tuple_array_conversions triggers even when binding is used for more than tuple-array conversion

[mwkmwkmwk]

Summary

A lint about tuple-array conversions triggers when bindings created by tuple destructuring are used to create an array (or the other way around). However, the lint doesn't check whether this is the only use of such bindings, in which case using into() would harm readability by forcing changes to other binding uses.

Lint Name

tuple_array_conversions

Reproducer

I tried this code:

fn get_tuple() -> (i32, i32) {
    (1, 2)
}

fn iter_arrays() -> impl Iterator<Item = [i32; 2]> {
    [].into_iter()
}

fn do_something(_: i32) -> i32 {
    3
}

fn main() {
    let (a, b) = get_tuple();
    for x in [a, b] {
        println!("use both: {x}");
    }
    do_something(a);
    iter_arrays()
        .map(|[a, b]| (do_something(a), (a, b)))
        .for_each(drop);
}

I saw this happen:

$ cargo clippy
    Checking clt v0.1.0 (/home/mwk/clt)
warning: it looks like you're trying to convert a tuple to an array
  --> src/main.rs:15:14
   |
15 |     for x in [a, b] {
   |              ^^^^^^
   |
   = help: use `.into()` instead, or `<[T; N]>::from` if type annotations are needed
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#tuple_array_conversions
   = note: `#[warn(clippy::tuple_array_conversions)]` on by default

warning: it looks like you're trying to convert an array to a tuple
  --> src/main.rs:20:41
   |
20 |         .map(|[a, b]| (do_something(a), (a, b)))
   |                                         ^^^^^^
   |
   = help: use `.into()` instead, or `<(T0, T1, ..., Tn)>::from` if type annotations are needed
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#tuple_array_conversions

warning: `clt` (bin "clt") generated 2 warnings
    Finished dev [unoptimized + debuginfo] target(s) in 0.08s

I expected to see this happen:

(no warning)

Version

rustc 1.72.0-nightly (85bf07972 2023-07-06)
binary: rustc
commit-hash: 85bf07972a1041b9e25393b803d0e006bec3eaaf
commit-date: 2023-07-06
host: x86_64-unknown-linux-gnu
release: 1.72.0-nightly
LLVM version: 16.0.5

Additional Labels

No response

[TomFryersMidsummer]

This still seems to trigger in

rustc 1.74.0 (79e9716c9 2023-11-13)
binary: rustc
commit-hash: 79e9716c980570bfd1f666e3b16ac583f0168962
commit-date: 2023-11-13
host: x86_64-unknown-linux-gnu
release: 1.74.0
LLVM version: 17.0.4

and

rustc 1.76.0-nightly (1fdfe1234 2023-12-06)
binary: rustc
commit-hash: 1fdfe1234795a289af1088aefa92ef80191cb611
commit-date: 2023-12-06
host: x86_64-unknown-linux-gnu
release: 1.76.0-nightly
LLVM version: 17.0.5