gcc/libstdc++-v3/include
Jonathan Wakely 6c2582c040 libstdc++: Fix view adaptors for mixed-const sentinels and iterators (PR 95322)
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.
2020-05-27 22:08:15 +01:00
..
backward Update copyright years. 2020-01-01 12:51:42 +01:00
bits libstdc++: Fix std::reverse_iterator comparisons (PR 94354) 2020-05-27 21:58:56 +01:00
c Update copyright years. 2020-01-01 12:51:42 +01:00
c_compatibility Update copyright years. 2020-01-01 12:51:42 +01:00
c_global Update copyright years. 2020-01-01 12:51:42 +01:00
c_std Update copyright years. 2020-01-01 12:51:42 +01:00
debug libstdc++: Fix function that can't be constexpr in C++11 (PR 95289) 2020-05-23 18:27:35 +01:00
decimal Update copyright years. 2020-01-01 12:51:42 +01:00
experimental libstdc++: Refactor filesystem::path string conversions 2020-05-23 09:40:16 +01:00
ext libstdc++: Avoid errors in allocator's noexcept-specifier (PR 89510) 2020-04-30 16:01:43 +01:00
parallel libstdc++: Fix some C++20 algorithms to work in parallel mode 2020-05-07 21:43:49 +01:00
precompiled Update copyright years. 2020-01-01 12:51:42 +01:00
pstl Restore enable_if lost during original import of pstl 2019-12-11 03:38:24 +00:00
std libstdc++: Fix view adaptors for mixed-const sentinels and iterators (PR 95322) 2020-05-27 22:08:15 +01:00
tr1 Update copyright years. 2020-01-01 12:51:42 +01:00
tr2 Update copyright years. 2020-01-01 12:51:42 +01:00
Makefile.am libstdc++: Add lightweight replacement for std::numeric_limits (PR 92546) 2020-02-17 15:11:04 +00:00
Makefile.in libstdc++: Add lightweight replacement for std::numeric_limits (PR 92546) 2020-02-17 15:11:04 +00:00