在 C++，如何将模板参数强制为范围枚举值类型？

Question

I have a class template that I'd like to write as follows:

template </*what to put here?*/ T>
Class Bar {};

I would like to enforce T to only be a value from a scoped enum. I used the is_scoped_enum type check provided here , however the best I was able to come up with was to change Bar to be like this:

template <typename T>
concept ScopeEnum = is_scoped_enum<T>::value;

template<ScopeEnum SE, SE se>
class Bar {};

How can I implement it so Bar remains as intended?

Answer 1

Use a generic non-type parameter, and constrain its declaration

template <ScopedEnum auto se>
class Bar {};