I just discovered an alternative use of the `in`-operator

[aberba]

On Friday, 7 August 2020 at 21:02:03 UTC, Per Nordlöw wrote:
> On Thursday, 6 August 2020 at 22:24:43 UTC, Paul Backus wrote:
>> [1] https://dlang.org/spec/expression.html#is_expression
>
> I bet there a several places in Phobos where this feature isn't 
> but could be used.

I feel same. That there's a clever use of certain D features 
waiting to be discovered.