https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103831
Bug ID: 103831
Summary: views::lazy_split accepts Pattern as span<int, 1> when
V is input_range
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: hewillk at gmail dot com
Target Milestone: ---
This is an extremely strange case that I suspect is a language bug, consider:
#include <ranges>
#include <array>
#include <stream>
#include <span>
int main() {
auto ints = std::istringstream{"42"};
auto r = std::ranges::istream_view<int>(ints);
std::array<int, 1> arr{42};
std::span p{arr};
std::ranges::lazy_split_view s(r, p);
}
https://godbolt.org/z/o9EY9oPx6
In the above example, lazy_split_view should be rejected.
According to [range.lazy.split.view], when V does not model forward_range,
Pattern must be a tiny_range, however, span<int, 1> does not model tiny_range
since it does not have a static size function, so lazy_split_view should be
ill-formed.
I really don’t know why it will still be accepted.
