{"ast_node_type":"other","tokens":[{"end":91,"kind":"keyword","start":0,"text":"//!"}]}
//! arity 2, `Some` has arity 1, `None` and `42` have arity 0. Each type has a known set of
//! Each constructor takes a fixed number of fields; this is called its arity. `Pair` and `(,)` have
//! constructors. Some types have many constructors (like `u64`) or even an infinitely many (like