{"ast_node_type":"other","tokens":[{"end":56,"kind":"keyword","start":0,"text":"if"}]}
                if !idx1.equivalent_for_indexing(idx2) {
                let hir::ExprKind::Index(_, idx2, _) = parent.kind else { return };
                    err.help("use `.split_at_mut(position)` to obtain two mutable non-overlapping sub-slices");