Issue 3530: BUILTIN-PTR-MEOW should not opt the type out of syntactic checks (original) (raw)

-1- In this subclause, _BUILTIN-PTR-CMP_(T, op, U)for types T and U and where op is an equality (7.6.10 [expr.eq]) or relational operator (7.6.9 [expr.rel]) is a boolean constant expression._BUILTIN-PTR-CMP_(T, op, U)is true if and only if op in the expressiondeclval<T>() op declval<U>()resolves to a built-in operator comparing pointers.

struct ranges::equal_to { template<class T, class U> requires equality_comparable_with<T, U> || BUILTIN-PTR-CMP(T, ==, U) constexpr bool operator()(T&& t, U&& u) const;

using is_transparent = unspecified; };

template<class T, class U> requires equality_comparable_with<T, U> || BUILTIN-PTR-CMP(T, ==, U) constexpr bool operator()(T&& t, U&& u) const;

-?- Constraints: T and U satisfy equality_comparable_with.

-2- Preconditions: If the expressionstd​::​forward<T>(t) == std​::​forward<U>(u) results in a call to a built-in operator == comparing pointers of type P, the conversion sequences from both T and U to P are equality-preserving (18.2 [concepts.equality]); otherwise, T and Umodel equality_comparable_with.

-3- Effects:

1. (3.1) — If the expression std​::​forward<T>(t) == std​::​forward<U>(u)results in a call to a built-in operator == comparing pointers of type P, returns false if either (the converted value of) t precedes u or uprecedes t in the implementation-defined strict total order over pointers (3.28 [defns.order.ptr]) and otherwise true.
2. (3.2) — Otherwise, equivalent to: return std​::​forward<T>(t) == std​::​forward<U>(u);

struct ranges::not_equal_to { template<class T, class U> requires equality_comparable_with<T, U> || BUILTIN-PTR-CMP(T, ==, U) constexpr bool operator()(T&& t, U&& u) const;

using is_transparent = _unspecified_;

};

template<class T, class U> constexpr bool operator()(T&& t, U&& u) const;

-?- Constraints: T and U satisfy equality_comparable_with.

-4- operator() has effects eEffects: Equivalent to:

return !ranges::equal_to{}(std::forward(t), std::forward(u));

struct ranges::greater { template<class T, class U> requires totally_ordered_with<T, U> || BUILTIN-PTR-CMP(T, <, U) constexpr bool operator()(T&& t, U&& u) const;

using is_transparent = unspecified; };

template<class T, class U> constexpr bool operator()(T&& t, U&& u) const;

-?- Constraints: T and U satisfy totally_ordered_with.

-5- operator() has effects eEffects: Equivalent to:

return ranges::less{}(std::forward(u), std::forward(t));

struct ranges::less { template<class T, class U> requires totally_ordered_with<T, U> || BUILTIN-PTR-CMP(T, <, U) constexpr bool operator()(T&& t, U&& u) const;

using is_transparent = unspecified; };

template<class T, class U> requires totally_ordered_with<T, U> || BUILTIN-PTR-CMP(T, <, U) constexpr bool operator()(T&& t, U&& u) const;

-?- Constraints: T and U satisfy totally_ordered_with.

-6- Preconditions: If the expressionstd​::​forward<T>(t) < std​::​forward<U>(u) results in a call to a built-in operator < comparing pointers of type P, the conversion sequences from both T and U to P are equality-preserving (18.2 [concepts.equality]); otherwise, T and Umodel totally_ordered_with. For any expressions ET and EU such that decltype((ET)) is T anddecltype((EU)) is U, exactly one of ranges::less{}(ET, EU), ranges::less{}(EU, ET), or ranges::equal_to{}(ET, EU) is true.

-7- Effects:

1. (7.1) — If the expression std​::​forward<T>(t) < std​::​forward<U>(u)results in a call to a built-in operator < comparing pointers of type P, returns true if (the converted value of) t precedes u in the implementation-defined strict total order over pointers (3.28 [defns.order.ptr]) and otherwise false.
2. (7.2) — Otherwise, equivalent to: return std​::​forward<T>(t) < std​::​forward<U>(u);

struct ranges::greater_equal { template<class T, class U> requires totally_ordered_with<T, U> || BUILTIN-PTR-CMP(T, <, U) constexpr bool operator()(T&& t, U&& u) const;

using is_transparent = unspecified; };

template<class T, class U> constexpr bool operator()(T&& t, U&& u) const;

-?- Constraints: T and U satisfy totally_ordered_with.

-8- operator() has effects eEffects: Equivalent to:

return !ranges::less{}(std::forward(t), std::forward(u));

struct ranges::less_equal { template<class T, class U> requires totally_ordered_with<T, U> || BUILTIN-PTR-CMP(T, <, U) constexpr bool operator()(T&& t, U&& u) const;

using is_transparent = unspecified; };

template<class T, class U> constexpr bool operator()(T&& t, U&& u) const;

-?- Constraints: T and U satisfy totally_ordered_with.

-9- operator() has effects eEffects: Equivalent to:

return !ranges::less{}(std::forward(u), std::forward(t));