What is your favorite D feature? [Call for snippets]

[Seb via Digitalmars-d]

On Thursday, 22 June 2017 at 01:00:42 UTC, Mike wrote:
> Beginning with most favorite:
>  - CTFE
>  - static if - If you don't consider that part of CTFE
>  - Template Mixins
>  - Templates - Pretty much goes along with the top 2
>  - String Mixins
>  - Unit Tests
>
> DIP1000 may make that list too, if I ever get around to trying 
> it out.

Nice list, but I was actually looking for more concise, 
actionable snippets or idea(s) for such.
I should have made this clearer. Sorry.
For some I have already submitted PRs - the other are still 
missing a good "WoW" snippet. Ideas?

>  - CTFE

-> https://github.com/dlang/dlang.org/pull/1758


>  - static if - If you don't consider that part of CTFE

Do you know a more concise example than my commonPrefix one from 
the Tour?
https://tour.dlang.org/tour/en/gems/traits

>  - Template Mixins
TBD
>  - Templates - Pretty much goes along with the top 2
TBD
>  - String Mixins

-> https://github.com/dlang/dlang.org/pull/1762

>  - Unit Tests
TBD