rust/tests/compile-fail/shadow.rs

#![feature(plugin)]
#![plugin(clippy)]

#![allow(unused_parens, unused_variables)]
#![deny(clippy, clippy_pedantic)]

fn id<T>(x: T) -> T { x }

fn first(x: (isize, isize)) -> isize { x.0 }

fn main() {
    let mut x = 1;
    let x = &mut x; //~ERROR `x` is shadowed by itself in `&mut x`
    let x = { x }; //~ERROR `x` is shadowed by itself in `{ x }`
    let x = (&*x); //~ERROR `x` is shadowed by itself in `(&*x)`
    let x = { *x + 1 }; //~ERROR `x` is shadowed by `{ *x + 1 }` which reuses
    let x = id(x); //~ERROR `x` is shadowed by `id(x)` which reuses
    let x = (1, x); //~ERROR `x` is shadowed by `(1, x)` which reuses
    let x = first(x); //~ERROR `x` is shadowed by `first(x)` which reuses
    let y = 1;
    let x = y; //~ERROR `x` is shadowed by `y`

    let o = Some(1_u8);

    if let Some(p) = o { assert_eq!(1, p); }
    match o {
        Some(p) => p, // no error, because the p above is in its own scope
        None => 0,
    };

    match (x, o) {
        (1, Some(a)) | (a, Some(1)) => (), // no error though `a` appears twice
        _ => (),
    }
}