Allocators are only required to be explicitly convertible between different types. `shared_ptr` currently requires implicit conversions, however. This is a regression introduced by #200401.
libcxx/test/support
copy_move_types.h
<map>
std::map
cend()
MinSequenceContainer
nasty_char_traits::to_char_type
expected
[[nodiscard]]
views::zip_transform
views::enumerate