As outlined in this article
https://mpark.github.io/programming/2017/05/26/constexpr-function-parameters/,
C++ does not have constexpr parameters—we cannot use the arguments in a
constexpr function as constexpr variables. That rules out many valid
usages, and we had to use ugly hacks. Now we have consteval in C++20, and
consteval functions are supposed to be evaluated only at compile time, is
there any obstacle to regarding their parameters as constexpr?

Is there a real technical difficulty, or is it only that no one has
proposed it?

Best regards,

Yongwei

-- 
Yongwei Wu
URL: http://wyw.dcweb.cn/