pub static DEREF_NULLPTR: &LintExpand description
The deref_nullptr lint detects when a null pointer is dereferenced,
which causes undefined behavior.
§Example
use std::ptr;
unsafe {
    let x = &*ptr::null::<i32>();
    let x = ptr::addr_of!(*ptr::null::<i32>());
    let x = *(0 as *const i32);
}{{produces}}
§Explanation
Dereferencing a null pointer causes undefined behavior if it is accessed (loaded from or stored to).