My late christmas present for you: context-aware assertion error messages

[Atila Neves]

On Saturday, 12 January 2019 at 15:34:02 UTC, Seb wrote:
> tl;dr: I was annoyed for years that D's assert are so non 
> informative AssertError, so here's my late Christmas present 
> for the D community. With 2.085 DMD will gain an experimental 
> flag for more informative assertion errors. Feedback on this 
> experimental feature is welcome, s.t. we eventually can enable 
> it by default.
>
> [...]

Awesome.

It's obvious that assertions for equality are the most common, I 
wonder how easy it would be to get other changes merged like 
`assert(foo in bar)`. There are also all the assertions that make 
use of `equal` because of ranges. In unit-threaded `foo.should == 
bar` works if foo is a range and bar is a dynamic array.

What I'd really like is access to the AST in the assert but alas 
I don't think that will ever be possible.