1 error[E0596]: cannot borrow `c` as mutable, as it is not declared as mutable
2 --> $DIR/issue-82438-mut-without-upvar.rs:27:27
4 LL | let c = |a, b, c, d| {};
5 | - help: consider changing this to be mutable: `mut c`
7 LL | A.f(participant_name, &mut c);
8 | ^^^^^^ cannot borrow as mutable
10 error: aborting due to previous error
12 For more information about this error, try `rustc --explain E0596`.