25 Iterators library [iterators]

25.5 Iterator adaptors [predef.iterators]

25.5.1 Reverse iterators [reverse.iterators]

25.5.1.3 Requirements [reverse.iter.requirements]

The template parameter Iterator shall either meet the requirements of a Cpp17BidirectionalIterator ([bidirectional.iterators]) or model bidirectional_­iterator ([iterator.concept.bidir]).
Additionally, Iterator shall either meet the requirements of a Cpp17RandomAccessIterator ([random.access.iterators]) or model random_­access_­iterator ([iterator.concept.random.access]) if the definitions of any of the members or the non-member operators ([reverse.iter.cmp]) are instantiated ([temp.inst]).