constexpr bool is_aggregate_v = is_aggregate<T>::value;

template <typename T>
struct __details_is_final : bool_constant<__is_final(T)> {};
template <typename T>
using is_final = __details_is_final<T>;
template <typename T>
constexpr bool is_final_v = is_final<T>::value;

template <typename T>
struct __details_is_abstract : bool_constant<__is_abstract(T)> {};
template <typename T>
using is_abstract = __details_is_abstract<T>;
template <typename T>
constexpr bool is_abstract_v = is_abstract<T>::value;

#endif
}

static_assert(std::is_trivially_relocatable<int>::value);

static_assert(std::is_trivially_relocatable<int&>::value);
// expected-error-re@-1 {{static assertion failed due to requirement 'std::{{.*}}is_trivially_relocatable<int &>::value'}} \
// expected-note@-1 {{'int &' is not trivially relocatable}} \
// expected-note@-1 {{because it is a reference type}}
static_assert(std::is_trivially_relocatable_v<int&>);
// expected-error@-1 {{static assertion failed due to requirement 'std::is_trivially_relocatable_v<int &>'}} \
// expected-note@-1 {{'int &' is not trivially relocatable}} \
// expected-note@-1 {{because it is a reference type}}

static_assert(std::is_trivially_copyable<int>::value);

static_assert(std::is_trivially_copyable<int&>::value);
// expected-error-re@-1 {{static assertion failed due to requirement 'std::{{.*}}is_trivially_copyable<int &>::value'}} \
// expected-note@-1 {{'int &' is not trivially copyable}} \
// expected-note@-1 {{because it is a reference type}}
static_assert(std::is_trivially_copyable_v<int&>);
// expected-error@-1 {{static assertion failed due to requirement 'std::is_trivially_copyable_v<int &>'}} \
// expected-note@-1 {{'int &' is not trivially copyable}} \
// expected-note@-1 {{because it is a reference type}}


 // Direct tests
 static_assert(std::is_standard_layout<int>::value);
 static_assert(std::is_standard_layout_v<int>);

 static_assert(std::is_standard_layout<int&>::value);
 // expected-error-re@-1 {{static assertion failed due to requirement 'std::{{.*}}is_standard_layout<int &>::value'}} \
 // expected-note@-1 {{'int &' is not standard-layout}} \
 // expected-note@-1 {{because it is a reference type}}

 static_assert(std::is_standard_layout_v<int&>);
 // expected-error@-1 {{static assertion failed due to requirement 'std::is_standard_layout_v<int &>'}} \
 // expected-note@-1 {{'int &' is not standard-layout}} \
 // expected-note@-1 {{because it is a reference type}}

static_assert(!std::is_empty<int>::value);

static_assert(std::is_empty<int&>::value);
// expected-error-re@-1 {{static assertion failed due to requirement 'std::{{.*}}is_empty<int &>::value'}} \
// expected-note@-1 {{'int &' is not empty}} \
// expected-note@-1 {{because it is a reference type}}
static_assert(std::is_empty_v<int&>);
// expected-error@-1 {{static assertion failed due to requirement 'std::is_empty_v<int &>'}} \
// expected-note@-1 {{'int &' is not empty}} \
// expected-note@-1 {{because it is a reference type}}


static_assert(std::is_assignable<int&, int>::value);

static_assert(std::is_assignable<int&, void>::value);
// expected-error-re@-1 {{static assertion failed due to requirement 'std::{{.*}}is_assignable<int &, void>::value'}} \
// expected-error@-1 {{assigning to 'int' from incompatible type 'void'}}
static_assert(std::is_assignable_v<int&, void>);
// expected-error@-1 {{static assertion failed due to requirement 'std::is_assignable_v<int &, void>'}} \
// expected-error@-1 {{assigning to 'int' from incompatible type 'void'}}

static_assert(std::is_constructible<int, int>::value);

static_assert(std::is_constructible<void>::value);
// expected-error-re@-1 {{static assertion failed due to requirement 'std::{{.*}}is_constructible<void>::value'}} \
// expected-note@-1 {{because it is a cv void type}}
static_assert(std::is_constructible_v<void>);
// expected-error@-1 {{static assertion failed due to requirement 'std::is_constructible_v<void>'}} \
// expected-note@-1 {{because it is a cv void type}}

static_assert(!std::is_final<int>::value);

static_assert(std::is_final<int&>::value);
// expected-error-re@-1 {{static assertion failed due to requirement 'std::{{.*}}is_final<int &>::value'}} \
// expected-note@-1 {{'int &' is not final}} \
// expected-note@-1 {{because it is a reference type}} \
// expected-note@-1 {{because it is not a class or union type}}

static_assert(std::is_final_v<int&>);
// expected-error@-1 {{static assertion failed due to requirement 'std::is_final_v<int &>'}} \
// expected-note@-1 {{'int &' is not final}} \
// expected-note@-1 {{because it is a reference type}} \
// expected-note@-1 {{because it is not a class or union type}}

using Arr = int[3];
static_assert(std::is_final<Arr>::value);
// expected-error-re@-1 {{static assertion failed due to requirement 'std::{{.*}}is_final<int[3]>::value'}} \
// expected-note@-1 {{'Arr' (aka 'int[3]') is not final}} \
// expected-note@-1 {{because it is not a class or union type}}

static_assert(std::is_final_v<Arr>);
// expected-error@-1 {{static assertion failed due to requirement 'std::is_final_v<int[3]>'}} \
// expected-note@-1 {{'int[3]' is not final}} \
// expected-note@-1 {{because it is not a class or union type}}


static_assert(!std::is_aggregate<int>::value);

static_assert(std::is_aggregate<void>::value);
// expected-error-re@-1 {{static assertion failed due to requirement 'std::{{.*}}is_aggregate<void>::value'}} \
// expected-note@-1 {{'void' is not aggregate}} \
// expected-note@-1 {{because it is a cv void type}}
static_assert(std::is_aggregate_v<void>);
// expected-error@-1 {{static assertion failed due to requirement 'std::is_aggregate_v<void>'}} \
// expected-note@-1 {{'void' is not aggregate}} \
// expected-note@-1 {{because it is a cv void type}}


static_assert(!std::is_abstract<int>::value);

static_assert(std::is_abstract<int&>::value);
// expected-error-re@-1 {{static assertion failed due to requirement 'std::{{.*}}is_abstract<int &>::value'}} \
// expected-note@-1 {{'int &' is not abstract}} \
// expected-note@-1 {{because it is a reference type}} \
// expected-note@-1 {{because it is not a struct or class type}}

static_assert(std::is_abstract_v<int&>);
// expected-error@-1 {{static assertion failed due to requirement 'std::is_abstract_v<int &>'}} \
// expected-note@-1 {{'int &' is not abstract}} \
// expected-note@-1 {{because it is a reference type}} \
// expected-note@-1 {{because it is not a struct or class type}}


namespace test_namespace {
    using namespace std;
    static_assert(is_trivially_relocatable<int&>::value);
    // expected-error-re@-1 {{static assertion failed due to requirement '{{.*}}is_trivially_relocatable<int &>::value'}} \
    // expected-note@-1 {{'int &' is not trivially relocatable}} \
    // expected-note@-1 {{because it is a reference type}}
    static_assert(is_trivially_relocatable_v<int&>);
    // expected-error@-1 {{static assertion failed due to requirement 'is_trivially_relocatable_v<int &>'}} \
    // expected-note@-1 {{'int &' is not trivially relocatable}} \
    // expected-note@-1 {{because it is a reference type}}

    static_assert(is_trivially_copyable<int&>::value);
    // expected-error-re@-1 {{static assertion failed due to requirement '{{.*}}is_trivially_copyable<int &>::value'}} \
    // expected-note@-1 {{'int &' is not trivially copyable}} \
    // expected-note@-1 {{because it is a reference type}}
    static_assert(is_trivially_copyable_v<int&>);
    // expected-error@-1 {{static assertion failed due to requirement 'is_trivially_copyable_v<int &>'}} \
    // expected-note@-1 {{'int &' is not trivially copyable}} \
    // expected-note@-1 {{because it is a reference type}}

    static_assert(is_standard_layout<int&>::value);
     // expected-error-re@-1 {{static assertion failed due to requirement '{{.*}}is_standard_layout<int &>::value'}} \
     // expected-note@-1 {{'int &' is not standard-layout}} \
     // expected-note@-1 {{because it is a reference type}}

     static_assert(is_standard_layout_v<int&>);
     // expected-error@-1 {{static assertion failed due to requirement 'is_standard_layout_v<int &>'}} \
     // expected-note@-1 {{'int &' is not standard-layout}} \
     // expected-note@-1 {{because it is a reference type}}

    static_assert(is_assignable<int&, void>::value);
    // expected-error-re@-1 {{static assertion failed due to requirement '{{.*}}is_assignable<int &, void>::value'}} \
    // expected-error@-1 {{assigning to 'int' from incompatible type 'void'}}
    static_assert(is_assignable_v<int&, void>);
    // expected-error@-1 {{static assertion failed due to requirement 'is_assignable_v<int &, void>'}} \
    // expected-error@-1 {{assigning to 'int' from incompatible type 'void'}}

    static_assert(is_empty<int&>::value);
    // expected-error-re@-1 {{static assertion failed due to requirement '{{.*}}is_empty<int &>::value'}} \
    // expected-note@-1 {{'int &' is not empty}} \
    // expected-note@-1 {{because it is a reference type}} 
    static_assert(is_empty_v<int&>);
    // expected-error@-1 {{static assertion failed due to requirement 'is_empty_v<int &>'}} \
    // expected-note@-1 {{'int &' is not empty}} \
    // expected-note@-1 {{because it is a reference type}}

    static_assert(is_constructible<void>::value);
    // expected-error-re@-1 {{static assertion failed due to requirement '{{.*}}is_constructible<void>::value'}} \
    // expected-note@-1 {{because it is a cv void type}}
    static_assert(is_constructible_v<void>);
    // expected-error@-1 {{static assertion failed due to requirement 'is_constructible_v<void>'}} \
    // expected-note@-1 {{because it is a cv void type}}

    static_assert(std::is_aggregate<void>::value);
    // expected-error-re@-1 {{static assertion failed due to requirement 'std::{{.*}}is_aggregate<void>::value'}} \
    // expected-note@-1 {{'void' is not aggregate}} \
    // expected-note@-1 {{because it is a cv void type}}
    static_assert(std::is_aggregate_v<void>);
    // expected-error@-1 {{static assertion failed due to requirement 'std::is_aggregate_v<void>'}} \
    // expected-note@-1 {{'void' is not aggregate}} \
    // expected-note@-1 {{because it is a cv void type}}

    static_assert(is_final<int&>::value);
    // expected-error-re@-1 {{static assertion failed due to requirement '{{.*}}is_final<int &>::value'}} \
    // expected-note@-1 {{'int &' is not final}} \
    // expected-note@-1 {{because it is a reference type}} \
    // expected-note@-1 {{because it is not a class or union type}}

    static_assert(is_final_v<int&>);
    // expected-error@-1 {{static assertion failed due to requirement 'is_final_v<int &>'}} \
    // expected-note@-1 {{'int &' is not final}} \
    // expected-note@-1 {{because it is a reference type}} \
    // expected-note@-1 {{because it is not a class or union type}}

    using A = int[2];
    static_assert(is_final<A>::value);
    // expected-error-re@-1 {{static assertion failed due to requirement '{{.*}}is_final<int[2]>::value'}} \
    // expected-note@-1 {{'A' (aka 'int[2]') is not final}} \
    // expected-note@-1 {{because it is not a class or union type}}

    using Fn = void();
    static_assert(is_final<Fn>::value);
    // expected-error-re@-1 {{static assertion failed due to requirement '{{.*}}is_final<void ()>::value'}} \
    // expected-note@-1 {{'Fn' (aka 'void ()') is not final}} \
    // expected-note@-1 {{because it is a function type}} \
    // expected-note@-1 {{because it is not a class or union type}}

    static_assert(is_abstract<int&>::value);
    // expected-error-re@-1 {{static assertion failed due to requirement '{{.*}}is_abstract<int &>::value'}} \
    // expected-note@-1 {{'int &' is not abstract}} \
    // expected-note@-1 {{because it is a reference type}} \
    // expected-note@-1 {{because it is not a struct or class type}}

    static_assert(is_abstract_v<int&>);
    // expected-error@-1 {{static assertion failed due to requirement 'is_abstract_v<int &>'}} \
    // expected-note@-1 {{'int &' is not abstract}} \
    // expected-note@-1 {{because it is a reference type}} \
    // expected-note@-1 {{because it is not a struct or class type}}
}


namespace concepts {
template <typename T>
requires std::is_trivially_relocatable<T>::value void f();  // #cand1

template <typename T>
concept C = std::is_trivially_relocatable_v<T>; // #concept2

template <C T> void g();  // #cand2

template <typename T>
requires std::is_trivially_copyable<T>::value void f2();  // #cand3

template <typename T>
concept C2 = std::is_trivially_copyable_v<T>; // #concept4

template <C2 T> void g2();  // #cand4

template <typename T, typename U>
requires std::is_assignable<T, U>::value void f4();  // #cand7

template <typename T, typename U>
concept C4 = std::is_assignable_v<T, U>; // #concept8

template <C4<void> T> void g4();  // #cand8

template <typename... Args>
requires std::is_constructible<Args...>::value void f3();  // #cand5

template <typename... Args>
concept C3 = std::is_constructible_v<Args...>; // #concept6

template <C3 T> void g3();  // #cand6


template <typename T>
requires std::is_aggregate<T>::value void f5();  // #cand9

template <typename T>
concept C5 = std::is_aggregate_v<T>; // #concept10

template <C5 T> void g5();  // #cand10

void test() {
    f<int&>();
    // expected-error@-1 {{no matching function for call to 'f'}} \
    // expected-note@#cand1 {{candidate template ignored: constraints not satisfied [with T = int &]}} \
    // expected-note-re@#cand1 {{because '{{.*}}is_trivially_relocatable<int &>::value' evaluated to false}} \
    // expected-note@#cand1 {{'int &' is not trivially relocatable}} \
    // expected-note@#cand1 {{because it is a reference type}}

    g<int&>();
    // expected-error@-1 {{no matching function for call to 'g'}} \
    // expected-note@#cand2 {{candidate template ignored: constraints not satisfied [with T = int &]}} \
    // expected-note@#cand2 {{because 'int &' does not satisfy 'C'}} \
    // expected-note@#concept2 {{because 'std::is_trivially_relocatable_v<int &>' evaluated to false}} \
    // expected-note@#concept2 {{'int &' is not trivially relocatable}} \
    // expected-note@#concept2 {{because it is a reference type}}

    f2<int&>();
    // expected-error@-1 {{no matching function for call to 'f2'}} \
    // expected-note@#cand3 {{candidate template ignored: constraints not satisfied [with T = int &]}} \
    // expected-note-re@#cand3 {{because '{{.*}}is_trivially_copyable<int &>::value' evaluated to false}} \
    // expected-note@#cand3 {{'int &' is not trivially copyable}} \
    // expected-note@#cand3 {{because it is a reference type}}

    g2<int&>();
    // expected-error@-1 {{no matching function for call to 'g2'}} \
    // expected-note@#cand4 {{candidate template ignored: constraints not satisfied [with T = int &]}} \
    // expected-note@#cand4 {{because 'int &' does not satisfy 'C2'}} \
    // expected-note@#concept4 {{because 'std::is_trivially_copyable_v<int &>' evaluated to false}} \
    // expected-note@#concept4 {{'int &' is not trivially copyable}} \
    // expected-note@#concept4 {{because it is a reference type}}

    f4<int&, void>();
    // expected-error@-1 {{no matching function for call to 'f4'}} \
    // expected-note@#cand7 {{candidate template ignored: constraints not satisfied [with T = int &, U = void]}} \
    // expected-note-re@#cand7 {{because '{{.*}}is_assignable<int &, void>::value' evaluated to false}} \
    // expected-error@#cand7 {{assigning to 'int' from incompatible type 'void'}}

    g4<int&>();
    // expected-error@-1 {{no matching function for call to 'g4'}} \
    // expected-note@#cand8 {{candidate template ignored: constraints not satisfied [with T = int &]}} \
    // expected-note@#cand8 {{because 'C4<int &, void>' evaluated to false}} \
    // expected-note@#concept8 {{because 'std::is_assignable_v<int &, void>' evaluated to false}} \
    // expected-error@#concept8 {{assigning to 'int' from incompatible type 'void'}}

    f3<void>();
    // expected-error@-1 {{no matching function for call to 'f3'}} \
    // expected-note@#cand5 {{candidate template ignored: constraints not satisfied [with Args = <void>]}} \
    // expected-note-re@#cand5 {{because '{{.*}}is_constructible<void>::value' evaluated to false}} \
    // expected-note@#cand5 {{because it is a cv void type}}

    g3<void>();
    // expected-error@-1 {{no matching function for call to 'g3'}} \
    // expected-note@#cand6 {{candidate template ignored: constraints not satisfied [with T = void]}} \
    // expected-note@#cand6 {{because 'void' does not satisfy 'C3'}} \
    // expected-note@#concept6 {{because 'std::is_constructible_v<void>' evaluated to false}} \
    // expected-note@#concept6 {{because it is a cv void type}}

    f5<void>();
    // expected-error@-1 {{no matching function for call to 'f5'}} \
    // expected-note@#cand9 {{candidate template ignored: constraints not satisfied [with T = void]}} \
    // expected-note-re@#cand9 {{because '{{.*}}is_aggregate<void>::value' evaluated to false}} \
    // expected-note@#cand9 {{'void' is not aggregate}} \
    // expected-note@#cand9 {{because it is a cv void type}}

    g5<void>();
    // expected-error@-1 {{no matching function for call to 'g5'}} \
    // expected-note@#cand10 {{candidate template ignored: constraints not satisfied [with T = void]}} \
    // expected-note@#cand10 {{because 'void' does not satisfy 'C5'}} \
    // expected-note@#concept10 {{because 'std::is_aggregate_v<void>' evaluated to false}} \
    // expected-note@#concept10 {{'void' is not aggregate}} \
    // expected-note@#concept10 {{because it is a cv void type}}
}
}


namespace std {
template <typename T>
struct is_replaceable {
    static constexpr bool value = __builtin_is_replaceable(T);
};

template <typename T>
constexpr bool is_replaceable_v = __builtin_is_replaceable(T);

}

static_assert(std::is_replaceable<int&>::value);
// expected-error@-1 {{static assertion failed due to requirement 'std::is_replaceable<int &>::value'}} \
// expected-note@-1 {{'int &' is not replaceable}} \
// expected-note@-1 {{because it is a reference type}}
static_assert(std::is_replaceable_v<int&>);
// expected-error@-1 {{static assertion failed due to requirement 'std::is_replaceable_v<int &>'}} \
// expected-note@-1 {{'int &' is not replaceable}} \
// expected-note@-1 {{because it is a reference type}}