src/test/compile-fail/vector-cast-weirdness.rs

   1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // Issue #14893. Tests that casts from vectors don't behave strangely in the
  12 // presence of the `_` type shorthand notation.
  13 // Update: after a change to the way casts are done, we have more type information
  14 // around and so the errors here are no longer exactly the same.
  15
  16 struct X {
  17     y: [u8; 2],
  18 }
  19
  20 fn main() {
  21     let x1 = X { y: [0, 0] };
  22
  23     // No longer a type mismatch - the `_` can be fully resolved by type inference.
  24     let p1: *const u8 = &x1.y as *const _;
  25     let t1: *const [u8; 2] = &x1.y as *const _;
  26     let h1: *const [u8; 2] = &x1.y as *const [u8; 2];
  27
  28     let mut x1 = X { y: [0, 0] };
  29
  30     // This is still an error since we don't allow casts from &mut [T; n] to *mut T.
  31     let p1: *mut u8 = &mut x1.y as *mut _;  //~ ERROR casting
  32     let t1: *mut [u8; 2] = &mut x1.y as *mut _;
  33     let h1: *mut [u8; 2] = &mut x1.y as *mut [u8; 2];
  34 }