103 lines
2.7 KiB
Rust
103 lines
2.7 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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// Test that we choose Deref or DerefMut appropriately based on mutability of ref bindings (#15609).
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use std::ops::{Deref, DerefMut};
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struct DerefOk<T>(T);
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struct DerefMutOk<T>(T);
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impl<T> Deref for DerefOk<T> {
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type Target = T;
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fn deref(&self) -> &Self::Target {
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&self.0
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}
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}
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impl<T> DerefMut for DerefOk<T> {
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fn deref_mut(&mut self) -> &mut Self::Target {
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panic!()
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}
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}
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impl<T> Deref for DerefMutOk<T> {
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type Target = T;
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fn deref(&self) -> &Self::Target {
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panic!()
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}
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}
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impl<T> DerefMut for DerefMutOk<T> {
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fn deref_mut(&mut self) -> &mut Self::Target {
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&mut self.0
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}
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}
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fn main() {
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// Check that mutable ref binding in match picks DerefMut
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let mut b = DerefMutOk(0);
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match *b {
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ref mut n => n,
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};
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// Check that mutable ref binding in let picks DerefMut
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let mut y = DerefMutOk(1);
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let ref mut z = *y;
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// Check that immutable ref binding in match picks Deref
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let mut b = DerefOk(2);
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match *b {
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ref n => n,
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};
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// Check that immutable ref binding in let picks Deref
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let mut y = DerefOk(3);
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let ref z = *y;
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// Check that mixed mutable/immutable ref binding in match picks DerefMut
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let mut b = DerefMutOk((0, 9));
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match *b {
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(ref mut n, ref m) => (n, m),
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};
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let mut b = DerefMutOk((0, 9));
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match *b {
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(ref n, ref mut m) => (n, m),
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};
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// Check that mixed mutable/immutable ref binding in let picks DerefMut
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let mut y = DerefMutOk((1, 8));
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let (ref mut z, ref a) = *y;
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let mut y = DerefMutOk((1, 8));
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let (ref z, ref mut a) = *y;
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// Check that multiple immutable ref bindings in match picks Deref
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let mut b = DerefOk((2, 7));
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match *b {
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(ref n, ref m) => (n, m),
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};
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// Check that multiple immutable ref bindings in let picks Deref
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let mut y = DerefOk((3, 6));
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let (ref z, ref a) = *y;
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// Check that multiple mutable ref bindings in match picks DerefMut
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let mut b = DerefMutOk((4, 5));
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match *b {
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(ref mut n, ref mut m) => (n, m),
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};
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// Check that multiple mutable ref bindings in let picks DerefMut
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let mut y = DerefMutOk((5, 4));
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let (ref mut z, ref mut a) = *y;
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}
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