Checking if a type is void

[Paul Backus]

On Saturday, 28 May 2022 at 14:20:22 UTC, Stefan Koch wrote:
> The reason this is that internally a TypeExpression is created 
> and all Expressions defined a `!` operation.
> Because all of them are values/ do have init-expressions.

Reminds me of this example someone posted in the community 
Discord a while ago:

```d
alias T = int*;
alias U = typeof(*T);
static assert(is(U == int));
```