`error-stack` UI tests fail under `nightly-2022-07-20`

[hashintel]

`error-stack` UI tests fail under `nightly-2022-07-20`

[indietyp]

To fix this, we could either

1. update the tests and CI (single PR) - because we already only compiletest on nightly
2. use rustversion to conditionally emit additional code on toolchains that are newer than 2022-07-20

(from the logs of #892 it also seems like the code to fetch the nightly toolchain version seems broken)

@TimDiekmann what do you think?

[TimDiekmann]

Thanks for filing this!

I think the easiest way is to simply bump the nightly version used in CI, this will also fix #898. I will do this tomorrow.

(from the logs of #892 it also seems like the code to fetch the nightly toolchain version seems broken)

Currently, it uses the first rust-toolchain.toml file it finds in the repository to determine the nightly version, this is why we currently try to keep the nightly versions on par between the different projects (package/engine, packages/libs/error-stack and packages/graph(on dev/graph) ). Probably there is a better way to this, but I haven't investigated this yet.

[indietyp]

What I specifically mean is the error:

Run nightly=$(cat $(find . -name rust-toolchain.toml) | grep channel | cut -d\" -f2)
parse error: Invalid literal at line 2, column 0
use toolchains: 

Which turns up in the CI.