Halp! type system (__expand_field_0 error), compile time/runtime questions (AoC-2017 puzzle spoilers inside)

[aliak]

On Friday, 15 December 2017 at 01:43:04 UTC, Steven Schveighoffer 
wrote:
> So the CTFE interpreter doesn't like something to do with your 
> chain of ranges. This is not totally unexpected, as the CTFE 
> engine has lots of quirks that make it sometimes puke on valid 
> CTFE-able code.

:(

> At this time, I'd recommend doing your task at runtime anyway. 
> Hopefully I have shed some more light on how things are working 
> here.
>
> -Steve

Hah yeah, I'll have to switch to runtime for quite a few of the 
tasks. But yes you've explained everything! thanks a lot for 
taking the time :) I guess I'll report the issue with enumerate 
since maybe it's something that should be fixed eventually.