https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107466
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-12 branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:d8def0b55572fc5bc02a0fee6a98787cd50ee885 commit r12-9485-gd8def0b55572fc5bc02a0fee6a98787cd50ee885 Author: Jonathan Wakely <jwak...@redhat.com> Date: Mon Nov 28 09:44:52 2022 +0000 libstdc++: Make 16-bit std::subtract_with_carry_engine work [PR107466] This implements the proposed resolution of LWG 3809, so that std::subtract_with_carry_engine can be used with a 16-bit result_type. Currently this produces a narrowing error when instantiating the std::linear_congruential_engine to create the initial state. It also truncates the default_seed constant when passing it as a result_type argument. Change the type of the constant to uint_least32_t and pass 0u when the default_seed should be used. libstdc++-v3/ChangeLog: PR libstdc++/107466 * include/bits/random.h (subtract_with_carry_engine): Use 32-bit type for default seed. Use 0u as default argument for subtract_with_carry_engine(result_type) constructor and seed(result_type) member function. * include/bits/random.tcc (subtract_with_carry_engine): Use 32-bit type for default seed and engine used for initial state. * testsuite/26_numerics/random/subtract_with_carry_engine/cons/lwg3809.cc: New test. (cherry picked from commit a64775a0edd46980036b757041f0c065ed9f8d22)