https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93267
--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:2a0f6c61b4db19535c632be68bddad74b6adb6cf commit r10-5985-g2a0f6c61b4db19535c632be68bddad74b6adb6cf Author: Jonathan Wakely <jwak...@redhat.com> Date: Wed Jan 15 14:09:35 2020 +0000 libstdc++: Fix weakly_incrementable to allow __int128 (PR 93267) The __iota_diff_t alias can be the type __int128, but that does not satisfy the signed_integral and __is_signed_integer_like concepts when __STRICT_ANSI__ is defined (which is true for -std=c++2a). Because weakly_incrementable is defined in terms of signed_integral, it is not satisfied by __int128, which means iota_view's iterator doesn't always satisfy input_or_output_iterator and so iota_view is not always a range. The solution is to define __max_size_type and __max_diff_type using __int128, so that __is_signed_integer_like allows __int128, and then make weakly_incrementable use __is_signed_integer_like instead of signed_integral. PR libstdc++/93267 * include/bits/iterator_concepts.h (__max_diff_type, __max_size_type): Move here from <bits/range_access.h> and define using __int128 when available. (__is_integer_like, __is_signed_integer_like): Move here from <bits/range_access.h>. (weakly_incrementable): Use __is_signed_integer_like. * include/bits/range_access.h (__max_diff_type, __max_size_type) (__is_integer_like, __is_signed_integer_like): Move to <bits/iterator_concepts.h>. (__make_unsigned_like_t): Move here from <ranges>. * include/std/ranges (__make_unsigned_like_t): Move to <bits/range_access.h>. (iota_view): Replace using-directive with using-declarations. * testsuite/std/ranges/iota/93267.cc: New test. * testsuite/std/ranges/iota_view.cc: Move to new 'iota' sub-directory.
