`cmp_null` autofix generates incorrect code

[yuvald-sweet-security]

Summary

the cmp_null autofix doesn't take into account the type of comparison, and instead always replaces the statement with a positive comparison on is_null().

Reproducer

I tried this code:

fn f(x: *mut i32) {
    if x != std::ptr::null_mut() {
        unsafe {
            *x += 1;
        }
    }
}

I expected to see this happen:

fn f(x: *mut i32) {
    if !x.is_null() {
        unsafe {
            *x += 1;
        }
    }
}

Instead, this happened:

fn f(x: *mut i32) {
    if x.is_null() {
        unsafe {
            *x += 1;
        }
    }
}

Version

clippy 0.1.87 (17067e9ac6 2025-05-09)

Additional Labels

No response

[yuvald-sweet-security]

nevermind, I see this was already fixed in nightly