Template specialisation for range of types

[ketmar via Digitalmars-d-learn]

Meta wrote:

> The reason this doesn't work is when you use ConstOf!U, it's not looking 
> for a `const U`, it's looking for the type `ConstOf!U`. I'm not sure if 
> this is a bug or not...

no, not a bug. this is the way type deconstruction works: it checks if your 
type was constructed with a given template.