clippy::ptr_eq: use `std::ptr::eq` when comparing raw pointers

What you see

warning: use `std::ptr::eq` when comparing raw pointers
 --> main.rs:6:9
  |
6 | assert!(a as *const _ as usize == b as *const _ as usize);
  |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::ptr::eq(a, b)`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#ptr_eq
  = note: `#[warn(clippy::ptr_eq)]` on by default

Real output of Clippy 0.1.99 (Rust 1.99) on the example below. Names and line numbers in yours will differ.

Does it matter?

ptr::eq can be used to compare &T references (which coerce to *const T implicitly) by their address rather than comparing the values they point to.

Code that works but is not idiomatic Rust. Warns by default.

How to fix it

Clippy can fix this one for you: run cargo clippy --fix (add --allow-dirty if you have uncommitted changes). Review the diff before you commit.

Flagged

let a = &[1, 2, 3];
let b = &[1, 2, 3];

assert!(a as *const _ as usize == b as *const _ as usize);

Write this instead

let a = &[1, 2, 3];
let b = &[1, 2, 3];

assert!(std::ptr::eq(a, b));

Turn it off, or on

Allow it where it does not fit your code, as narrowly as you can:

#[allow(clippy::ptr_eq)]
fn my_function() { /* ... */ }

[lints.clippy]
ptr_eq = "allow"

cargo clippy -- -A clippy::ptr-eq

The [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.