rust/tests/ui/liveness/liveness-unused.rs

142 lines
2.4 KiB
Rust

#![warn(unused)]
#![deny(unused_variables)]
#![deny(unused_assignments)]
#![allow(dead_code, non_camel_case_types, trivial_numeric_casts, drop_copy)]
use std::ops::AddAssign;
fn f1(x: isize) {
//~^ ERROR unused variable: `x`
}
fn f1b(x: &mut isize) {
//~^ ERROR unused variable: `x`
}
#[allow(unused_variables)]
fn f1c(x: isize) {}
fn f1d() {
let x: isize;
//~^ ERROR unused variable: `x`
}
fn f2() {
let x = 3;
//~^ ERROR unused variable: `x`
}
fn f3() {
let mut x = 3;
//~^ ERROR variable `x` is assigned to, but never used
x += 4;
//~^ ERROR value assigned to `x` is never read
}
fn f3b() {
let mut z = 3;
//~^ ERROR variable `z` is assigned to, but never used
loop {
z += 4;
}
}
#[allow(unused_variables)]
fn f3c() {
let mut z = 3;
loop { z += 4; }
}
#[allow(unused_variables)]
#[allow(unused_assignments)]
fn f3d() {
let mut x = 3;
x += 4;
}
fn f4() {
match Some(3) {
Some(i) => {
//~^ ERROR unused variable: `i`
}
None => {}
}
}
enum tri {
a(isize), b(isize), c(isize)
}
fn f4b() -> isize {
match tri::a(3) {
tri::a(i) | tri::b(i) | tri::c(i) => {
i
}
}
}
fn f5a() {
for x in 1..10 { }
//~^ ERROR unused variable: `x`
}
fn f5b() {
for (x, _) in [1, 2, 3].iter().enumerate() { }
//~^ ERROR unused variable: `x`
}
fn f5c() {
for (_, x) in [1, 2, 3].iter().enumerate() {
//~^ ERROR unused variable: `x`
continue;
drop(*x as i32); //~ WARNING unreachable statement
}
}
struct View<'a>(&'a mut [i32]);
impl<'a> AddAssign<i32> for View<'a> {
fn add_assign(&mut self, rhs: i32) {
for lhs in self.0.iter_mut() {
*lhs += rhs;
}
}
}
fn f6() {
let mut array = [1, 2, 3];
let mut v = View(&mut array);
// ensure an error shows up for x even if lhs of an overloaded add assign
let x;
//~^ ERROR variable `x` is assigned to, but never used
*({
x = 0; //~ ERROR value assigned to `x` is never read
&mut v
}) += 1;
}
struct MutRef<'a>(&'a mut i32);
impl<'a> AddAssign<i32> for MutRef<'a> {
fn add_assign(&mut self, rhs: i32) {
*self.0 += rhs;
}
}
fn f7() {
let mut a = 1;
{
// `b` does not trigger unused_variables
let mut b = MutRef(&mut a);
b += 1;
}
drop(a);
}
fn main() {
}