27 Iterators library [iterators]

27.5 Iterator adaptors [predef.iterators]

27.5.3 Move iterators [move.iterators]

27.5.3.3 move_­iterator operations [move.iter.ops]

27.5.3.3.6 move_­iterator​::​operator++ [move.iter.op.incr]

constexpr move_iterator& operator++();

constexpr move_iterator operator++(int);

move_iterator tmp = *this;
++current;
return tmp;