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* [Bug libstdc++/100567] New: views::take and views::drop should conditionally use _RangeAdaptor::operator() @ 2021-05-12 13:18 hewillk at gmail dot com 2021-05-12 17:58 ` [Bug libstdc++/100567] " ppalka at gcc dot gnu.org 2021-05-13 2:06 ` hewillk at gmail dot com 0 siblings, 2 replies; 3+ messages in thread From: hewillk at gmail dot com @ 2021-05-12 13:18 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100567 Bug ID: 100567 Summary: views::take and views::drop should conditionally use _RangeAdaptor::operator() Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: hewillk at gmail dot com Target Milestone: --- Hi, the re-implemented range adaptors use _RangeAdaptor to handle the arg of the adaptors, but for views::take and views::drop, the constraint that this arg can perfectly forward to range::range_difference_t<V> is lacking. https://godbolt.org/z/j88q5Yn6Y #include <ranges> struct S { operator int() { return 0; } }; const S obj; auto r = std::views::iota(0, 3); auto d1 = r | std::views::drop(obj); // ok, should error auto d2 = std::views::drop(r, obj); // error auto f1 = r | std::views::take(obj); // ok, should error auto f2 = std::views::take(r, obj); // error ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug libstdc++/100567] views::take and views::drop should conditionally use _RangeAdaptor::operator() 2021-05-12 13:18 [Bug libstdc++/100567] New: views::take and views::drop should conditionally use _RangeAdaptor::operator() hewillk at gmail dot com @ 2021-05-12 17:58 ` ppalka at gcc dot gnu.org 2021-05-13 2:06 ` hewillk at gmail dot com 1 sibling, 0 replies; 3+ messages in thread From: ppalka at gcc dot gnu.org @ 2021-05-12 17:58 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100567 Patrick Palka <ppalka at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |ppalka at gcc dot gnu.org --- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> --- Hmm, I believe we're behaving correctly according to wg21.link/p2281. This paper clarifies that partial application of a range adaptor stores the extra arguments in their decayed form, so in particular we discard their cv-qualifications. ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug libstdc++/100567] views::take and views::drop should conditionally use _RangeAdaptor::operator() 2021-05-12 13:18 [Bug libstdc++/100567] New: views::take and views::drop should conditionally use _RangeAdaptor::operator() hewillk at gmail dot com 2021-05-12 17:58 ` [Bug libstdc++/100567] " ppalka at gcc dot gnu.org @ 2021-05-13 2:06 ` hewillk at gmail dot com 1 sibling, 0 replies; 3+ messages in thread From: hewillk at gmail dot com @ 2021-05-13 2:06 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100567 康桓瑋 <hewillk at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |INVALID Status|UNCONFIRMED |RESOLVED --- Comment #2 from 康桓瑋 <hewillk at gmail dot com> --- (In reply to Patrick Palka from comment #1) > Hmm, I believe we're behaving correctly according to wg21.link/p2281. This > paper clarifies that partial application of a range adaptor stores the extra > arguments in their decayed form, so in particular we discard their > cv-qualifications. Oops, you are right. Tim made a big change to the range adaptor objects in P2281. Thank you for correcting me. ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-05-13 2:06 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-05-12 13:18 [Bug libstdc++/100567] New: views::take and views::drop should conditionally use _RangeAdaptor::operator() hewillk at gmail dot com 2021-05-12 17:58 ` [Bug libstdc++/100567] " ppalka at gcc dot gnu.org 2021-05-13 2:06 ` hewillk at gmail dot com
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