compiler/rustc_error_codes/src/error_codes/E0641.md

   1 Attempted to cast to/from a pointer with an unknown kind.
   2
   3 Erroneous code example:
   4
   5 ```compile_fail,E0641
   6 let b = 0 as *const _; // error
   7 ```
   8
   9 Type information must be provided if a pointer type being cast from/into another
  10 type which cannot be inferred:
  11
  12 ```
  13 // Creating a pointer from reference: type can be inferred
  14 let a = &(String::from("Hello world!")) as *const _; // ok!
  15
  16 let b = 0 as *const i32; // ok!
  17
  18 let c: *const i32 = 0 as *const _; // ok!
  19 ```