This page is a snapshot from the LWG issues list, see the Library Active Issues List for more information and the meaning of C++20 status.
3292.iota_view is under-constrained
Section: 25.6.4.2 [range.iota.view] Status: C++20 Submitter: Barry Revzin Opened: 2019-09-13 Last modified: 2021-02-25
Priority: Not Prioritized
View all other issues in [range.iota.view].
View all issues with C++20 status.
Discussion:
P1207R4 changed weakly_incrementable from requiring semiregular to requiring default_constructible && movable.
iota_view currently is specified to require that W be just weakly_incrementable. But we have to copy the W from the view into its iterator and also in operator*() to return a W. The shortest resolution is just to add " && semiregular<W>" to the class constraints.
[Status to ready after discussion Friday morning in Belfast]
Proposed resolution:
This wording is relative to N4830.
Modify 25.6.4.2 [range.iota.view] as indicated:
namespace std::ranges {
[…]
template<weakly_incrementable W, semiregular Bound = unreachable_sentinel_t>
requires weakly-equality-comparable-with<W, Bound> && semiregular<W>
class iota_view : public view_interface<iota_view<W, Bound> {
[…]
};
[…]
}
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4