Static DANGEROUS_IMPLICIT_AUTOREFS

pub static DANGEROUS_IMPLICIT_AUTOREFS: &Lint

The dangerous_implicit_autorefs lint checks for implicitly taken references to dereferences of raw pointers.

Example

unsafe fn fun(ptr: *mut [u8]) -> *mut [u8] {
    unsafe { &raw mut (*ptr)[..16] }
    //                      ^^^^^^ this calls `IndexMut::index_mut(&mut ..., ..16)`,
    //                             implicitly creating a reference
}

{{produces}}

Explanation

When working with raw pointers it’s usually undesirable to create references, since they inflict additional safety requirements. Unfortunately, it’s possible to take a reference to the dereference of a raw pointer implicitly, which inflicts the usual reference requirements.

If you are sure that you can soundly take a reference, then you can take it explicitly:

unsafe fn fun(ptr: *mut [u8]) -> *mut [u8] {
    unsafe { &raw mut (&mut *ptr)[..16] }
}

Otherwise try to find an alternative way to achive your goals using only raw pointers:

use std::ptr;

fn fun(ptr: *mut [u8]) -> *mut [u8] {
    ptr::slice_from_raw_parts_mut(ptr.cast(), 16)
}