clang++ 10.0 fails with libstdc++ from gcc 10-20200216

[berolinux]

Bugzilla Link	44955
Resolution	FIXED
Resolved on	Feb 20, 2020 06:57
Version	10.0
OS	Linux
Blocks	#43900
CC	@efriedma-quic,@zmodem,@slacka,@zygoloid

Extended Description

Not 100% sure whether this is a libstdc++ bug or a clang bug. (Also filed a bug report against libstdc++ at https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93818).

Using libstdc++ from gcc 10-20200216 breaks using it with clang 10 in C++20 mode.

/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1329:17: error: missing 'typename' prior to dependent type name 'iterator_traits<iterator_t<_Vp> >::iterator_category'
using _Cat = iterator_traits<iterator_t<_Vp>>::iterator_category;
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1512:47: error: ambiguous deduction for template arguments of '_RangeAdaptor'
inline constexpr __adaptor::_RangeAdaptor filter
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1073:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1513:9)]
_RangeAdaptor(const _Callable& = {})
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1078:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1513:9)]
_RangeAdaptor(_Callable __callable)
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1552:19: error: missing 'typename' prior to dependent type name 'iterator_traits<iterator_t<_Base> >::iterator_category'
using _Cat = iterator_traits<iterator_t<_Base>>::iterator_category;
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1853:47: error: ambiguous deduction for template arguments of '_RangeAdaptor'
inline constexpr __adaptor::_RangeAdaptor transform
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1073:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1854:9)]
_RangeAdaptor(const _Callable& = {})
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1078:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1854:9)]
_RangeAdaptor(_Callable __callable)
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2000:47: error: ambiguous deduction for template arguments of '_RangeAdaptor'
inline constexpr __adaptor::_RangeAdaptor take
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1073:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2001:9)]
_RangeAdaptor(const _Callable& = {})
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1078:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2001:9)]
_RangeAdaptor(_Callable __callable)
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2092:47: error: ambiguous deduction for template arguments of '_RangeAdaptor'
inline constexpr __adaptor::_RangeAdaptor take_while
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1073:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2093:9)]
_RangeAdaptor(const _Callable& = {})
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1078:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2093:9)]
_RangeAdaptor(_Callable __callable)
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2169:47: error: ambiguous deduction for template arguments of '_RangeAdaptor'
inline constexpr __adaptor::_RangeAdaptor drop
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1073:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2170:9)]
_RangeAdaptor(const _Callable& = {})
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1078:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2170:9)]
_RangeAdaptor(_Callable __callable)
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2225:47: error: ambiguous deduction for template arguments of '_RangeAdaptor'
inline constexpr __adaptor::_RangeAdaptor drop_while
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1073:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2226:9)]
_RangeAdaptor(const _Callable& = {})
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1078:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2226:9)]
_RangeAdaptor(_Callable __callable)
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2297:10: error: missing 'typename' prior to dependent type name 'iterator_traits<iterator_t<_Base> >::iterator_category'
= iterator_traits<iterator_t<_Base>>::iterator_category;
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2299:10: error: missing 'typename' prior to dependent type name 'iterator_traits<iterator_t<range_reference_t<_Base> > >::iterator_category'
= iterator_traits<iterator_t<range_reference_t<_Base>>>
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2768:19: error: missing 'typename' prior to dependent type name 'iterator_traits<iterator_t<_Base> >::iterator_category'
using _Cat = iterator_traits<iterator_t<_Base>>::iterator_category;
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2942:47: error: ambiguous deduction for template arguments of '_RangeAdaptor'
inline constexpr __adaptor::_RangeAdaptor split
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1073:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2943:9)]
_RangeAdaptor(const _Callable& = {})
^
/usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:1078:2: note: candidate function [with _Callable = std::ranges::views::(lambda at /usr/bin/../lib64/gcc/x86_64-openmandriva-linux-gnu/10.0.0/../../../../include/c++/10.0.0/ranges:2943:9)]
_RangeAdaptor(_Callable __callable)
^
12 errors generated.

libstdc++ from gcc 10-20200209 works perfectly with both gcc and clang.

[zmodem]

+Richard maybe?

[zygoloid]

libstdc++ was relying on a C++20 feature we don't implement yet, and there's some disagreement between clang and gcc on a CTAD deduction too (but I don't think we know who is right yet). Both now fixed / worked around in libstdc++.

[zmodem]

libstdc++ was relying on a C++20 feature we don't implement yet, and there's
some disagreement between clang and gcc on a CTAD deduction too (but I don't
think we know who is right yet). Both now fixed / worked around in libstdc++.

Okay, sounds like this can be closed then. Thanks!