`manual_filter` suggests replacing and_then requiring mutable access with filter

[programmerlexi]

Summary

Clippy suggest changing an Option::and_then usage with required mutable access into a Option::filter, when the manual_filter lint is active.

Reproducer

I have the following in my code:

Uart16550Tty::new_port(0x3f8, Config::DEFAULT)
    .ok()
    .and_then(|mut uart| {
        if uart.inner_mut().check_present() && uart.inner_mut().check_connected().is_ok() {
           Some(uart)
        } else {
            None
        }
    })

clippy suggest i replace the it with

Uart16550Tty::new_port(0x3f8, Config::DEFAULT)
    .ok()
    .filter(|mut uart| uart.inner_mut().check_present() && uart.inner_mut().check_connected().is_ok())

which is quite obviously incorrect and doesn't compile.

Version

rustc 1.100.0-nightly (feaadeeac 2026-09-19)
binary: rustc
commit-hash: feaadeeaca7db0594da854e7c8c07495341c7439
commit-date: 2026-09-19
host: x86_64-unknown-linux-gnu
release: 1.100.0-nightly
LLVM version: 23.1.1

Additional Labels

@rustbot label +I-suggestion-causes-error

[bhirahatees-periyasamy]

I was able to reproduce this. manual_filter fires on the and_then closure, but the suggested filter(|mut uart| ...) fails with E0596 because Option::filter passes &T to the predicate, so methods requiring &mut self cannot be called on it.

I'd like to work on this. @rustbot claim