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// Tests that a closure which requires mutable access to the referent
// of an `&mut` requires a "unique" borrow -- that is, the variable to
// be borrowed (here, `x`) will not be borrowed *mutably*, but
// may be *immutable*, but we cannot allow
// multiple borrows.
fn get(x: &isize) -> isize {
*x
}
fn set(x: &mut isize) -> isize {
*x
}
fn a(x: &mut isize) {
let c1 = || get(x);
let c2 = || get(x);
c1();
c2();
}
fn b(x: &mut isize) {
let c1 = || get(x);
let c2 = || set(x); //~ ERROR closure requires unique access to `x`
c1;
}
fn c(x: &mut isize) {
let c1 = || get(x);
let c2 = || { get(x); set(x); }; //~ ERROR closure requires unique access to `x`
c1;
}
fn d(x: &mut isize) {
let c1 = || set(x);
let c2 = || set(x); //~ ERROR two closures require unique access to `x` at the same time
c1;
}
fn e(x: &'static mut isize) {
let c1 = |y: &'static mut isize| x = y;
//~^ ERROR cannot assign to `x`, as it is not declared as mutable
c1;
}
fn f(x: &'static mut isize) {
let c1 = || x = panic!(); // OK assignment is unreachable.
c1;
}
fn main() {
}
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