Enums as type constraints?

[marwalsch]

There are plenty of issues on Stack Overflow regarding how System.Enum can/could be used as a type constraint, but I have found no discussion/solution on passing a certain enum as a type constraint. I stumbled across this by trying to implement the following:

    public class HttpStatusException<T> : Exception where T : HttpStatusCode
    { 
        //...
    }

This does currently not work, but could allow for constructs like the following:

try
{
   //...  
}catch(HttpStatusException<HttpStatusCode.Forbidden> ex)
{
   //...
}

I couldn't think about a lot of other use cases for this, but is this something feasible/desirable to implement?

[FiniteReality]

It would require runtime changes, which basically puts this at -1000 points, rather than the -100 points other changes would require. Which is unfortunate, because the more usable form of this - integer constants - would have lots of potential uses such as matrices or vectors which are implemented in a generic way regardless of the number of elements.

[marwalsch]

For those stumbling across this upon their search for a smooth solution for my initial problem, there is a when condition for catch blocks starting from C# 6.