error[E0501]: cannot borrow `*f` as mutable because previous closure requires unique access --> $DIR/borrowck-insert-during-each.rs:16:5 | LL | f.foo( | ^ --- first borrow later used by call | _____| | | LL | | LL | | |a| { | | --- closure construction occurs here LL | | f.n.insert(*a); | | --- first borrow occurs due to use of `f` in closure LL | | }) | |__________^ second borrow occurs here error[E0500]: closure requires unique access to `f` but it is already borrowed --> $DIR/borrowck-insert-during-each.rs:18:9 | LL | f.foo( | - --- first borrow later used by call | | | borrow occurs here LL | LL | |a| { | ^^^ closure construction occurs here LL | f.n.insert(*a); | --- second borrow occurs due to use of `f` in closure error: aborting due to 2 previous errors Some errors have detailed explanations: E0500, E0501. For more information about an error, try `rustc --explain E0500`.