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// Tests that two closures cannot simultaneously have mutable
// access to the variable, whether that mutable access be used
// for direct assignment or for taking mutable ref. Issue #6801.
fn to_fn_mut<F: FnMut()>(f: F) -> F { f }
fn a() {
let mut x = 3;
let c1 = to_fn_mut(|| x = 4);
let c2 = to_fn_mut(|| x = 5); //~ ERROR cannot borrow `x` as mutable more than once
c1;
}
fn set(x: &mut isize) {
*x = 4;
}
fn b() {
let mut x = 3;
let c1 = to_fn_mut(|| set(&mut x));
let c2 = to_fn_mut(|| set(&mut x)); //~ ERROR cannot borrow `x` as mutable more than once
c1;
}
fn c() {
let mut x = 3;
let c1 = to_fn_mut(|| x = 5);
let c2 = to_fn_mut(|| set(&mut x)); //~ ERROR cannot borrow `x` as mutable more than once
c1;
}
fn d() {
let mut x = 3;
let c1 = to_fn_mut(|| x = 5);
let c2 = to_fn_mut(|| { let _y = to_fn_mut(|| set(&mut x)); }); // (nested closure)
//~^ ERROR cannot borrow `x` as mutable more than once
c1;
}
fn g() {
struct Foo {
f: Box<isize>
}
let mut x: Box<_> = Box::new(Foo { f: Box::new(3) });
let c1 = to_fn_mut(|| set(&mut *x.f));
let c2 = to_fn_mut(|| set(&mut *x.f));
//~^ ERROR cannot borrow `x` as mutable more than once
c1;
}
fn main() {
}
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