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// RUN: %clang_cc1 -std=c++2a -verify %s
struct B {};
template<typename T = void>
bool operator<(const B&, const B&) = default; // expected-error {{comparison operator template cannot be defaulted}}
struct A {
friend bool operator==(const A&, const A&) = default;
friend bool operator!=(const A&, const B&) = default; // expected-error {{parameters for defaulted equality comparison operator must have the same type (found 'const A &' vs 'const B &')}}
friend bool operator!=(const B&, const B&) = default; // expected-error {{invalid parameter type for defaulted equality comparison}}
friend bool operator<(const A&, const A&);
friend bool operator<(const B&, const B&) = default; // expected-error {{invalid parameter type for defaulted relational comparison}}
friend bool operator>(A, A) = default; // expected-warning {{implicitly deleted}}
bool operator<(const A&) const;
bool operator<=(const A&) const = default;
bool operator==(const A&) const volatile && = default; // surprisingly, OK
bool operator<=>(const A&) = default; // expected-error {{defaulted member three-way comparison operator must be const-qualified}}
bool operator>=(const B&) const = default; // expected-error-re {{invalid parameter type for defaulted relational comparison operator; found 'const B &', expected 'const A &'{{$}}}}
static bool operator>(const B&) = default; // expected-error {{overloaded 'operator>' cannot be a static member function}}
friend bool operator>(A, const A&) = default; // expected-error {{must have the same type}} expected-note {{would be the best match}}
template<typename T = void>
friend bool operator==(const A&, const A&) = default; // expected-error {{comparison operator template cannot be defaulted}}
template<typename T = void>
bool operator==(const A&) const = default; // expected-error {{comparison operator template cannot be defaulted}}
};
template<typename T> struct Dependent {
using U = typename T::type;
bool operator==(U) const = default; // expected-error {{found 'Dependent<Bad>::U'}}
friend bool operator==(U, U) = default; // expected-error {{found 'Dependent<Bad>::U'}}
};
struct Good { using type = const Dependent<Good>&; };
template struct Dependent<Good>;
struct Bad { using type = Dependent<Bad>&; };
template struct Dependent<Bad>; // expected-note {{in instantiation of}}
namespace std {
struct strong_ordering {
int n;
constexpr operator int() const { return n; }
static const strong_ordering equal, greater, less;
};
constexpr strong_ordering strong_ordering::equal = {0};
constexpr strong_ordering strong_ordering::greater = {1};
constexpr strong_ordering strong_ordering::less = {-1};
}
namespace LookupContext {
struct A {};
namespace N {
template <typename T> auto f() {
bool operator==(const T &, const T &);
bool operator<(const T &, const T &);
struct B {
T a;
std::strong_ordering operator<=>(const B &) const = default;
};
return B();
}
auto g() {
struct Cmp { Cmp(std::strong_ordering); };
Cmp operator<=>(const A&, const A&);
bool operator!=(const Cmp&, int);
struct B {
A a;
Cmp operator<=>(const B &) const = default;
};
return B();
}
auto h() {
struct B;
bool operator==(const B&, const B&);
bool operator!=(const B&, const B&); // expected-note 2{{best match}}
std::strong_ordering operator<=>(const B&, const B&);
bool operator<(const B&, const B&); // expected-note 2{{best match}}
bool operator<=(const B&, const B&); // expected-note 2{{best match}}
bool operator>(const B&, const B&); // expected-note 2{{best match}}
bool operator>=(const B&, const B&); // expected-note 2{{best match}}
struct B {
bool operator!=(const B&) const = default; // expected-warning {{implicitly deleted}} expected-note {{deleted here}}
bool operator<(const B&) const = default; // expected-warning {{implicitly deleted}} expected-note {{deleted here}}
bool operator<=(const B&) const = default; // expected-warning {{implicitly deleted}} expected-note {{deleted here}}
bool operator>(const B&) const = default; // expected-warning {{implicitly deleted}} expected-note {{deleted here}}
bool operator>=(const B&) const = default; // expected-warning {{implicitly deleted}} expected-note {{deleted here}}
};
return B();
}
}
namespace M {
bool operator==(const A &, const A &) = delete;
bool operator<(const A &, const A &) = delete;
bool cmp = N::f<A>() < N::f<A>();
void operator<=>(const A &, const A &) = delete;
auto cmp2 = N::g() <=> N::g();
void use_h() {
N::h() != N::h(); // expected-error {{implicitly deleted}}
N::h() < N::h(); // expected-error {{implicitly deleted}}
N::h() <= N::h(); // expected-error {{implicitly deleted}}
N::h() > N::h(); // expected-error {{implicitly deleted}}
N::h() >= N::h(); // expected-error {{implicitly deleted}}
}
}
}
namespace evil1 {
template <class T> struct Bad {
// expected-error@+1{{found 'const float &'}}
bool operator==(T const &) const = default;
Bad(int = 0);
};
template <class T> struct Weird {
// expected-error@+1{{'float' cannot be used prior to '::'}}
bool operator==(typename T::Weird_ const &) const = default;
Weird(int = 0);
};
struct evil {
using Weird_ = Weird<evil>;
};
template struct Bad<float>; // expected-note{{evil1::Bad<float>' requested}}
template struct Weird<float>; // expected-note{{evil1::Weird<float>' requested}}
template struct Weird<evil>;
} // namespace evil1
namespace P1946 {
struct A {
friend bool operator==(A &, A &); // expected-note {{would lose const qualifier}}
};
struct B {
A a; // expected-note {{no viable three-way comparison}}
friend bool operator==(B, B) = default; // ok
friend bool operator==(const B&, const B&) = default; // expected-warning {{deleted}}
};
}
namespace p2085 {
// out-of-class defaulting
struct S1 {
bool operator==(S1 const &) const;
};
bool S1::operator==(S1 const &) const = default;
bool F1(S1 &s) {
return s != s;
}
struct S2 {
friend bool operator==(S2 const &, S2 const &);
};
bool operator==(S2 const &, S2 const &) = default;
bool F2(S2 &s) {
return s != s;
}
struct S3 {}; // expected-note{{here}}
bool operator==(S3 const &, S3 const &) = default; // expected-error{{not a friend}}
struct S4; // expected-note{{forward declaration}}
bool operator==(S4 const &, S4 const &) = default; // expected-error{{not a friend}}
struct S5; // expected-note 3{{forward declaration}}
bool operator==(S5, S5) = default; // expected-error{{not a friend}} expected-error 2{{has incomplete type}}
enum e {};
bool operator==(e, int) = default; // expected-error{{expected class or reference to a constant class}}
bool operator==(e *, int *) = default; // expected-error{{must have at least one}}
} // namespace p2085
namespace p2085_2 {
template <class T> struct S6 {
// expected-error@+2{{found 'const int &'}}
// expected-error@+1{{found 'const float &'}}
bool operator==(T const &) const;
};
template <class T> bool S6<T>::operator==(T const &) const = default;
template struct S6<int>; // expected-note{{S6<int>::operator==' requested}}
void f1() {
S6<float> a;
(void)(a == 0); // expected-note{{S6<float>::operator==' requested}}
}
template <class T> struct S7 {
// expected-error@+2{{'float' cannot be used}}
// expected-error@+1{{'int' cannot be used}}
bool operator==(typename T::S7_ const &) const;
S7(int = 0);
};
template <class T> bool S7<T>::operator==(typename T::S7_ const &) const = default;
struct evil {
using S7_ = S7<evil>;
};
template struct S7<float>; // expected-note{{S7<float>' requested}}
void f2() {
S7<int> a; // expected-note{{S7<int>' requested}}
S7<evil> b;
(void)(a == 0); // expected-error{{invalid operands}}
(void)(b == 0);
}
} // namespace p2085_2
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