rust/src/test/compile-fail/lint-unused-mut-variables.rs
2014-03-22 01:08:57 +11:00

69 lines
1.9 KiB
Rust

// 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(dead_assignment)];
#[allow(unused_variable)];
#[allow(dead_code)];
#[allow(deprecated_owned_vector)];
#[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
}
let x = |mut y: int| 10; //~ ERROR: variable does not need to be mutable
fn what(mut foo: int) {} //~ 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;
}
}
let x = |mut y: int| y = 32;
fn nothing(mut foo: int) { foo = 37; }
// leading underscore should avoid the warning, just like the
// unused variable lint.
let mut _allowed = 1;
}
fn callback(f: ||) {}
// make sure the lint attribute can be turned off
#[allow(unused_mut)]
fn foo(mut a: int) {
let mut a = 3;
let mut b = vec!(2);
}