src/test/run-pass/dst-deref.rs

   1 // Copyright 2014 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 // Test that a custom deref with a fat pointer return type does not ICE
  12
  13
  14 use std::ops::Deref;
  15
  16 pub struct Arr {
  17     ptr: Box<[usize]>
  18 }
  19
  20 impl Deref for Arr {
  21     type Target = [usize];
  22
  23     fn deref(&self) -> &[usize] {
  24         &*self.ptr
  25     }
  26 }
  27
  28 pub fn foo(arr: &Arr) {
  29     assert_eq!(arr.len(), 3);
  30     let x: &[usize] = &**arr;
  31     assert_eq!(x[0], 1);
  32     assert_eq!(x[1], 2);
  33     assert_eq!(x[2], 3);
  34 }
  35
  36 fn main() {
  37     // FIXME (#22405): Replace `Box::new` with `box` here when/if possible.
  38     let a = Arr { ptr: Box::new([1, 2, 3]) };
  39     foo(&a);
  40 }