| // Copyright 2016 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. |
| |
| #![feature(untagged_unions)] |
| |
| union U1 { |
| a: u8 |
| } |
| |
| union U2 { |
| a: String |
| } |
| |
| union U3<T> { |
| a: T |
| } |
| |
| union U4<T: Copy> { |
| a: T |
| } |
| |
| fn generic_noncopy<T: Default>() { |
| let mut u3 = U3 { a: T::default() }; |
| u3.a = T::default(); //~ ERROR assignment to non-`Copy` union field is unsafe |
| } |
| |
| fn generic_copy<T: Copy + Default>() { |
| let mut u3 = U3 { a: T::default() }; |
| u3.a = T::default(); // OK |
| let mut u4 = U4 { a: T::default() }; |
| u4.a = T::default(); // OK |
| } |
| |
| fn main() { |
| let mut u1 = U1 { a: 10 }; // OK |
| let a = u1.a; //~ ERROR access to union field is unsafe |
| u1.a = 11; // OK |
| let U1 { a } = u1; //~ ERROR access to union field is unsafe |
| if let U1 { a: 12 } = u1 {} //~ ERROR access to union field is unsafe |
| // let U1 { .. } = u1; // OK |
| |
| let mut u2 = U2 { a: String::from("old") }; // OK |
| u2.a = String::from("new"); //~ ERROR assignment to non-`Copy` union field is unsafe |
| let mut u3 = U3 { a: 0 }; // OK |
| u3.a = 1; // OK |
| let mut u3 = U3 { a: String::from("old") }; // OK |
| u3.a = String::from("new"); //~ ERROR assignment to non-`Copy` union field is unsafe |
| } |