6c2582c040
The bug report is that transform_view's sentinel<false> cannot be compared to its iterator<true>. The comparison is supposed to use operator==(iterator<Const>, sentinel<Const>) after converting sentinel<false> to sentinel<true>. However, the operator== is a hidden friend so is not a candidate when comparing iterator<true> with sentinel<false>. The required conversion would only happen if we'd found the operator, but we can't find the operator until after the conversion happens. A new LWG issue has been reported, but not yet assigned a number. The solution suggested by Casey Carter is to make the hidden friends of the sentinel types work with iterators of any const-ness, so that no conversions are required. Patrick Palka observed that join_view has a similar problem and a similar fix is used for its sentinel. PR libstdc++/95322 * include/std/ranges (transform_view::_Sentinel): Allow hidden friends to work with _Iterator<true> and _Iterator<false>. (join_view::_Sentinel): Likewise. * testsuite/std/ranges/adaptors/95322.cc: New test. |
||
|---|---|---|
| .. | ||
| concepts | ||
| ranges | ||
| time | ||