unnecessary_unwrap emitted for chained expression

[asomers]

Summary

The unneccessary_unwrap lint should not be triggered when the preceding is_err(), is_ok(), or is_some() call is in a combined expression, at least not if the code is at Rust edition 2021 or older.

Lint Name

unnecessary_unwrap

Reproducer

I tried this code:

        if res.is_err() && !std::thread::panicking() {
            panic!("Failed to remove flock: {}", res.unwrap_err());
        }

I saw this happen:

error: called `unwrap_err` on `res` after checking its variant with `is_err`
    --> src/fcntl.rs:1045:50
     |
1044 |         if res.is_err() && !std::thread::panicking() {
     |            ------------ the check is happening here
1045 |             panic!("Failed to remove flock: {}", res.unwrap_err());
     |                                                  ^^^^^^^^^^^^^^^^
     |
     = help: try using `if let` or `match`
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
     = note: `-D clippy::unnecessary-unwrap` implied by `-D warnings`
     = help: to override `-D warnings` add `#[allow(clippy::unnecessary_unwrap)]`

I expected to see this happen:
No warning should be emitted. Because if I follow Clippy's advice and replace the is_err() call with if let, then the compile fails with this error:

error: let chains are only allowed in Rust 2024 or later
    --> src/fcntl.rs:1044:12
     |
1044 |         if let Err(e) = res && !std::thread::panicking() {
     |            ^^^^^^^^^^^^^^^^

Version

rustc 1.92.0-nightly (9f32ccf35 2025-09-21)
binary: rustc
commit-hash: 9f32ccf35fb877270bc44a86a126440f04d676d0
commit-date: 2025-09-21
host: x86_64-unknown-freebsd
release: 1.92.0-nightly
LLVM version: 21.1.1

Additional Labels

@rustbot label +I-suggestion-causes-error

[samueltardieu]

Note that the suggestion reads "try using if let or match", you could have used match here. But indeed, Clippy should not suggest if let when this is not applicable.

@rustbot claim