src/test/run-pass/dst-tuple-sole.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 // As dst-tuple.rs, but the unsized field is the only field in the tuple.
  12
  13
  14 #![feature(unsized_tuple_coercion)]
  15
  16 type Fat<T: ?Sized> = (T,);
  17
  18 // x is a fat pointer
  19 fn foo(x: &Fat<[isize]>) {
  20     let y = &x.0;
  21     assert_eq!(x.0.len(), 3);
  22     assert_eq!(y[0], 1);
  23     assert_eq!(x.0[1], 2);
  24 }
  25
  26 fn foo2<T:ToBar>(x: &Fat<[T]>) {
  27     let y = &x.0;
  28     let bar = Bar;
  29     assert_eq!(x.0.len(), 3);
  30     assert_eq!(y[0].to_bar(), bar);
  31     assert_eq!(x.0[1].to_bar(), bar);
  32 }
  33
  34 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
  35 struct Bar;
  36
  37 trait ToBar {
  38     fn to_bar(&self) -> Bar;
  39 }
  40
  41 impl ToBar for Bar {
  42     fn to_bar(&self) -> Bar {
  43         *self
  44     }
  45 }
  46
  47 pub fn main() {
  48     // With a vec of ints.
  49     let f1 = ([1, 2, 3],);
  50     foo(&f1);
  51     let f2 = &f1;
  52     foo(f2);
  53     let f3: &Fat<[isize]> = f2;
  54     foo(f3);
  55     let f4: &Fat<[isize]> = &f1;
  56     foo(f4);
  57     let f5: &Fat<[isize]> = &([1, 2, 3],);
  58     foo(f5);
  59
  60     // With a vec of Bars.
  61     let bar = Bar;
  62     let f1 = ([bar, bar, bar],);
  63     foo2(&f1);
  64     let f2 = &f1;
  65     foo2(f2);
  66     let f3: &Fat<[Bar]> = f2;
  67     foo2(f3);
  68     let f4: &Fat<[Bar]> = &f1;
  69     foo2(f4);
  70     let f5: &Fat<[Bar]> = &([bar, bar, bar],);
  71     foo2(f5);
  72
  73     // Assignment.
  74     let f5: &mut Fat<[isize]> = &mut ([1, 2, 3],);
  75     f5.0[1] = 34;
  76     assert_eq!(f5.0[0], 1);
  77     assert_eq!(f5.0[1], 34);
  78     assert_eq!(f5.0[2], 3);
  79
  80     // Zero size vec.
  81     let f5: &Fat<[isize]> = &([],);
  82     assert!(f5.0.is_empty());
  83     let f5: &Fat<[Bar]> = &([],);
  84     assert!(f5.0.is_empty());
  85 }