rust/src/test/compile-fail/borrowck-partial-reinit-2.rs
Kevin Butler 32d0dbd49a librustc: Forbid partial reinitialization of uninitialized structures or
enumerations that implement the `Drop` trait.

This breaks code like:

    struct Struct {
        f: String,
        g: String,
    }

    impl Drop for Struct { ... }

    fn main() {
        let x = Struct { ... };
        drop(x);
        x.f = ...;
    }

Change this code to not create partially-initialized structures. For
example:

    struct Struct {
        f: String,
        g: String,
    }

    impl Drop for Struct { ... }

    fn main() {
        let x = Struct { ... };
        drop(x);
        x = Struct {
            f: ...,
            g: ...,
        }
    }

Closes #18571.

[breaking-change]

----

(Joint authorship by pcwalton and Ryman; thanks all!)
2015-02-12 13:55:08 +01:00

35 lines
912 B
Rust

// Copyright 2014-2015 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.
struct Test {
a: isize,
b: Option<Box<Test>>,
}
impl Drop for Test {
fn drop(&mut self) {
println!("Dropping {}", self.a);
}
}
fn stuff() {
let mut t = Test { a: 1, b: None};
let mut u = Test { a: 2, b: Some(Box::new(t))};
t.b = Some(Box::new(u));
//~^ ERROR partial reinitialization of uninitialized structure `t`
println!("done");
}
fn main() {
stuff();
println!("Hello, world!")
}