If I understand correctly the other comments, they just say it's possible to do in c++ with templates/operator overloading/constexpr. It's not an existing type of the standard library. This type could work in simple situations but will probably not be as good as a native type in more complex situations.

It's a hypothetical. The actual `in_range` template function doesn't work like that at all and would be annoying to use for this if you tried (it returns true/false so you have to wrap all operations in a conditional). jcelerier is suggesting we'd have something like:

  template<typename T, int min, int max> // probably not int for min/max, but whatever
  class in_range {
    ...
  };

which would be instantiated with `using <my_type_name> = ...;` and would have all the necessary operator overloads and checks. Still, it's only bringing in the runtime, not compile time, checks and can't be "turned off" (well, maybe take a fourth boolean value and have two code paths everywhere that can be optimized down to one if you want to turn off the checks) like it can in Ada (whether that's a good idea or not depends on how well you've proved out your code). It's also introducing all the overhead of an object which isn't necessary in Ada.