trying, so far unsuccessfully, to exploit the lack of a value restriction on lifetime-polymorphic closures

gistfile1.rs

fn expect_static(z: &'static int) {
}

fn foo<'f>(x: @mut Option<&'f fn(&'static int)>, y: &'f fn(&'static int)) {
    *x = Some(y);
}

fn bar<'b>(x: @mut Option<&fn(&'b int)>) {
    let z = 5;
    match *x {
        Some(f) => f(&z),
        None => fail!("oops"),
    }   
}

fn main() {
    let a: @mut Option<&fn<'a>(&'a int)> = @mut None;
    foo(a, expect_static);
    bar(a);
}