error[E0594]: cannot assign to `x`, as it is a captured variable in a `Fn` closure
  --> $DIR/borrow-immutable-upvar-mutation.rs:15:27
   |
LL | fn to_fn<A,F:Fn<A>>(f: F) -> F { f }
   |                        - change this to accept `FnMut` instead of `Fn`
...
LL |         let _f = to_fn(|| x = 42);
   |                  -----    ^^^^^^ cannot assign
   |                  |
   |                  expects `Fn` instead of `FnMut`

error[E0596]: cannot borrow `y` as mutable, as it is a captured variable in a `Fn` closure
  --> $DIR/borrow-immutable-upvar-mutation.rs:18:31
   |
LL | fn to_fn<A,F:Fn<A>>(f: F) -> F { f }
   |                        - change this to accept `FnMut` instead of `Fn`
...
LL |         let _g = to_fn(|| set(&mut y));
   |                  -----        ^^^^^^ cannot borrow as mutable
   |                  |
   |                  expects `Fn` instead of `FnMut`

error[E0594]: cannot assign to `z`, as it is a captured variable in a `Fn` closure
  --> $DIR/borrow-immutable-upvar-mutation.rs:23:22
   |
LL | fn to_fn<A,F:Fn<A>>(f: F) -> F { f }
   |                        - change this to accept `FnMut` instead of `Fn`
...
LL |             to_fn(|| z = 42);
   |             -----    ^^^^^^ cannot assign
   |             |
   |             expects `Fn` instead of `FnMut`

error[E0594]: cannot assign to `x`, as it is a captured variable in a `Fn` closure
  --> $DIR/borrow-immutable-upvar-mutation.rs:30:32
   |
LL | fn to_fn<A,F:Fn<A>>(f: F) -> F { f }
   |                        - change this to accept `FnMut` instead of `Fn`
...
LL |         let _f = to_fn(move || x = 42);
   |                  -----         ^^^^^^ cannot assign
   |                  |
   |                  expects `Fn` instead of `FnMut`

error[E0596]: cannot borrow `y` as mutable, as it is a captured variable in a `Fn` closure
  --> $DIR/borrow-immutable-upvar-mutation.rs:33:36
   |
LL | fn to_fn<A,F:Fn<A>>(f: F) -> F { f }
   |                        - change this to accept `FnMut` instead of `Fn`
...
LL |         let _g = to_fn(move || set(&mut y));
   |                  -----             ^^^^^^ cannot borrow as mutable
   |                  |
   |                  expects `Fn` instead of `FnMut`

error[E0594]: cannot assign to `z`, as it is a captured variable in a `Fn` closure
  --> $DIR/borrow-immutable-upvar-mutation.rs:36:65
   |
LL | fn to_fn<A,F:Fn<A>>(f: F) -> F { f }
   |                        - change this to accept `FnMut` instead of `Fn`
...
LL |         let _h = to_fn_mut(move || { set(&mut z); to_fn(move || z = 42); });
   |                                                   -----         ^^^^^^ cannot assign
   |                                                   |
   |                                                   expects `Fn` instead of `FnMut`

error[E0594]: cannot assign to `x`, as it is a captured variable in a `Fn` closure
  --> $DIR/borrow-immutable-upvar-mutation.rs:43:9
   |
LL |   fn foo() -> Box<dyn Fn() -> usize> {
   |      ---      ---------------------- ...to return `FnMut` instead of `Fn`
   |      |
   |      you might have to change this...
LL |       let mut x = 0;
LL |       Box::new(move || {
   |  ______________-
LL | |         x += 1;
   | |         ^^^^^^ cannot assign
LL | |         x
LL | |     })
   | |_____- in this closure

error[E0594]: cannot assign to `x`, as it is a captured variable in a `Fn` closure
  --> $DIR/borrow-immutable-upvar-mutation.rs:51:9
   |
LL |   fn bar() -> impl Fn() -> usize {
   |      ---      ------------------ ...to return `FnMut` instead of `Fn`
   |      |
   |      you might have to change this...
LL |       let mut x = 0;
LL | /     move || {
LL | |         x += 1;
   | |         ^^^^^^ cannot assign
LL | |         x
LL | |     }
   | |_____- in this closure

error: aborting due to 8 previous errors

Some errors have detailed explanations: E0594, E0596.
For more information about an error, try `rustc --explain E0594`.