incorrect/useless lint warning [warn(dropping_references)]

[cavemanloverboy]

when compiling something like

let x = [0; 64];
let _ = drop(&x);

I see

warning: calls to `std::mem::drop` with a reference instead of an owned value does nothing
 --> src/main.rs:3:9
  |
3 | let _ = drop(&x);
  |         ^^^^^--^
  |              |
  |              argument has type `&[i32; 64]`
  |
  = note: use `let _ = ...` to ignore the expression or result
  = note: `#[warn(dropping_references)]` on by default

warning: `playground` (bin "playground") generated 1 warning

which gives me the note: use let _ = ... to ignore the expression or result. (the reason for the let _ = ... in the first place is because i listened to the suggestion)

Meta

$ rustc --version
rustc 1.95.0 (59807616e 2026-04-14)

this also happens on nightly

$ cargo +nightly  --version
cargo 1.97.0-nightly (06ac0e7c0 2026-04-21)

[LFS6502]

Possibly related issue: #125972

[Urgau]

The suggestion is to do let _ = x or let _ = &x;, i.e. to remove the drop call.

[LFS6502]

The suggestion is to do let _ = x or let _ = &x;, i.e. to remove the drop call.

Yeah, but that's not immediately apparent, the suggestion could use an improvement imo.

[Urgau]

The note being a bit vague is on purpose, let _ = only hides the warning, not the issue.

Dropping a reference is pretty much always a red-hearing, like if someone does drop(&mutex) or more incidus drop(mutex_ref). In those cases doing let _ = is incorrect.