Diag

This crate implements error reporting for Hebi. In simple terms, it turns code + span + message into a nicely formatted error message:

error: mismatched type
> test.foo:1
| 
| let x: Foo = Bar {
|   a: 0,
|   ...
|   g: 0,
| };
| 
+ expected `Foo`, found `Bar`

It's actually completely agnostic to the target language, it operates on simple strings and spans.

There are many crates that implement something similar, for example:

• codespan
• annotate-snippets
• codemap
• language-reporting

And while they are all good at what they do, they all ended up having features I wouldn't use, and I wanted to keep the dependency graph as minimal as possible.