https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121143
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
That first loop corresponds to
struct __distance_fn final
{
template<typename _It, sentinel_for<_It> _Sent>
requires (!sized_sentinel_for<_Sent, _It>)
constexpr iter_difference_t<_It>
operator()[[nodiscard]](_It __first, _Sent __last) const
{
iter_difference_t<_It> __n = 0;
while (__first != __last)
{
++__first;
++__n;
}
return __n;
}
I think the caller is
if constexpr (ranges::forward_range<_Rg> || ranges::sized_range<_Rg>)
{
const auto __sz = ranges::distance(__rg);
if (__sz > (_Nm - size()))
__throw_bad_alloc();
ranges::uninitialized_copy_n(
ranges::begin(__rg), __sz,
data() + _M_size, unreachable_sentinel);
_M_size += size_type(__sz);
}
__throw_bad_alloc is indeed noreturn.
loop->nb_iterations is 8 (because that __n aka __sz is 9), but new_i_bound is
just 5.
