I think we should maybe capture all failures if possible to output it nicer, because if the main task fails rustc outputs:

```
task '<main>' failed at 'Foo', test.rs:2
```

And it  also seems to exit with code 101.

That's not very nice in cases where the error is meant for the end user, having just `Foo` as output would be best IMO. Regarding the error code I guess it does not always matter.