{"ast_node_type":"other","tokens":[{"end":88,"kind":"keyword","start":0,"text":"//"}]}
// which would panic since it's already being mutably borrowed in the outer constructor.
// and the inner constructor would try to take a mutable borrow of the mappings `RefCell`,
fn iterator_input<N: AstNode>(input: impl IntoIterator<Item = N>) -> (Vec<N>, Vec<SyntaxNode>) {