src/test/run-pass/coerce-expect-unsized.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 // pretty-expanded FIXME #23616
  12
  13 #![allow(unknown_features)]
  14 #![feature(box_syntax)]
  15
  16 use std::cell::RefCell;
  17 use std::fmt::Debug;
  18 use std::rc::Rc;
  19
  20 // Check that coercions apply at the pointer level and don't cause
  21 // rvalue expressions to be unsized. See #20169 for more information.
  22
  23 pub fn main() {
  24     // FIXME #22405: We cannot infer the type `Box<[isize; k]>` for
  25     // the r-value expression from the context `Box<[isize]>`, and
  26     // therefore the `box EXPR` desugaring breaks down.
  27     //
  28     // One could reasonably claim that the `box EXPR` desugaring is
  29     // effectively regressing half of Issue #20169. Hopefully we will
  30     // eventually fix that, at which point the `Box::new` calls below
  31     // should be replaced wth uses of `box`.
  32
  33     let _: Box<[isize]> = Box::new({ [1, 2, 3] });
  34     let _: Box<[isize]> = Box::new(if true { [1, 2, 3] } else { [1, 3, 4] });
  35     let _: Box<[isize]> = Box::new(match true { true => [1, 2, 3], false => [1, 3, 4] });
  36     let _: Box<Fn(isize) -> _> = Box::new({ |x| (x as u8) });
  37     let _: Box<Debug> = Box::new(if true { false } else { true });
  38     let _: Box<Debug> = Box::new(match true { true => 'a', false => 'b' });
  39
  40     let _: &[isize] = &{ [1, 2, 3] };
  41     let _: &[isize] = &if true { [1, 2, 3] } else { [1, 3, 4] };
  42     let _: &[isize] = &match true { true => [1, 2, 3], false => [1, 3, 4] };
  43     let _: &Fn(isize) -> _ = &{ |x| (x as u8) };
  44     let _: &Debug = &if true { false } else { true };
  45     let _: &Debug = &match true { true => 'a', false => 'b' };
  46
  47     let _: Box<[isize]> = Box::new([1, 2, 3]);
  48     let _: Box<Fn(isize) -> _> = Box::new(|x| (x as u8));
  49
  50     let _: Rc<RefCell<[isize]>> = Rc::new(RefCell::new([1, 2, 3]));
  51     let _: Rc<RefCell<FnMut(isize) -> _>> = Rc::new(RefCell::new(|x| (x as u8)));
  52
  53     let _: Vec<Box<Fn(isize) -> _>> = vec![
  54         Box::new(|x| (x as u8)),
  55         Box::new(|x| (x as i16 as u8)),
  56     ];
  57 }