[iterator.cust.move] (original) (raw)

24 Iterators library [iterators]

24.3 Iterator requirements [iterator.requirements]

24.3.3 Customization point objects [iterator.cust]

24.3.3.1 ranges​::​iter_move [iterator.cust.move]

The expression ranges​::​iter_move(E) for a subexpression E is expression-equivalent to:

• iter_move(E), ifE has class or enumeration type anditer_move(E) is a well-formed expression when treated as an unevaluated operand, where the meaning of iter_move is established as-if by performing argument-dependent lookup only ([basic.lookup.argdep]).
• Otherwise, if the expression *E is well-formed:
  • if *E is an lvalue, std​::​move(*E);
  • otherwise, *E.
• Otherwise, ranges​::​iter_move(E) is ill-formed.
  [Note 1:
  This case can result in substitution failure when ranges​::​iter_move(E)appears in the immediate context of a template instantiation.
  — _end note_]

If ranges​::​iter_move(E) is not equal to *E, the program is ill-formed, no diagnostic required.