error[E0596]: cannot borrow data in an index of `HashMap<&str, String>` as mutable --> $DIR/index-mut-help.rs:11:5 | LL | map["peter"].clear(); | ^^^^^^^^^^^^^^^^^^^^ cannot borrow as mutable | = help: trait `IndexMut` is required to modify indexed content, but it is not implemented for `HashMap<&str, String>` error[E0594]: cannot assign to data in an index of `HashMap<&str, String>` --> $DIR/index-mut-help.rs:12:5 | LL | map["peter"] = "0".to_string(); | ^^^^^^^^^^^^ cannot assign | = help: trait `IndexMut` is required to modify indexed content, but it is not implemented for `HashMap<&str, String>` error[E0596]: cannot borrow data in an index of `HashMap<&str, String>` as mutable --> $DIR/index-mut-help.rs:13:13 | LL | let _ = &mut map["peter"]; | ^^^^^^^^^^^^^^^^^ cannot borrow as mutable | = help: trait `IndexMut` is required to modify indexed content, but it is not implemented for `HashMap<&str, String>` error: aborting due to 3 previous errors Some errors have detailed explanations: E0594, E0596. For more information about an error, try `rustc --explain E0594`.