rust/src/test/compile-fail/borrowck-loan-blocks-mut-uniq.rs

fn borrow(v: &int, f: fn(x: &int)) {
    f(v);
}

fn box_imm() {
    let mut v = ~3;
    do borrow(v) |w| { //~ NOTE loan of mutable local variable granted here
        v = ~4; //~ ERROR assigning to captured outer mutable variable in a stack closure prohibited due to outstanding loan
        assert *v == 3;
        assert *w == 4;
    }
}

fn main() {
}