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Section: 220.127.116.11 [iterator.cust.move] Status: C++20 Submitter: Casey Carter Opened: 2019-07-29 Last modified: 2021-02-25
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The specification of the ranges::iter_move customization point in [iterator.cust.move] doesn't include a deleted poison pill overload. There is no std::iter_move to avoid, so such a poison pill is not needed. This is fine, except that it suggests that unqualified lookup for iter_move in the iter_move(E) expression in paragraph 1.1 should find declarations of iter_move in the global namespace via normal unqualified lookup, when the design intent is that only ADL be used to find overloads of iter_move.Absent a more idiomatic wording to specify an ADL-only lookup, we can correct the problem by specifying the lookup in paragraph 1.1 is performed in a context that includes the declaration "void iter_move();" which has the desired effect.
[2020-02 Status to Immediate on Thursday morning in Prague.]
This wording is relative to N4820.
[Drafting Note: There's a drive-by fix here to change "valid" — which suggests runtime behavior which cannot be validated at compile time — to "well-formed".]
Modify 18.104.22.168 [iterator.cust.move] as indicated:
-1- The name ranges::iter_move denotes a customization point object (22.214.171.124.6 [customization.point.object]). The expression ranges::iter_move(E) for some subexpression E is expression-equivalent to:
(1.1) — iter_move(E), if that expression is
valid, with overload resolution performed in a context that does not include a declaration of ranges::iter_move .