std::experimental::ranges::CommonReference

Defined in header <experimental/ranges/concepts>
template < class T, class U > concept bool CommonReference =     Same< ranges::common_reference_t <T, U>, ranges::common_reference_t <U, T>> &&     ConvertibleTo<T, ranges::common_reference_t <T, U>> &&     ConvertibleTo<U, ranges::common_reference_t <T, U>> ;		(ranges TS)

The concept CommonReference<T, U> specifies that two types T and U share a common reference type (as computed by ranges::common_reference_t

CommonReference<T, U> is satisfied only if, given expressions t and u such that decltype((t)) is T and decltype((u)) is U

• ranges::common_reference_t <T, U> (t) is equal to ranges::common_reference_t <T, U> (t) if and only if t
• ranges::common_reference_t <T, U> (u) is equal to ranges::common_reference_t <T, U> (u) if and only if u

In other words, the conversion to the common reference type must not alter the equality-preservation property of the original expression.

Equality preservation

An expression is equality preserving if it results in equal outputs given equal inputs.

• The inputs to an expression consist of its operands.
• The outputs of an expression consist of its result and all operands modified by the expression (if any).

Every expression required to be equality preserving is further required to be stable

See also

common_reference	determine the common reference type of a set of types (class template)
Common	specifies that two types share a common type (concept)
common_type	determine the common type of a set of types (class template)