[needless_return]: Remove all semicolons on suggestion

[dswij]

Closes #10182

Multiple semicolons currently breaks autofix for needless_return suggestions. Any semicolons left after removing return means that the return type will always be (), and thus fail to compile.

This PR allows needless_return to remove multiple semicolons.

The change won't cover the case where there is multiple line yet.

i.e.

fn needless_return() -> bool {
    return true;
;;
}

---

changelog: Sugg: [needless_return]: Now removes all semicolons on the same line
#10187

[rustbot]

r? @Jarcho

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[Jarcho]

It would be better to use the lexer here. Start at the end of the statement, skip all whitespace/comment tokens, and take the offset of all the leading semicolons. You should also bail out of the lint if a # is found (e.g. ; #[cfg(...)] {}).

[dswij]

I specifically avoided the lexer because it has a wide definition of whitespace, e.g. line feed also falls into whitespace.

I'm keeping this PR fairly simple so it won't cover those unnecessary colons spanning multiple lines. Also, rustc lint will fire for these redundant semicolons and rustfmt will fix this. This change is just to allow running clippy fix before all of that. I'd argue that even this scenario is fairly uncommon.

You should also bail out of the lint if a # is found (e.g. ; #[cfg(...)] {}).

Maybe, yeah. I think this is out of the scope of this PR, but unreachable_code will fire here, and the user should address that first before considering clippy lints.

I also tested this out and seems like needless_return is already bailing out for these scenarios.

[Jarcho]

Also, rustc lint will fire for these redundant semicolons and rustfmt will fix this.

That's reasonable then. Given that the issue had come up at all I was assuming this wasn't the case.

@bors r+

[bors]

📌 Commit d73adea has been approved by Jarcho

It is now in the queue for this repository.

[bors]

⌛ Testing commit d73adea with merge 07a7603...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: Jarcho
Pushing 07a7603 to master...