Honor avoid-breaking-exported-api in needless_pass_by_ref_mut

[flip1995]

Until now, the lint only emitted a warning, when breaking public API. Now it doesn't lint at all when the config value is not set to false, bringing it in line with the other lints using this config value.

Also ensures that this config value is documented in the lint.

changelog: none
(I don't think a changelog is necessary, since this lint is in nursery)

---

Fixes #11374

cc @GuillaumeGomez

Marking as draft: Does this lint even break public API? If I change a function signature from fn foo(x: &mut T) to fn foo(x: &T), I can still call it with foo(&mut x). The only "breaking" thing is that the clippy::unnecessary_mut_passed lint will complain that &mut at the callsite is not necessary, possibly trickling down to the crate user having to remote a mut from a variable. Playground.

Are there examples where this actually breaks public API, that I'm missing?

[rustbot]

r? @Centri3

(rustbot has picked a reviewer for you, use r? to override)

[GuillaumeGomez]

Marking as draft: Does this lint even break public API? If I change a function signature from fn foo(x: &mut T) to fn foo(x: &T), I can still call it with foo(&mut x). The only "breaking" thing is that the clippy::unnecessary_mut_passed lint will complain that &mut at the callsite is not necessary, possibly trickling down to the crate user having to remote a mut from a variable. Playground.

Are there examples where this actually breaks public API, that I'm missing?

That's actually a good question... The API changed, so I suppose it's breaking semver but it doesn't break it for the API users. Interesting.

[Centri3]

The function will no longer be FnMut but Fn, or smth like that, so it can break API. It's probably pretty rare though and this is why I was in favor of linting anyway

Don't have any examples of this but it's probably possible when passing the function to some iterator methods, like map or filter.

[flip1995]

The function will no longer be FnMut but Fn

Huh, isn't this only about what the function captures? But I think you're hinting to the right thing: You won't be able to pass the function as an argument to another function, expecting a Fn/FnOnce/FnMut with a &mut argument, instead of a & argument: Playground

I will run lintcheck for this lint (modified to ONLY lint public items). Let's look at some data.

[flip1995]

So lintcheck gave some interesting discoveries: Passing the function is only a semi-issue: You can work around that by doing something like bar(|x| foo(x)) instead of bar(foo). But that makes the code on the callsite longer. The h2 crate has an almost-use-case for this together with the futures_util::poll_fn.

Further than that, the lock_api crated showed where the &mut has a different purpose than just the mutability: To ensure that only a single reference exists at the time of calling some of the functions.

Here are the results:

clippy 0.1.75 (5ec94d2043a 2023-10-09)

Reports

target/lintcheck/sources/h2-0.3.21/src/client.rs:1431:13 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.3.21/src/share.rs:422:37 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/mutex.rs:558:30 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/mutex.rs:611:35 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/mutex.rs:629:20 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/remutex.rs:678:30 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/remutex.rs:722:35 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/remutex.rs:740:20 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/rwlock.rs:1255:30 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/rwlock.rs:1297:35 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/rwlock.rs:1315:20 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/rwlock.rs:1545:30 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/rwlock.rs:1629:35 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/rwlock.rs:1647:20 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/rwlock.rs:1890:30 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/rwlock.rs:1964:35 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lock_api-0.4.10/src/rwlock.rs:1982:20 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/nom-7.1.3/src/multi/mod.rs:625:40 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/parking_lot-0.12.1/src/condvar.rs:255:48 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/parking_lot-0.12.1/src/condvar.rs:285:22 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/parking_lot-0.12.1/src/condvar.rs:381:22 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/socket2-0.5.4/src/lib.rs:683:38 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/want-0.3.1/src/lib.rs:192:37 clippy::needless_pass_by_ref_mut "this argument is a mutable reference, but not used mutably"

Stats:

lint	count
clippy::needless_pass_by_ref_mut	23

---

In conclusion, I would say that we don't want to break public API, because passing a function with &mut arguments is definitely a use case. Also the shared-unique vs immutable-mutable difference probably matters more on public API than private API, even though I see this as another big issue, where it might even be impossible for Clippy to tell when what the intention behind the &mut is. But we can work around this with applicability, lint group and a note on the lint emission.

[Centri3]

I'm not sure whether that's actually possible by just changing the signature, since yeah that is based on what it captures. It might just be that any function implements Fn + FnMut + FnOnce no matter what.

What you showed is a larger concern though which I forgot about and is already checked for by the lint for cases of this in the current crate. This might be rare enough that we can just always give a note on public items, I can't really think of any non-contrived example where somebody passes a function pointer to smth expecting Fn with those specific parameters (rather than T). Also a mutable reference to one of those parameters.

[flip1995]

is already checked for by the lint for cases of this in the current crate.

Ah right, I forgot about that. This is good, but on public items we can't tell. So we should definitely emit a warning there, document it in the lint documentation and apply the exported API config correctly IMO.

I can't really think of any non-contrived example where somebody passes a function pointer to smth expecting Fn with those specific parameters

See my comment above with an example from the futures_util crate.

[Centri3]

Further than that, the lock_api crated showed where the &mut has a different purpose than just the mutability: To ensure that only a single reference exists at the time of calling some of the functions.

This would not be linted as it has an unsafe block. #11624

If it's passed to another function that's both "safe" and takes &, that's unsound, even if it's encapsulated. So I think this is a non-issue. If there's no unsafe it's safe to assume exclusivity is unnecessary

[flip1995]

So I think this is a non-issue. If there's no unsafe it's safe to assume exclusivity is unnecessary

You are way ahead of me :D You're right.

[flip1995]

I'll add the warning and documentation about this in this PR and then mark it as ready for review some time this week. (I'll be at EuroRust, where I might get some time for this and other Clippy TODOs I still have)

[GuillaumeGomez]

For the unsafe fn/block, we still need to wait for #11624 to be merged.

PS: I'll be at eurorust too. :D

[bors]

☔ The latest upstream changes (presumably #11622) made this pull request unmergeable. Please resolve the merge conflicts.

[flip1995]

@Centri3 rebased and ready for final review.

[bors]

☔ The latest upstream changes (presumably #11685) made this pull request unmergeable. Please resolve the merge conflicts.

[Centri3]

Seems this only needs to be blessed, after that this is ready

[flip1995]

The failing test has a should not lint comment above it. And I have no idea how my changes could've changed the lint behavior here...

[bors]

☔ The latest upstream changes (presumably #11879) made this pull request unmergeable. Please resolve the merge conflicts.

[flip1995]

I've spent some time investigating this.

fn bar() {}  // or a `mod bar {}` or a `use` item
fn foo() {}

async fn _f(v: &mut Vec<()>) {
    let x = || v.pop();
    _ = || || x;
}

When removing anything from that reproducer, like the functions foo OR bar, the lint no longer triggers for _f. Also when changing the function body of _f, like removing the _ = || || x; makes the lint stop triggering. Moving one of the functions to after _f also makes the lint stop triggering.

So it seems like, in order to hit this, there must be at least 2 items before _f. Changing one of the functions to a module still triggers the lint. I have no idea how my changes in this PR have any influence on the behavior. I tried moving the check for exported(_api) to right before the span_lint_hir_and_then call, to rule out that my changes skip any side effects, but to no avail.

[GuillaumeGomez]

I completely forgot about it. ^^'

Putting it back to my to do list.

[xFrednet]

Sorry, I totally forgot about this PR, since it wasn't in my inbox anymore 🙈 I'll add it to my todo list. You'll get a review next week!

[xFrednet]

I totally missed this, since it wasn't in my inbox 🙈 I'll try to review it tomorrow or otherwise early next week.

Also ping @GuillaumeGomez, if you still want to help with the review

[xFrednet]

Sorry for the long review time, it wasn't in my inbox 🙈

Anyhow, one small nit, but the current version also looks good to me.

[xFrednet]

I think it would be cleaner to have this check in check_fn where the function is added to NeedlessPassByRefMut::fn_def_ids_to_maybe_unused_mut. (Or where it wouldn't be added if it's exported and the config is set) But this is a viable position as well.

[flip1995]

125c778

[xFrednet]

Could you also rebase the branch? :)

[flip1995]

Rebased and this weird bug: #11647 (comment) is also gone. Infinite monkey problem solving never disappoints!

[xFrednet]

LGTM, thank you for the quick update =^.^=

Now, let's give our favorite non money something to do.

---

Roses are red,
Bors is a bot,
Not a monkey,
Just automated testing slots

[bors]

📌 Commit 125c778 has been approved by xFrednet

It is now in the queue for this repository.

[bors]

⌛ Testing commit 125c778 with merge 51200cb...

[bors]

💔 Test failed - checks-action_test

[xFrednet]

Could you run cargo metadata-collection to update the documentation? Then you can r=me

[flip1995]

@bors r=xFrednet

Thanks for the review!

[bors]

📌 Commit ae47b97 has been approved by xFrednet

It is now in the queue for this repository.

[bors]

⌛ Testing commit ae47b97 with merge 918ae1b...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: xFrednet
Pushing 918ae1b to master...

[flip1995]

With this merged, I think we can move this lint out of nursery. Or are there any known issues left that we need to fix @GuillaumeGomez ?

[GuillaumeGomez]

None that I heard of at least.

[flip1995]

It triggers quite a bit on the 400 most popular crates. I still have to look into the source, whether any of those are FPs.

Going through the first 10 or so I found two issues: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=90b85826ab9d38fed7ff9657f7d24287

1. &mut (especially &mut self) is used sometimes to guarantee unique access. For example, when (mut) pointer arithmetic is involved. Removing the mut would introduce a bug
2. mocked/empty functions (for testing) also trigger the lint

clippy 0.1.81 (f7f0cd395c0 2024-07-02)

Reports

file	lint	message
target/lintcheck/sources/allocator-api2-0.2.18/src/stable/vec/into_iter.rs:83:83	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/allocator-api2-0.2.18/src/stable/vec/mod.rs:1216:1216	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/anyhow-1.0.86/src/ptr.rs:55:55	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/async-io-2.3.3/src/lib.rs:446:446	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/async-io-2.3.3/src/reactor.rs:439:439	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/backtrace-0.3.73/src/print.rs:63:63	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/backtrace-0.3.73/src/print.rs:85:85	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/bindgen-0.69.4/ir/analysis/derive.rs:416:416	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/bindgen-0.69.4/ir/item.rs:117:117	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/bindgen-0.69.4/time.rs:35:35	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/bit-vec-0.7.0/src/lib.rs:1756:1756	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/bitvec-1.0.1/src/boxed.rs:256:256	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/bitvec-1.0.1/src/domain.rs:827:827	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/bitvec-1.0.1/src/domain.rs:841:841	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/bitvec-1.0.1/src/domain.rs:852:852	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/bitvec-1.0.1/src/domain.rs:863:863	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/bitvec-1.0.1/src/vec.rs:336:336	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/bitvec-1.0.1/src/vec.rs:370:370	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/brotli-6.0.0/src/enc/block_splitter.rs:412:412	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/brotli-6.0.0/src/enc/brotli_bit_stream.rs:2116:2116	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/brotli-6.0.0/src/enc/context_map_entropy.rs:385:385	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/brotli-6.0.0/src/enc/context_map_entropy.rs:407:407	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/brotli-6.0.0/src/enc/encode.rs:1683:1683	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/brotli-6.0.0/src/enc/entropy_encode.rs:28:28	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/brotli-6.0.0/src/enc/find_stride.rs:886:886	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/brotli-6.0.0/src/enc/worker_pool.rs:164:164	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/brotli-6.0.0/src/enc/worker_pool.rs:179:179	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/brotli-decompressor-4.0.1/src/bit_reader/mod.rs:390:390	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/brotli-decompressor-4.0.1/src/decode.rs:604:604	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/clap_builder-4.5.8/src/builder/arg_group.rs:283:283	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/clap_builder-4.5.8/src/builder/styled_str.rs:76:76	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/clap_builder-4.5.8/src/parser/parser.rs:737:737	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/clap_builder-4.5.8/src/parser/validator.rs:27:27	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/clap_builder-4.5.8/src/parser/validator.rs:89:89	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/dashmap-6.0.1/src/lib.rs:891:891	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/encoding_rs-0.8.34/src/replacement.rs:37:37	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/encoding_rs-0.8.34/src/replacement.rs:56:56	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/encoding_rs-0.8.34/src/single_byte.rs:403:403	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/encoding_rs-0.8.34/src/utf_8.rs:845:845	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/encoding_rs-0.8.34/src/utf_8.rs:863:863	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/encoding_rs-0.8.34/src/x_user_defined.rs:75:75	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/env_logger-0.11.3/src/fmt/mod.rs:151:151	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/env_logger-0.11.3/src/fmt/writer/buffer.rs:127:127	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/event-listener-5.3.1/src/lib.rs:1170:1170	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/futures-channel-0.3.30/src/mpsc/mod.rs:805:805	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/futures-channel-0.3.30/src/oneshot.rs:154:154	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/futures-channel-0.3.30/src/oneshot.rs:256:256	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/futures-channel-0.3.30/src/oneshot.rs:357:357	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/futures-channel-0.3.30/src/oneshot.rs:438:438	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/futures-channel-0.3.30/src/oneshot.rs:450:450	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/futures-executor-0.3.30/src/local_pool.rs:295:295	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/futures-util-0.3.30/src/future/future/shared.rs:208:208	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/futures-util-0.3.30/src/stream/futures_unordered/mod.rs:248:248	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/futures-util-0.3.30/src/stream/select_all.rs:64:64	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/client.rs:1501:1501	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/hpack/encoder.rs:115:115	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/hpack/encoder.rs:157:157	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/recv.rs:1137:1137	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/recv.rs:130:130	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/recv.rs:784:784	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/recv.rs:822:822	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/recv.rs:836:836	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/send.rs:130:130	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/send.rs:321:321	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1058:1058	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1082:1082	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1102:1102	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1115:1115	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1139:1139	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1216:1216	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:121:121	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1238:1238	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1249:1249	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1293:1293	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1303:1303	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:130:130	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1330:1330	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1339:1339	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1366:1366	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1378:1378	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:157:157	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:1585:1585	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:169:169	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:178:178	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:190:190	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:211:211	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:219:219	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:334:334	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:340:340	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:345:345	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:352:352	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:357:357	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:366:366	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:371:371	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:376:376	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:381:381	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:386:386	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:947:947	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/proto/streams/streams.rs:989:989	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/share.rs:422:422	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/share.rs:556:556	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/h2-0.4.5/src/share.rs:569:569	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/hashbrown-0.14.5/src/raw/mod.rs:1487:1487	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/hashlink-0.9.1/src/linked_hash_map.rs:139:139	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/idna-1.0.2/src/deprecated.rs:109:109	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/idna-1.0.2/src/deprecated.rs:78:78	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/inout-0.2.0-pre.4/src/inout.rs:16:16	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/inout-0.2.0-pre.4/src/inout_buf.rs:138:138	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/libz-sys-1.1.18/build.rs:218:218	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/linked-hash-map-0.5.6/src/lib.rs:143:143	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/linked-hash-map-0.5.6/src/lib.rs:402:402	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/lru-0.12.3/src/lib.rs:1243:1243	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/matchit-0.8.3/src/router.rs:86:86	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/memmap2-0.9.4/src/unix.rs:361:361	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/miniz_oxide-0.7.4/src/inflate/core.rs:980:980	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/mio-1.0.0/src/poll.rs:432:432	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/object-0.36.1/src/read/read_cache.rs:90:90	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/openssl-0.10.64/src/x509/extension.rs:502:502	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/openssl-0.10.64/src/x509/extension.rs:512:512	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/pest-2.7.11/src/pratt_parser.rs:378:378	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/petgraph-0.6.5/src/algo/feedback_arc_set.rs:361:361	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/petgraph-0.6.5/src/algo/isomorphism.rs:283:283	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/petgraph-0.6.5/src/algo/isomorphism.rs:464:464	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/petgraph-0.6.5/src/algo/isomorphism.rs:508:508	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/prettyplease-0.2.20/src/expr.rs:669:669	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/prettyplease-0.2.20/src/generics.rs:147:147	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/prettyplease-0.2.20/src/pat.rs:172:172	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/prettyplease-0.2.20/src/ty.rs:166:166	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/prost-build-0.12.6/src/config.rs:1067:1067	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/quick-xml-0.35.0/src/reader/ns_reader.rs:188:188	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/quick-xml-0.35.0/src/reader/state.rs:60:60	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/regex-automata-0.4.7/src/dfa/minimize.rs:350:350	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/regex-automata-0.4.7/src/dfa/minimize.rs:358:358	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/regex-automata-0.4.7/src/dfa/minimize.rs:363:363	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/regex-automata-0.4.7/src/hybrid/regex.rs:665:665	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/regex-automata-0.4.7/src/hybrid/regex.rs:670:670	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/regex-automata-0.4.7/src/nfa/thompson/map.rs:158:158	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/regex-automata-0.4.7/src/nfa/thompson/map.rs:272:272	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/regex-syntax-0.8.4/src/ast/print.rs:62:62	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/regex-syntax-0.8.4/src/hir/print.rs:72:72	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/regex-syntax-0.8.4/src/hir/translate.rs:173:173	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/regex-syntax-0.8.4/src/hir/visitor.rs:161:161	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/rustix-0.38.34/src/backend/linux_raw/io/syscalls.rs:115:115	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/rustix-0.38.34/src/backend/linux_raw/io/syscalls.rs:84:84	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/rustix-0.38.34/src/backend/linux_raw/io/syscalls.rs:93:93	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/rustls-0.23.10/src/client/tls13.rs:1438:1438	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/rustls-0.23.10/src/common_state.rs:532:532	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/rustls-0.23.10/src/msgs/deframer.rs:346:346	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/rustls-0.23.10/src/server/tls13.rs:113:113	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/rustls-0.23.10/src/tls13/key_schedule.rs:217:217	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/serde_derive-1.0.203/src/bound.rs:241:241	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/serde_derive-1.0.203/src/internals/receiver.rs:291:291	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/serde_json-1.0.120/src/de.rs:634:634	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/socket2-0.5.7/src/lib.rs:695:695	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/tokio-1.38.0/src/runtime/park.rs:253:253	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/tokio-1.38.0/src/runtime/park.rs:258:258	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/tokio-1.38.0/src/runtime/park.rs:59:59	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/tokio-1.38.0/src/runtime/park.rs:65:65	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/tokio-1.38.0/src/runtime/park.rs:76:76	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/toml_edit-0.22.14/src/parser/mod.rs:116:116	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/tonic-0.11.0/src/codec/compression.rs:34:34	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/tonic-0.11.0/src/transport/server/mod.rs:360:360	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/tonic-0.11.0/src/transport/server/mod.rs:381:381	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/tonic-0.11.0/src/transport/server/mod.rs:399:399	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/vcpkg-0.2.15/src/lib.rs:1173:1173	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/vcpkg-0.2.15/src/lib.rs:1214:1214	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/walkdir-2.5.0/src/lib.rs:991:991	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/want-0.3.1/src/lib.rs:192:192	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/want-0.3.1/src/lib.rs:192:192	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"
target/lintcheck/sources/want-0.3.1/src/lib.rs:341:341	clippy::needless_pass_by_ref_mut	"this argument is a mutable reference, but not used mutably"

Stats:

lint	count
clippy::needless_pass_by_ref_mut	170