What are (were) the most difficult parts of D?

[Guillaume Piolat]

On Thursday, 12 May 2022 at 11:05:08 UTC, Basile B. wrote:
> - Certain variant forms of the `is` Expression are not obvious 
> (not intuitive), I'm pretty sure I still cant use them without 
> a quick look to the specs.

That one was a trouble to hear about => 
http://p0nce.github.io/d-idioms/#Get-parent-class-of-a-class-at-compile-time