93 lines
2.4 KiB
Rust
93 lines
2.4 KiB
Rust
// Copyright 2013 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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// Exercise the unused_mut attribute in some positive and negative cases
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#![allow(unused_assignments)]
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#![allow(unused_variables)]
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#![allow(dead_code)]
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#![deny(unused_mut)]
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fn main() {
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// negative cases
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let mut a = 3; //~ ERROR: variable does not need to be mutable
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let mut a = 2; //~ ERROR: variable does not need to be mutable
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let mut b = 3; //~ ERROR: variable does not need to be mutable
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let mut a = vec!(3); //~ ERROR: variable does not need to be mutable
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let (mut a, b) = (1, 2); //~ ERROR: variable does not need to be mutable
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let mut a; //~ ERROR: variable does not need to be mutable
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a = 3;
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let mut b; //~ ERROR: variable does not need to be mutable
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if true {
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b = 3;
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} else {
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b = 4;
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}
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match 30 {
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mut x => {} //~ ERROR: variable does not need to be mutable
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}
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match (30, 2) {
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(mut x, 1) | //~ ERROR: variable does not need to be mutable
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(mut x, 2) |
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(mut x, 3) => {
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}
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_ => {}
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}
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let x = |mut y: isize| 10; //~ ERROR: variable does not need to be mutable
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fn what(mut foo: isize) {} //~ ERROR: variable does not need to be mutable
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// positive cases
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let mut a = 2;
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a = 3;
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let mut a = Vec::new();
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a.push(3);
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let mut a = Vec::new();
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callback(|| {
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a.push(3);
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});
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let (mut a, b) = (1, 2);
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a = 34;
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match 30 {
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mut x => {
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x = 21;
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}
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}
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match (30, 2) {
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(mut x, 1) |
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(mut x, 2) |
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(mut x, 3) => {
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x = 21
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}
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_ => {}
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}
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let x = |mut y: isize| y = 32;
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fn nothing(mut foo: isize) { foo = 37; }
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// leading underscore should avoid the warning, just like the
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// unused variable lint.
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let mut _allowed = 1;
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}
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fn callback<F>(f: F) where F: FnOnce() {}
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// make sure the lint attribute can be turned off
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#[allow(unused_mut)]
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fn foo(mut a: isize) {
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let mut a = 3;
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let mut b = vec!(2);
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}
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