// RUN: %clang_cc1 -std=c++2a -verify %s -fcxx-exceptions
namespace std {
struct strong_ordering { // expected-note 6{{candidate}}
int n;
constexpr operator int() const { return n; }
static const strong_ordering less, equal, greater;
};
constexpr strong_ordering strong_ordering::less{-1},
strong_ordering::equal{0}, strong_ordering::greater{1};
struct weak_ordering {
int n;
constexpr weak_ordering(int n) : n(n) {}
constexpr weak_ordering(strong_ordering o) : n(o.n) {}
constexpr operator int() const { return n; }
static const weak_ordering less, equivalent, greater;
};
constexpr weak_ordering weak_ordering::less{-1},
weak_ordering::equivalent{0}, weak_ordering::greater{1};
struct partial_ordering {
double d;
constexpr partial_ordering(double d) : d(d) {}
constexpr partial_ordering(strong_ordering o) : d(o.n) {}
constexpr partial_ordering(weak_ordering o) : d(o.n) {}
constexpr operator double() const { return d; }
static const partial_ordering less, equivalent, greater, unordered;
};
constexpr partial_ordering partial_ordering::less{-1},
partial_ordering::equivalent{0}, partial_ordering::greater{1},
partial_ordering::unordered{__builtin_nan("")};
static_assert(!(partial_ordering::unordered < 0));
static_assert(!(partial_ordering::unordered == 0));
static_assert(!(partial_ordering::unordered > 0));
}
namespace Deletedness {
struct A {
std::strong_ordering operator<=>(const A&) const;
};
struct B {
bool operator==(const B&) const;
bool operator<(const B&) const;
};
struct C {
std::strong_ordering operator<=>(const C&) const = delete; // expected-note 2{{deleted}}
};
struct D1 {
bool operator==(const D1&) const;
std::strong_ordering operator<=>(int) const; // expected-note 2{{function not viable}} expected-note 2{{function (with reversed parameter order) not viable}}
bool operator<(int) const; // expected-note 2{{function not viable}}
};
struct D2 {
bool operator<(const D2&) const;
std::strong_ordering operator<=>(int) const; // expected-note 2{{function not viable}} expected-note 2{{function (with reversed parameter order) not viable}}
bool operator==(int) const; // expected-note 2{{function not viable}}
};
struct E {
bool operator==(const E&) const;
bool operator<(const E&) const = delete; // expected-note 2{{deleted}}
};
struct F {
std::strong_ordering operator<=>(const F&) const; // expected-note 2{{candidate}}
std::strong_ordering operator<=>(F) const; // expected-note 2{{candidate}}
};
struct G1 {
bool operator==(const G1&) const;
void operator<(const G1&) const;
};
struct G2 {
void operator==(const G2&) const;
bool operator<(const G2&) const;
};
struct H {
void operator<=>(const H&) const;
};
// expected-note@#base {{deleted comparison function for base class 'C'}}
// expected-note@#base {{no viable three-way comparison function for base class 'D1'}}
// expected-note@#base {{three-way comparison cannot be synthesized because there is no viable function for '<' comparison}}
// expected-note@#base {{no viable 'operator==' for base class 'D2'}}
// expected-note@#base {{three-way comparison cannot be synthesized because there is no viable function for '==' comparison}}
// expected-note@#base {{deleted comparison function for base class 'E'}}
// expected-note@#base {{implied comparison for base class 'F' is ambiguous}}
template<typename T> struct Cmp : T { // #base
std::strong_ordering operator<=>(const Cmp&) const = default; // #cmp expected-note 5{{here}}
};
void use(...);
void f() {
use(
Cmp<A>() <=> Cmp<A>(),
Cmp<B>() <=> Cmp<B>(),
Cmp<C>() <=> Cmp<C>(), // expected-error {{deleted}}
Cmp<D1>() <=> Cmp<D1>(), // expected-error {{deleted}}
Cmp<D2>() <=> Cmp<D2>(), // expected-error {{deleted}}
Cmp<E>() <=> Cmp<E>(), // expected-error {{deleted}}
Cmp<F>() <=> Cmp<F>(), // expected-error {{deleted}}
// FIXME: The following three errors are not very good.
// expected-error@#cmp {{value of type 'void' is not contextually convertible to 'bool'}}
Cmp<G1>() <=> Cmp<G1>(), // expected-note-re {{in defaulted three-way comparison operator for '{{.*}}Cmp<{{.*}}G1>' first required here}}j
// expected-error@#cmp {{value of type 'void' is not contextually convertible to 'bool'}}
Cmp<G2>() <=> Cmp<G2>(), // expected-note-re {{in defaulted three-way comparison operator for '{{.*}}Cmp<{{.*}}G2>' first required here}}j
// expected-error@#cmp {{no matching conversion for static_cast from 'void' to 'std::strong_ordering'}}
Cmp<H>() <=> Cmp<H>(), // expected-note-re {{in defaulted three-way comparison operator for '{{.*}}Cmp<{{.*}}H>' first required here}}j
0
);
}
// expected-note@#arr {{deleted comparison function for member 'arr'}}
// expected-note@#arr {{no viable three-way comparison function for member 'arr'}}
// expected-note@#arr {{three-way comparison cannot be synthesized because there is no viable function for '<' comparison}}
// expected-note@#arr {{no viable 'operator==' for member 'arr'}}
// expected-note@#arr {{three-way comparison cannot be synthesized because there is no viable function for '==' comparison}}
// expected-note@#arr {{deleted comparison function for member 'arr'}}
// expected-note@#arr {{implied comparison for member 'arr' is ambiguous}}
template<typename T> struct CmpArray {
T arr[3]; // #arr
std::strong_ordering operator<=>(const CmpArray&) const = default; // #cmparray expected-note 5{{here}}
};
void g() {
use(
CmpArray<A>() <=> CmpArray<A>(),
CmpArray<B>() <=> CmpArray<B>(),
CmpArray<C>() <=> CmpArray<C>(), // expected-error {{deleted}}
CmpArray<D1>() <=> CmpArray<D1>(), // expected-error {{deleted}}
CmpArray<D2>() <=> CmpArray<D2>(), // expected-error {{deleted}}
CmpArray<E>() <=> CmpArray<E>(), // expected-error {{deleted}}
CmpArray<F>() <=> CmpArray<F>(), // expected-error {{deleted}}
// FIXME: The following three errors are not very good.
// expected-error@#cmparray {{value of type 'void' is not contextually convertible to 'bool'}}
CmpArray<G1>() <=> CmpArray<G1>(), // expected-note-re {{in defaulted three-way comparison operator for '{{.*}}CmpArray<{{.*}}G1>' first required here}}j
// expected-error@#cmparray {{value of type 'void' is not contextually convertible to 'bool'}}
CmpArray<G2>() <=> CmpArray<G2>(), // expected-note-re {{in defaulted three-way comparison operator for '{{.*}}CmpArray<{{.*}}G2>' first required here}}j
// expected-error@#cmparray {{no matching conversion for static_cast from 'void' to 'std::strong_ordering'}}
CmpArray<H>() <=> CmpArray<H>(), // expected-note-re {{in defaulted three-way comparison operator for '{{.*}}CmpArray<{{.*}}H>' first required here}}j
0
);
}
}
namespace Access {
class A {
std::strong_ordering operator<=>(const A &) const; // expected-note {{here}}
public:
bool operator==(const A &) const;
bool operator<(const A &) const;
};
struct B {
A a; // expected-note {{would invoke a private 'operator<=>'}}
friend std::strong_ordering operator<=>(const B &, const B &) = default; // expected-warning {{deleted}} expected-note{{replace 'default'}}
};
class C {
std::strong_ordering operator<=>(const C &); // not viable (not const)
bool operator==(const C &) const; // expected-note {{here}}
bool operator<(const C &) const;
};
struct D {
C c; // expected-note {{would invoke a private 'operator=='}}
friend std::strong_ordering operator<=>(const D &, const D &) = default; // expected-warning {{deleted}} expected-note{{replace 'default'}}
};
}
namespace Synthesis {
enum Result { False, True, Mu };
constexpr bool toBool(Result R) {
if (R == Mu) throw "should not ask this question";
return R == True;
}
struct Val {
Result equal, less;
constexpr bool operator==(const Val&) const { return toBool(equal); }
constexpr bool operator<(const Val&) const { return toBool(less); }
};
template<typename T> struct Cmp {
Val val;
friend T operator<=>(const Cmp&, const Cmp&) = default; // expected-note {{deleted}}
};
template<typename T> constexpr auto cmp(Result equal, Result less = Mu, Result reverse_less = Mu) {
return Cmp<T>{equal, less} <=> Cmp<T>{Mu, reverse_less};
}
static_assert(cmp<std::strong_ordering>(True) == 0);
static_assert(cmp<std::strong_ordering>(False, True) < 0);
static_assert(cmp<std::strong_ordering>(False, False) > 0);
static_assert(cmp<std::weak_ordering>(True) == 0);
static_assert(cmp<std::weak_ordering>(False, True) < 0);
static_assert(cmp<std::weak_ordering>(False, False) > 0);
static_assert(cmp<std::partial_ordering>(True) == 0);
static_assert(cmp<std::partial_ordering>(False, True) < 0);
static_assert(cmp<std::partial_ordering>(False, False, True) > 0);
static_assert(!(cmp<std::partial_ordering>(False, False, False) > 0));
static_assert(!(cmp<std::partial_ordering>(False, False, False) == 0));
static_assert(!(cmp<std::partial_ordering>(False, False, False) < 0));
// No synthesis is performed for a custom return type, even if it can be
// converted from a standard ordering.
struct custom_ordering {
custom_ordering(std::strong_ordering o);
};
void f(Cmp<custom_ordering> c) {
c <=> c; // expected-error {{deleted}}
}
}
namespace Preference {
struct A {
A(const A&) = delete; // expected-note {{deleted}}
// "usable" candidate that can't actually be called
friend void operator<=>(A, A); // expected-note {{passing}}
// Callable candidates for synthesis not considered.
friend bool operator==(A, A);
friend bool operator<(A, A);
};
struct B {
B();
A a;
std::strong_ordering operator<=>(const B&) const = default; // expected-error {{call to deleted constructor of 'A'}}
};
bool x = B() < B(); // expected-note {{in defaulted three-way comparison operator for 'B' first required here}}
}
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