src/test/run-pass/type-ascription.rs

// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

#![allow(dead_code)]
#![allow(unused_variables)]
// Type ascription doesn't lead to unsoundness

#![feature(type_ascription)]

use std::mem;

const C1: u8 = 10: u8;
const C2: [u8; 1: usize] = [1];

struct S {
    a: u8
}

fn main() {
    assert_eq!(C1.into(): i32, 10);
    assert_eq!(C2[0], 1);

    let s = S { a: 10: u8 };
    let arr = &[1u8, 2, 3];

    let mut v = arr.iter().cloned().collect(): Vec<_>;
    v.push(4);
    assert_eq!(v, [1, 2, 3, 4]);

    let a = 1: u8;
    let b = a.into(): u16;
    assert_eq!(v[a.into(): usize], 2);
    assert_eq!(mem::size_of_val(&a), 1);
    assert_eq!(mem::size_of_val(&b), 2);
    assert_eq!(b, 1: u16);

    let mut v = Vec::new();
    v: Vec<u8> = vec![1, 2, 3]; // Place expression type ascription
    assert_eq!(v, [1u8, 2, 3]);
}