[libcxx-commits] [libcxx] [libc++][concepts] Implements concept helper `__libcpp_integer` (PR #78086)

[Hristo Hristov via libcxx-commits]

H-G-Hristov wrote:

@mordante @frederick-vs-ja This add `std::__libcpp_integer` concept. 

- Any ideas for an alternative name, e.g. 
  - `std::__libcpp_true_integer`
  - `std::__libcpp_integer_type`
- I have not replaced `__is_safe_integral_cmp` in this patch. I can do it in a follow-up patch.

https://github.com/llvm/llvm-project/pull/78086