Attempted to cast to/from a pointer with an unknown kind.
Erroneous code examples:
let b = 0 as *const _; // error
Must give information for type of pointer that is being cast from/to if the type cannot be inferred.
// 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