Error code E0641
Attempted to cast to/from a pointer with an unknown kind.
Erroneous code example:
#![allow(unused)] fn main() { let b = 0 as *const _; // error }
Type information must be provided if a pointer type being cast from/into another type which cannot be inferred:
#![allow(unused)] fn main() { // Creating a pointer from reference: type can be inferred let a = &(String::from("Hello world!")) as *const _; // ok! let b = 0 as *const i32; // ok! let c: *const i32 = 0 as *const _; // ok! }