significant_drop_tightening suggests a change that makes no sense

Summary

The nursery significant_drop_tightening lint can end up suggesting placing a drop in a location that doesn't make sense.

Reproducer

Code:

use std::sync::Arc;

use parking_lot::{Condvar, Mutex};

struct Inner {
  error: Option<String>,
  eof: bool
}

struct Shared {
  inner: Mutex<Inner>,
  signal: Condvar
}

pub enum Outcome {
  HaveData(u64),
  Interrupted,
  Eof
}

pub fn foo(sh: &Arc<Shared>) -> Outcome {
  let mut rw = sh.inner.lock();
  loop {
    if rw.error.is_some() {
      break Outcome::Interrupted;
    } else if rw.eof {
      break Outcome::Eof;
    }
    sh.signal.wait(&mut rw);
  }
}

Cargo.toml contains:

[lints.clippy]
all = { level = "warn", priority = -1 }
cargo = { level = "warn", priority = -1 }
nursery = { level = "warn", priority = -1 }
pedantic = { level = "warn", priority = -1 }

cargo_common_metadata = "allow"

Current output:

Running cargo +beta clippy, includes:

 2  warning: temporary with significant `Drop` can be early dropped
   --> src/main.rs:22:11
    |
 21 |   pub fn foo(sh: &Arc<Shared>) -> Outcome {
    |  _________________________________________-
 22 | |   let mut rw = sh.inner.lock();
    | |           ^^
 23 | |   loop {
 24 | |     if rw.error.is_some() {
 ...  |
 31 | | }
    | |_- temporary `rw` is currently being dropped at the end of its contained scope
    |
    = note: this might lead to unnecessary resource contention
    = help: for further information visit https://rust-lang.github.io/rust-clippy/beta/index.html#significant_drop_tightening
    = note: `-W clippy::significant-drop-tightening` implied by `-W clippy::nursery`
    = help: to override `-W clippy::nursery` add `#[allow(clippy::significant_drop_tightening)]`
 help: drop the temporary after the end of its last usage
    |
 25 ~       break Outcome::Interrupted;
 26 +       drop(rw);

Desired output:
Probably a good idea to suggest placing the drop above the break?

Version

rustc 1.97.0-beta.4 (36645eb0d 2026-06-12)
binary: rustc
commit-hash: 36645eb0d0f62571c8ecc7d1c7446c5da758972f
commit-date: 2026-06-12
host: x86_64-apple-darwin
release: 1.97.0-beta.4
LLVM version: 22.1.6

Additional Labels

No response

Start with the significant_drop_tightening lint entry point and reproduce the warning using the Rust code and Cargo lints shown in the issue. Inspect how the suggested drop location is selected around the break expression. Done means the diagnostic no longer suggests an invalid location and instead points to a sensible placement, with the reproducer covered by a regression test.