Make empty_line_after_outer_attr an early lint

[phansch]

Fixes #5567

Unfortunately I couldn't find a way to reproduce the issue without syn/quote. Considering that most real-world macros use syn and/or quote, I think it's okay to pull them in anyway.

changelog: Fix false positive in [empty_line_after_outer_attr]

[flip1995]

We may have to be careful with the versions we use in syn and quote, so it is compatible with other tools of the rust-lang/rust repo?

[phansch]

We may have to be careful with the versions we use in syn and quote, so it is compatible with other tools of the rust-lang/rust repo?

For now I've specified the same versions as in rustc's Cargo.lock. I'm not sure how it will behave with the full feature though - it's required for the TraitItem and ItemTrait types.

[mati865]

Rust will override features with https://github.com/rust-lang/rust/blob/master/src/tools/rustc-workspace-hack/Cargo.toml
That means:

quote = { version = "1", features = ["default"] }
...
syn-1 = { package = "syn", version = "1", features = ['fold', 'full', 'extra-traits', 'visit'] }

[flip1995]

@phansch I think using just version = "1" would be better here, since the same is used in rustc-workspace-hack. After that r=me

[phansch]

@bors r=flip1995

[bors]

📌 Commit fd86b31 has been approved by flip1995

[bors]

⌛ Testing commit fd86b31 with merge 291385b...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: flip1995
Pushing 291385b to master...