rust/src/test/compile-fail/borrowck-assign-to-subfield.rs

43 lines
1.1 KiB
Rust

// Copyright 2012 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.
fn main() {
struct A {
a: int,
w: B,
x: @B,
y: @const B,
z: @mut B
}
struct B {
a: int
}
let mut p = A {
a: 1,
w: B {a: 1},
x: @B {a: 1},
y: @const B {a: 1},
z: @mut B {a: 1}
};
// even though `x` is not declared as a mutable field,
// `p` as a whole is mutable, so it can be modified.
p.a = 2;
// this is true for an interior field too
p.w.a = 2;
// in these cases we pass through a box, so the mut
// of the box is dominant
p.x.a = 2; //~ ERROR assigning to immutable field
p.y.a = 2; //~ ERROR assigning to const field
p.z.a = 2;
}