message: Add intptrcast test for explicit casts
diff: // compile-flags: -Zmiri-seed=0000000000000000
  +fn transmute_ptr_to_int<T>(x: *const T) -> usize {
  + unsafe { std::mem::transmute::<*const T, usize>(x) * 1 }
  +}
  fn main() {
  // Some casting-to-int with arithmetic.
  @@ -11,4 +14,11 @@ fn main() {
  // Pointer string formatting! We can't check the output as it changes when libstd changes,
  // but we can make sure Miri does not error.
  format!("{:?}", &mut 13 as *mut _);
  +
  + // Check that intptrcast is triggered for explicit casts and that it is consistent with
  + // transmuting.
  + let a: *const i32 = &42;
  + let b = transmute_ptr_to_int(a) as u8;
  + let c = a as usize as u8;
  + assert_eq!(b, c);
  }
  