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(rustc_attrs, coerce_unsized, unsize)]
13 use std::ops::CoerceUnsized;
14 use std::marker::Unsize;
17 fn identity_coercion(x: &(Fn(u32)->u32 + Send)) -> &Fn(u32)->u32 {
21 fn fn_coercions(f: &fn(u32) -> u32) ->
22 (unsafe fn(u32) -> u32,
23 &(Fn(u32) -> u32+Send))
29 fn simple_array_coercion(x: &[u8; 3]) -> &[u8] { x }
31 fn square(a: u32) -> u32 { a * a }
33 #[derive(PartialEq,Eq)]
34 struct PtrWrapper<'a, T: 'a+?Sized>(u32, u32, (), &'a T);
35 impl<'a, T: ?Sized+Unsize<U>, U: ?Sized>
36 CoerceUnsized<PtrWrapper<'a, U>> for PtrWrapper<'a, T> {}
38 struct TrivPtrWrapper<'a, T: 'a+?Sized>(&'a T);
39 impl<'a, T: ?Sized+Unsize<U>, U: ?Sized>
40 CoerceUnsized<TrivPtrWrapper<'a, U>> for TrivPtrWrapper<'a, T> {}
43 fn coerce_ptr_wrapper(p: PtrWrapper<[u8; 3]>) -> PtrWrapper<[u8]> {
48 fn coerce_triv_ptr_wrapper(p: TrivPtrWrapper<[u8; 3]>) -> TrivPtrWrapper<[u8]> {
53 fn coerce_fat_ptr_wrapper(p: PtrWrapper<Fn(u32) -> u32+Send>)
54 -> PtrWrapper<Fn(u32) -> u32> {
59 fn coerce_ptr_wrapper_poly<'a, T, Trait: ?Sized>(p: PtrWrapper<'a, T>)
60 -> PtrWrapper<'a, Trait>
61 where PtrWrapper<'a, T>: CoerceUnsized<PtrWrapper<'a, Trait>>
68 let square_local : fn(u32) -> u32 = square;
69 let (f,g) = fn_coercions(&square_local);
70 assert_eq!(f as usize, square as usize);
72 assert_eq!(identity_coercion(g)(5), 25);
74 assert_eq!(simple_array_coercion(&a), &a);
75 let w = coerce_ptr_wrapper(PtrWrapper(2,3,(),&a));
76 assert!(w == PtrWrapper(2,3,(),&a) as PtrWrapper<[u8]>);
78 let w = coerce_triv_ptr_wrapper(TrivPtrWrapper(&a));
81 let z = coerce_fat_ptr_wrapper(PtrWrapper(2,3,(),&square_local));
82 assert_eq!((z.3)(6), 36);
84 let z: PtrWrapper<Fn(u32) -> u32> =
85 coerce_ptr_wrapper_poly(PtrWrapper(2,3,(),&square_local));
86 assert_eq!((z.3)(6), 36);