https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115218
--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Patrick Palka <ppa...@gcc.gnu.org>: https://gcc.gnu.org/g:81c6c99efa6a7afd3082785a9ab7fb64d2c93e1d commit r15-7835-g81c6c99efa6a7afd3082785a9ab7fb64d2c93e1d Author: Patrick Palka <ppa...@redhat.com> Date: Wed Mar 5 11:11:35 2025 -0500 libstdc++: Some concat_view bugfixes [PR115215, PR115218, LWG 4082] - Use __builtin_unreachable to suppress a false-positive "control reaches end of non-void function" warning in the recursive lambda (which the existing tests failed to notice since test01 wasn't being called at runtime) - Relax the constraints on views::concat in the single-argument case as per PR115215 - Add an input_range requirement to that same case as per LWG 4082 - In the const-converting constructor of concat_view's iterator, don't require the first iterator to be default constructible PR libstdc++/115215 PR libstdc++/115218 libstdc++-v3/ChangeLog: * include/std/ranges (concat_view::iterator::_S_invoke_with_runtime_index): Use __builtin_unreachable in recursive lambda to certify it always exits via 'return'. (concat_view::iterator::iterator): In the const-converting constructor, direct initialize _M_it. (views::_Concat::operator()): Adjust constraints in the single-argument case as per LWG 4082. * testsuite/std/ranges/concat/1.cc (test01): Call it at runtime too. (test04): New test. Reviewed-by: Tomasz KamiÅski <tkami...@redhat.com> Reviewed-by: Jonathan Wakely <jwak...@redhat.com>
