Add lint for statics with explicit static lifetime.

[krk]

changelog: Add lint for statics with explicit static lifetime, fixes #4138.

[flip1995]

Please run util/dev update_lints

[oli-obk]

does anything speak against just extending the lint for constants to cover statics, too? https://rust-lang.github.io/rust-clippy/master/index.html#const_static_lifetime

[krk]

@flip1995 Running util/dev update_lints did not introduce any changes.

[flip1995]

Travis disagrees: https://travis-ci.com/rust-lang/rust-clippy/jobs/204695122#L1283

Not all lints defined properly. Please run `util/dev update_lints` to make sure all lints are defined properly.

CHANGELOG and README need updates.

But I agree with #4162 (comment). At least you should be able reuse the logic there?

[krk]

I have rebased and pushed, travis is green now, will try to reuse the logic.

[flip1995]

Thanks! Can you put the code of the lints into the same file (and into the same EarlyLintPass)? You can rename the file, if you want (If you do, please rename in a separate commit).

[flip1995]

You should also be able to use the Visitor provided by rustc: https://doc.rust-lang.org/nightly/nightly-rustc/syntax/visit/trait.Visitor.html?search=#method.visit_ty, instead of rewriting portions of it.

[krk]

You should also be able to use the Visitor provided by rustc: https://doc.rust-lang.org/nightly/nightly-rustc/syntax/visit/trait.Visitor.html?search=#method.visit_ty, instead of rewriting portions of it.

visit_type method in clippy_lints/src/const_static_lifetime.rs existed before this PR and I am reluctant to include changing it to the rustc visitor here.

[flip1995]

That's ok, you can use the existing function!

LGTM, just one NIT and this can get merged.

[flip1995]

Just realized, that you also renamed the lint and not only the file. That's fine IMO, but renaming a lint has two extra steps.

1. You have to register the renaming here:
   

   rust-clippy/clippy_lints/src/lib.rs

   Lines 1152 to 1156 in 7b2a7a2

   	pub fn register_renamed(ls: &mut rustc::lint::LintStore) {
   	ls.register_renamed("clippy::stutter", "clippy::module_name_repetitions");
   	ls.register_renamed("clippy::new_without_default_derive", "clippy::new_without_default");
   	ls.register_renamed("clippy::cyclomatic_complexity", "clippy::cognitive_complexity");
   	}

2. You have to add a test for the renamed lint here:
   https://github.com/rust-lang/rust-clippy/blob/master/tests/ui/rename.rs

Can you rename the lint to REDUNDANT_STATIC_LIFETIMES, that follows the naming conventions.

[flip1995]

Thanks!

@bors r+

[bors]

📌 Commit 38d5e71 has been approved by flip1995

[bors]

⌛ Testing commit 38d5e71 with merge a505984...

[flip1995]

@bors r+

[bors]

📌 Commit 7e07d1b has been approved by flip1995

[bors]

⌛ Testing commit 7e07d1b with merge 7a95c20...

[bors]

☀️ Test successful - checks-travis, status-appveyor
Approved by: flip1995
Pushing 7a95c20 to master...