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// Copyright 2013 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.
// Exercise the unused_mut attribute in some positive and negative cases
#![allow(unused_assignments)]
#![allow(unused_variables)]
#![allow(dead_code)]
#![deny(unused_mut)]
fn main() {
// negative cases
let mut a = 3; //~ ERROR: variable does not need to be mutable
let mut a = 2; //~ ERROR: variable does not need to be mutable
let mut b = 3; //~ ERROR: variable does not need to be mutable
let mut a = vec!(3); //~ ERROR: variable does not need to be mutable
let (mut a, b) = (1, 2); //~ ERROR: variable does not need to be mutable
match 30 {
mut x => {} //~ ERROR: variable does not need to be mutable
}
match (30, 2) {
(mut x, 1) | //~ ERROR: variable does not need to be mutable
(mut x, 2) |
(mut x, 3) => {
}
_ => {}
}
let x = |mut y: isize| 10; //~ ERROR: variable does not need to be mutable
fn what(mut foo: isize) {} //~ ERROR: variable does not need to be mutable
// positive cases
let mut a = 2;
a = 3;
let mut a = Vec::new();
a.push(3);
let mut a = Vec::new();
callback(|| {
a.push(3);
});
let (mut a, b) = (1, 2);
a = 34;
match 30 {
mut x => {
x = 21;
}
}
match (30, 2) {
(mut x, 1) |
(mut x, 2) |
(mut x, 3) => {
x = 21
}
_ => {}
}
let x = |mut y: isize| y = 32;
fn nothing(mut foo: isize) { foo = 37; }
// leading underscore should avoid the warning, just like the
// unused variable lint.
let mut _allowed = 1;
}
fn callback<F>(f: F) where F: FnOnce() {}
// make sure the lint attribute can be turned off
#[allow(unused_mut)]
fn foo(mut a: isize) {
let mut a = 3;
let mut b = vec!(2);
}
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