Why is this an issue?

Using 0 as *const T or 0 as *mut T to represent a null pointer is error-prone and less readable. It can lead to confusion and potential bugs, as it is not immediately clear that 0 is intended to represent a null pointer. Additionally, using 0 for null pointers is not idiomatic Rust, and it can make the code harder to understand and maintain.

How to fix it

Use std::ptr::null or std::ptr::null_mut to represent null pointers. These functions are explicitly designed for this purpose and make the intent of the code clear.

Code examples

Noncompliant code example

let ptr = 0 as *const i32;
let mut_ptr = 0 as *mut i32;

Compliant solution

let ptr = std::ptr::null::<i32>();
let mut_ptr = std::ptr::null_mut::<i32>();

Resources

Documentation

• Clippy Lints - https://rust-lang.github.io/rust-clippy/master/index.html#zero_ptr