RS.CLIPPY.PTR_OFFSET_WITH_CAST

Unneeded pointer offset cast

This checker is a Clippy lint created by The Rust Project Contributors. The documentation shown here is a copy of the original documentation for: ptr_offset_with_cast. Copyright ©2025 The Rust Team. All rights reserved.

What it does

Checks for usage of the offset pointer method with a usize casted to an isize.

Why is this bad?

If we're always increasing the pointer address, we can avoid the numeric cast by using the add method instead.

Example

let vec = vec![b\'a\', b\'b\', b\'c\'];
let ptr = vec.as_ptr();
let offset = 1_usize;

unsafe {
    ptr.offset(offset as isize);
}

Could be written:

let vec = vec![b\'a\', b\'b\', b\'c\'];
let ptr = vec.as_ptr();
let offset = 1_usize;

unsafe {
    ptr.add(offset);
}