Trait for "can be instantiated"?

[Salih Dincer]

On Tuesday, 10 May 2022 at 04:30:28 UTC, Ali Çehreli wrote:
> I just found something that looked like a workaround. I don't 
> know whether it is by design or by accident or whether this 
> exercise exposes a compiler or language bug. Sorry... :)

I can't exactly use the is(T == char) or is(T : char) check. It 
isn't happening! But I still have a little more patience :)

SDB at 79