Yes, constraints can have helpful error messages!

[Atila Neves]

On Saturday, 9 April 2022 at 01:03:32 UTC, Marvin Hannott wrote:
> I was a bit surprised, reading the discussions about how 
> constraints aren't very helpful when it comes to figuring out 
> what is wrong. And I was even more surprised that of all things 
> `pragma` was called to the rescue. But isn't there a much 
> better, simpler way?
>
> [...]

Have you looked at https://github.com/atilaneves/concepts ?