https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90102
--- Comment #6 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:eca833b81289438ec5ae3ed4c77ffb49cfb65f34 commit r11-832-geca833b81289438ec5ae3ed4c77ffb49cfb65f34 Author: Jonathan Wakely <jwak...@redhat.com> Date: Tue Jun 2 18:13:08 2020 +0100 libstdc++: Make debug containers prefer copy ctor to base ctor (PR 90102) When given a type which can convert to any container-like type, the C(const C&) copy constructor and C(const C::_Base&) converting constructor are ambiguous. This change replaces the converting constructor's parameter with a reference_wrapper-like type so that calling that constructor requires an additional user-defined conversion. This gives it a lower rank than the copy constructor, avoiding the ambiguity. While testing this change I discovered that __gnu_debug::forward_list doesn't have a convering constructor from the std::forward_list base, so this adds it. We should probably consider whether the converting constructors should be 'explicit' but I'm not changing that now. libstdc++-v3/ChangeLog: PR libstdc++/90102 * include/debug/deque (deque(const _Base&)): Replace parameter with a struct that wraps a const _Base&. * include/debug/forward_list (forward_list(_Base_ref)): New constructor. * include/debug/list (list(const _Base&)): Replace parameter with a struct that wraps a const _Base&. * include/debug/map.h (map(const _Base&)): Likewise. * include/debug/multimap.h (multimap(const _Base&)): Likewise. * include/debug/multiset.h (multiset(const _Base&)): Likewise. * include/debug/set.h (set(const _Base&)): Likewise. * include/debug/unordered_map (unordered_map(const _Base&)) (unordered_multimap(const _Base&)): Likewise. * include/debug/unordered_set (unordered_set(const _Base&)) (unordered_multiset(const _Base&)): Likewise. * testsuite/23_containers/vector/cons/destructible_debug_neg.cc: Adjust dg-error line number. * include/debug/vector (vector(const _Base&)): Likewise. * testsuite/23_containers/deque/debug/90102.cc: New test. * testsuite/23_containers/forward_list/debug/90102.cc: New test. * testsuite/23_containers/list/debug/90102.cc: New test. * testsuite/23_containers/map/debug/90102.cc: New test. * testsuite/23_containers/multimap/debug/90102.cc: New test. * testsuite/23_containers/multiset/debug/90102.cc: New test. * testsuite/23_containers/set/debug/90102.cc: New test. * testsuite/23_containers/unordered_map/debug/90102.cc: New test. * testsuite/23_containers/unordered_multimap/debug/90102.cc: New test. * testsuite/23_containers/unordered_multiset/debug/90102.cc: New test. * testsuite/23_containers/unordered_set/debug/90102.cc: New test. * testsuite/23_containers/vector/debug/90102.cc: New test.
