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.
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.
11 #![feature(coerce_unsized, unsize)]
13 use std::ops::CoerceUnsized;
14 use std::marker::Unsize;
16 fn identity_coercion(x: &(Fn(u32)->u32 + Send)) -> &Fn(u32)->u32 {
19 fn fn_coercions(f: &fn(u32) -> u32) ->
20 (unsafe fn(u32) -> u32,
21 &(Fn(u32) -> u32+Send))
26 fn simple_array_coercion(x: &[u8; 3]) -> &[u8] { x }
28 fn square(a: u32) -> u32 { a * a }
30 #[derive(PartialEq,Eq)]
31 struct PtrWrapper<'a, T: 'a+?Sized>(u32, u32, (), &'a T);
32 impl<'a, T: ?Sized+Unsize<U>, U: ?Sized>
33 CoerceUnsized<PtrWrapper<'a, U>> for PtrWrapper<'a, T> {}
35 struct TrivPtrWrapper<'a, T: 'a+?Sized>(&'a T);
36 impl<'a, T: ?Sized+Unsize<U>, U: ?Sized>
37 CoerceUnsized<TrivPtrWrapper<'a, U>> for TrivPtrWrapper<'a, T> {}
39 fn coerce_ptr_wrapper(p: PtrWrapper<[u8; 3]>) -> PtrWrapper<[u8]> {
43 fn coerce_triv_ptr_wrapper(p: TrivPtrWrapper<[u8; 3]>) -> TrivPtrWrapper<[u8]> {
47 fn coerce_fat_ptr_wrapper(p: PtrWrapper<Fn(u32) -> u32+Send>)
48 -> PtrWrapper<Fn(u32) -> u32> {
52 fn coerce_ptr_wrapper_poly<'a, T, Trait: ?Sized>(p: PtrWrapper<'a, T>)
53 -> PtrWrapper<'a, Trait>
54 where PtrWrapper<'a, T>: CoerceUnsized<PtrWrapper<'a, Trait>>
61 let square_local : fn(u32) -> u32 = square;
62 let (f,g) = fn_coercions(&square_local);
63 assert_eq!(f as usize, square as usize);
65 assert_eq!(identity_coercion(g)(5), 25);
67 assert_eq!(simple_array_coercion(&a), &a);
68 let w = coerce_ptr_wrapper(PtrWrapper(2,3,(),&a));
69 assert!(w == PtrWrapper(2,3,(),&a) as PtrWrapper<[u8]>);
71 let w = coerce_triv_ptr_wrapper(TrivPtrWrapper(&a));
74 let z = coerce_fat_ptr_wrapper(PtrWrapper(2,3,(),&square_local));
75 assert_eq!((z.3)(6), 36);
77 let z: PtrWrapper<Fn(u32) -> u32> =
78 coerce_ptr_wrapper_poly(PtrWrapper(2,3,(),&square_local));
79 assert_eq!((z.3)(6), 36);