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 |         let _f = to_fn(|| x = 42);
   |                           ^^^^^^ cannot assign
   |
help: consider changing this to accept closures that implement `FnMut`
  --> $DIR/borrow-immutable-upvar-mutation.rs:15:24
   |
LL |         let _f = to_fn(|| x = 42);
   |                        ^^^^^^^^^

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 |         let _g = to_fn(|| set(&mut y));
   |                               ^^^^^^ cannot borrow as mutable
   |
help: consider changing this to accept closures that implement `FnMut`
  --> $DIR/borrow-immutable-upvar-mutation.rs:18:24
   |
LL |         let _g = to_fn(|| set(&mut y));
   |                        ^^^^^^^^^^^^^^

error[E0594]: cannot assign to `z`, as it is a captured variable in a `Fn` closure
  --> $DIR/borrow-immutable-upvar-mutation.rs:21:55
   |
LL |         let _h = to_fn_mut(|| { set(&mut z); to_fn(|| z = 42); });
   |                                                       ^^^^^^ cannot assign
   |
help: consider changing this to accept closures that implement `FnMut`
  --> $DIR/borrow-immutable-upvar-mutation.rs:21:52
   |
LL |         let _h = to_fn_mut(|| { set(&mut z); to_fn(|| z = 42); });
   |                                                    ^^^^^^^^^

error[E0594]: cannot assign to `x`, as it is a captured variable in a `Fn` closure
  --> $DIR/borrow-immutable-upvar-mutation.rs:27:32
   |
LL |         let _f = to_fn(move || x = 42);
   |                                ^^^^^^ cannot assign
   |
help: consider changing this to accept closures that implement `FnMut`
  --> $DIR/borrow-immutable-upvar-mutation.rs:27:24
   |
LL |         let _f = to_fn(move || x = 42);
   |                        ^^^^^^^^^^^^^^

error[E0596]: cannot borrow `y` as mutable, as it is a captured variable in a `Fn` closure
  --> $DIR/borrow-immutable-upvar-mutation.rs:30:36
   |
LL |         let _g = to_fn(move || set(&mut y));
   |                                    ^^^^^^ cannot borrow as mutable
   |
help: consider changing this to accept closures that implement `FnMut`
  --> $DIR/borrow-immutable-upvar-mutation.rs:30:24
   |
LL |         let _g = to_fn(move || set(&mut y));
   |                        ^^^^^^^^^^^^^^^^^^^

error[E0594]: cannot assign to `z`, as it is a captured variable in a `Fn` closure
  --> $DIR/borrow-immutable-upvar-mutation.rs:33:65
   |
LL |         let _h = to_fn_mut(move || { set(&mut z); to_fn(move || z = 42); });
   |                                                                 ^^^^^^ cannot assign
   |
help: consider changing this to accept closures that implement `FnMut`
  --> $DIR/borrow-immutable-upvar-mutation.rs:33:57
   |
LL |         let _h = to_fn_mut(move || { set(&mut z); to_fn(move || z = 42); });
   |                                                         ^^^^^^^^^^^^^^

error: aborting due to 6 previous errors

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