rust/src/test/compile-fail/unsafe-mutable-alias.rs

// error-pattern:mutable alias to a variable that roots another alias

fn f(a: &{mutable x: int}, b: &mutable {mutable x: int}) -> int {
    b.x += 1; ret a.x + b.x;
}

fn main() { let i = {mutable x: 4}; log f(i, i); }