152 lines
3.2 KiB
Rust
152 lines
3.2 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Test how overloaded deref interacts with borrows when DerefMut
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// is implemented.
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use std::ops::{Deref, DerefMut};
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struct Own<T> {
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value: *mut T
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}
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impl<T> Deref<T> for Own<T> {
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fn deref<'a>(&'a self) -> &'a T {
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unsafe { &*self.value }
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}
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}
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impl<T> DerefMut<T> for Own<T> {
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fn deref_mut<'a>(&'a mut self) -> &'a mut T {
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unsafe { &mut *self.value }
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}
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}
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struct Point {
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x: int,
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y: int
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}
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impl Point {
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fn get(&self) -> (int, int) {
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(self.x, self.y)
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}
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fn set(&mut self, x: int, y: int) {
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self.x = x;
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self.y = y;
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}
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fn x_ref<'a>(&'a self) -> &'a int {
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&self.x
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}
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fn y_mut<'a>(&'a mut self) -> &'a mut int {
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&mut self.y
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}
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}
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fn deref_imm_field(x: Own<Point>) {
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let _i = &x.y;
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}
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fn deref_mut_field1(x: Own<Point>) {
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let _i = &mut x.y; //~ ERROR cannot borrow
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}
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fn deref_mut_field2(mut x: Own<Point>) {
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let _i = &mut x.y;
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}
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fn deref_extend_field<'a>(x: &'a Own<Point>) -> &'a int {
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&x.y
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}
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fn deref_extend_mut_field1<'a>(x: &'a Own<Point>) -> &'a mut int {
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&mut x.y //~ ERROR cannot borrow
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}
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fn deref_extend_mut_field2<'a>(x: &'a mut Own<Point>) -> &'a mut int {
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&mut x.y
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}
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fn deref_extend_mut_field3<'a>(x: &'a mut Own<Point>) {
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// Hmm, this is unfortunate, because with ~ it would work,
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// but it's presently the expected outcome. See `deref_extend_mut_field4`
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// for the workaround.
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let _x = &mut x.x;
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let _y = &mut x.y; //~ ERROR cannot borrow
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}
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fn deref_extend_mut_field4<'a>(x: &'a mut Own<Point>) {
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let p = &mut **x;
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let _x = &mut p.x;
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let _y = &mut p.y;
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}
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fn assign_field1<'a>(x: Own<Point>) {
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x.y = 3; //~ ERROR cannot borrow
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}
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fn assign_field2<'a>(x: &'a Own<Point>) {
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x.y = 3; //~ ERROR cannot assign
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}
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fn assign_field3<'a>(x: &'a mut Own<Point>) {
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x.y = 3;
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}
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fn assign_field4<'a>(x: &'a mut Own<Point>) {
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let _p: &mut Point = &mut **x;
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x.y = 3; //~ ERROR cannot borrow
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}
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// FIXME(eddyb) #12825 This shouldn't attempt to call deref_mut.
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/*
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fn deref_imm_method(x: Own<Point>) {
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let _i = x.get();
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}
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*/
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fn deref_mut_method1(x: Own<Point>) {
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x.set(0, 0); //~ ERROR cannot borrow
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}
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fn deref_mut_method2(mut x: Own<Point>) {
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x.set(0, 0);
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}
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fn deref_extend_method<'a>(x: &'a Own<Point>) -> &'a int {
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x.x_ref()
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}
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fn deref_extend_mut_method1<'a>(x: &'a Own<Point>) -> &'a mut int {
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x.y_mut() //~ ERROR cannot borrow
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}
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fn deref_extend_mut_method2<'a>(x: &'a mut Own<Point>) -> &'a mut int {
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x.y_mut()
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}
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fn assign_method1<'a>(x: Own<Point>) {
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*x.y_mut() = 3; //~ ERROR cannot borrow
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}
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fn assign_method2<'a>(x: &'a Own<Point>) {
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*x.y_mut() = 3; //~ ERROR cannot borrow
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}
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fn assign_method3<'a>(x: &'a mut Own<Point>) {
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*x.y_mut() = 3;
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}
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pub fn main() {}
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