src/test/run-pass/mir_fat_ptr.rs

   1 // Copyright 2015 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 ordinary fat pointer operations work.
  12
  13 #![feature(rustc_attrs)]
  14
  15 struct Wrapper<T: ?Sized>(u32, T);
  16
  17 struct FatPtrContainer<'a> {
  18     ptr: &'a [u8]
  19 }
  20
  21 #[rustc_mir]
  22 fn fat_ptr_project(a: &Wrapper<[u8]>) -> &[u8] {
  23     &a.1
  24 }
  25
  26 #[rustc_mir]
  27 fn fat_ptr_simple(a: &[u8]) -> &[u8] {
  28     a
  29 }
  30
  31 #[rustc_mir]
  32 fn fat_ptr_via_local(a: &[u8]) -> &[u8] {
  33     let x = a;
  34     x
  35 }
  36
  37 #[rustc_mir]
  38 fn fat_ptr_from_struct(s: FatPtrContainer) -> &[u8] {
  39     s.ptr
  40 }
  41
  42 #[rustc_mir]
  43 fn fat_ptr_to_struct(a: &[u8]) -> FatPtrContainer {
  44     FatPtrContainer { ptr: a }
  45 }
  46
  47 #[rustc_mir]
  48 fn fat_ptr_store_to<'a>(a: &'a [u8], b: &mut &'a [u8]) {
  49     *b = a;
  50 }
  51
  52 fn main() {
  53     let a = Wrapper(4, [7,6,5]);
  54
  55     let p = fat_ptr_project(&a);
  56     let p = fat_ptr_simple(p);
  57     let p = fat_ptr_via_local(p);
  58     let p = fat_ptr_from_struct(fat_ptr_to_struct(p));
  59
  60     let mut target : &[u8] = &[42];
  61     fat_ptr_store_to(p, &mut target);
  62     assert_eq!(target, &a.1);
  63 }