Improved code with clippy

[41Leahcim]

I haven't used the bootstrapped compiler, but I think I have made some improvements using clippy. I have already made the following changes to the compiler:
Replaced self.first().is_digit(10) with self.first().is_ascii_digit() on lines 633, 664, and 680 of compiler/rust_lexer/src/lib.rs.

Removed unnecessary cast on line 262 of compiler/rustc_lexer/src/unescape.rs

Replaced ok_or_else with ok_or on line 303 of compiler/rustc_lexer/src/unescape.rs

Replaced !std::env::var("RUSTC_BOOTSTRAP").is_ok() with std::env::var("RUSTC_BOOTSTRAP").is_err() on line 4 of compiler/rustc_macros/build.rs

Removed needless borrow for generic argument envon line 53 of compiler/rust_llvm/build.rs

[rustbot]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @compiler-errors (or someone else) some time within the next two weeks.

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[rustbot]

Some changes occurred in src/tools/rustfmt

cc @rust-lang/rustfmt

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

[41Leahcim]

II have also changed some tooling code with clippy. I have made the following changes:
Turned the argument slice to an array on line 33 of src/tools/build_helper/src/ci.rs

Removed question mark operator on line 24 of src/tools/build_helper/src/git.rs

Removed a needless borrow implicitly performed by the compiler on line 147 of src/tools/clippy/declare_clippy_lint/src/lib.rs

Removed a needless borrow on line 54 of src/tools/miropt-test-tools/src/lib.rs

Replaced match expression with matches! macro on line 54 and 61 of src/tool/rustfmt/config_proc_macro/src/attrs.rs

Removed a needless borrow on lines 78 and 153 of src/tools/rustfmt/config_proc_macro/src/item_enum.rs

Replaced match expression with an equality check on line 16 of src/tools/rustfmt/config_proc_macro/src/utils.rs

Replaced argument slices to arrays on lines 43 and 51 of src/tools/rustfmt/build.rs

[ytmimi]

The rustfmt team prefers these kinds of changes be made directly to rustfmt instead of here in the rust-lang/rust repo.

[ytmimi]

Please revert these changes and open a PR directly to https://github.com/rust-lang/rustfmt for these kinds of changes.

[Noratrieb]

(where "these changes" means anything in clippy or rustfmt)

[ytmimi]

@41Leahcim to clarify, some of the tools in rust-lang/rust are developed in their own repos, and it's best to avoid making non essential, lint related changes here. Instead, prefer to open PRs directly to the respective repos.

Please revert all changes made to src/tools/rustfmt and src/tools/clippy

[41Leahcim]

Thanks for telling me. I'm pretty new to open source. That's why I'm still making stupid mistakes like this and why my pull request doesn't add anything special.

[41Leahcim]

I have reverted the changes to all tools. Only the changes to the compiler are left. With only 7 lines changed, it's a pretty much worthless pull request. So I would understand it if it won't get merged.

[fmease]

It's alright. I will approve it once you've squashed the commits into one.
r? fmease

[fmease]

Note that your two long comments describing the changes in prose are now outdated.
Friendly tip: No need to transliterate code changes to prose, paraphrasing and summarizing does the job a lot better.

[41Leahcim]

I have merged my commits

[fmease]

Thanks!

@bors r+ rollup

[bors]

📌 Commit 3c5e88c has been approved by fmease

It is now in the queue for this repository.