1 error[E0596]: cannot borrow `*x.1` as mutable, as it is behind a `&` reference
2 --> $DIR/issue-61623.rs:6:19
4 LL | fn f3<'a>(x: &'a ((), &'a mut ())) {
5 | -------------------- help: consider changing this to be a mutable reference: `&'a mut ((), &'a mut ())`
6 LL | f2(|| x.0, f1(x.1))
7 | ^^^ `x` is a `&` reference, so the data it refers to cannot be borrowed as mutable
9 error[E0502]: cannot borrow `*x.1` as mutable because it is also borrowed as immutable
10 --> $DIR/issue-61623.rs:6:19
12 LL | f2(|| x.0, f1(x.1))
13 | -- -- --- ^^^ mutable borrow occurs here
15 | | | first borrow occurs due to use of `x` in closure
16 | | immutable borrow occurs here
17 | immutable borrow later used by call
19 error: aborting due to 2 previous errors
21 Some errors have detailed explanations: E0502, E0596.
22 For more information about an error, try `rustc --explain E0502`.