Update deps and switch to 2021 edition

[lwandrebeck]

cargo bootstrap and build run fine.
Update to 2021 edition.
Update to latest ucd-trie, serde, serde_json, thiserror.

[lwandrebeck]

Some errors do appear here: https://github.com/pest-parser/pest/actions/runs/3180773049/jobs/5184774281 even though test pass properly. Digging into it.

[tomtau]

lgtm; I tried to run cargo fix --edition https://doc.rust-lang.org/edition-guide/editions/transitioning-an-existing-project-to-a-new-edition.html and no files were changed, so this should be fine as it is.

The semver error looks like the one I mentioned in the third point here:
#705 (comment) because those reported violations on pest_meta look to be false positives.

[lwandrebeck]

@tomtau : I’ve ran it and got no change too. But, panic! is supposed not to be used as-is in 2021 edition. Maybe something slipped through the cracks between documentation and actual code ?

[NoahTheDuke]

I don't remember all of the details about editions; will this have any effects on MSRV?

[lwandrebeck]

1.56 brings 2021 edition, and we’re at 1.56.1 according to README.md
https://blog.rust-lang.org/2021/10/21/Rust-1.56.0.html

[NoahTheDuke]

Oh thanks for digging that out, excellent. Then yeah, this is good to go.

[tomtau]

There are some cases where the automated fixes are not applied: https://doc.rust-lang.org/edition-guide/editions/advanced-migrations.html#migrating-macros (macros, features, generated code, plus some fixes are optional, so it needs the --edition-idioms flag).
@lwandrebeck are you sure about the panic fix? My understanding of https://doc.rust-lang.org/edition-guide/rust-2021/panic-macro-consistency.html is that 2021 makes panic! usage to be consistent with println!, and that original line was consistent with it (hence there wasn't any automated fix)?

[tomtau]

For the context, previously MSVR was lower than 1.56, hence the edition was only up to 2018: #615 (comment) (but it was later increased to 1.56: #654 )

[lwandrebeck]

@tomtau : I’ve never put my hands at all into macros to be fair, so that’s out of my league. I’ve just re-run cargo fix --edition --edition-idioms --allow-dirty after putting back 2018 in Cargo.toml files without getting any change once again.
I’ll try to dig a bit more into that subject, but that won’t be until next day at best. If anyone is willing to check that point, go ahead :)