47 lines
1.2 KiB
Rust
47 lines
1.2 KiB
Rust
// Copyright 2015 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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// Check that we properly record borrows when we are doing an
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// overloaded, autoderef of a value obtained via an overloaded index
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// operator. The accounting of the all the implicit things going on
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// here is rather subtle. Issue #20232.
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use std::ops::{Deref, Index};
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struct MyVec<T> { x: T }
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impl<T> Index<usize> for MyVec<T> {
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type Output = T;
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fn index(&self, _: &usize) -> &T {
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&self.x
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}
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}
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struct MyPtr<T> { x: T }
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impl<T> Deref for MyPtr<T> {
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type Target = T;
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fn deref(&self) -> &T {
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&self.x
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}
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}
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struct Foo { f: usize }
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fn main() {
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let mut v = MyVec { x: MyPtr { x: Foo { f: 22 } } };
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let i = &v[0].f;
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v = MyVec { x: MyPtr { x: Foo { f: 23 } } };
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//~^ ERROR cannot assign to `v`
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read(*i);
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}
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fn read(_: usize) { }
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