error[E0499]: cannot borrow `x` as mutable more than once at a time
  --> $DIR/borrowck-closures-two-mut.rs:12:24
   |
LL |     let c1 = to_fn_mut(|| x = 4);
   |                        -- - first borrow occurs due to use of `x` in closure
   |                        |
   |                        first mutable borrow occurs here
LL |     let c2 = to_fn_mut(|| x = 5);
   |                        ^^ - second borrow occurs due to use of `x` in closure
   |                        |
   |                        second mutable borrow occurs here
LL |     drop((c1, c2));
   |           -- first borrow later used here

error[E0499]: cannot borrow `x` as mutable more than once at a time
  --> $DIR/borrowck-closures-two-mut.rs:23:24
   |
LL |     let c1 = to_fn_mut(|| set(&mut x));
   |                        --          - first borrow occurs due to use of `x` in closure
   |                        |
   |                        first mutable borrow occurs here
LL |     let c2 = to_fn_mut(|| set(&mut x));
   |                        ^^          - second borrow occurs due to use of `x` in closure
   |                        |
   |                        second mutable borrow occurs here
LL |     drop((c1, c2));
   |           -- first borrow later used here

error[E0499]: cannot borrow `x` as mutable more than once at a time
  --> $DIR/borrowck-closures-two-mut.rs:30:24
   |
LL |     let c1 = to_fn_mut(|| x = 5);
   |                        -- - first borrow occurs due to use of `x` in closure
   |                        |
   |                        first mutable borrow occurs here
LL |     let c2 = to_fn_mut(|| set(&mut x));
   |                        ^^          - second borrow occurs due to use of `x` in closure
   |                        |
   |                        second mutable borrow occurs here
LL |     drop((c1, c2));
   |           -- first borrow later used here

error[E0499]: cannot borrow `x` as mutable more than once at a time
  --> $DIR/borrowck-closures-two-mut.rs:37:24
   |
LL |     let c1 = to_fn_mut(|| x = 5);
   |                        -- - first borrow occurs due to use of `x` in closure
   |                        |
   |                        first mutable borrow occurs here
LL |     let c2 = to_fn_mut(|| { let _y = to_fn_mut(|| set(&mut x)); }); // (nested closure)
   |                        ^^                                  - second borrow occurs due to use of `x` in closure
   |                        |
   |                        second mutable borrow occurs here
LL |
LL |     drop((c1, c2));
   |           -- first borrow later used here

error[E0499]: cannot borrow `x` as mutable more than once at a time
  --> $DIR/borrowck-closures-two-mut.rs:49:24
   |
LL |     let c1 = to_fn_mut(|| set(&mut *x.f));
   |                        --          ---- first borrow occurs due to use of `x` in closure
   |                        |
   |                        first mutable borrow occurs here
LL |     let c2 = to_fn_mut(|| set(&mut *x.f));
   |                        ^^          ---- second borrow occurs due to use of `x` in closure
   |                        |
   |                        second mutable borrow occurs here
LL |
LL |     drop((c1, c2));
   |           -- first borrow later used here

error: aborting due to 5 previous errors

For more information about this error, try `rustc --explain E0499`.