Can I add a deduction guide to `std` namespace?

问题

Suppose I want to make a new deduction guide making the following possible ?

std::string str;
std::basic_string_view sv = str;

Would that be an Ok customization ?

回答1:

[namespace.std]/2.4:

The behavior of a C++ program is undefined if it declares [...] a deduction guide for any standard library class template.

来源：https://stackoverflow.com/questions/58992794/can-i-add-a-deduction-guide-to-std-namespace