{"ast_node_type":"other","tokens":[{"end":97,"kind":"keyword","start":0,"text":"///"}]}
///   - In a pattern, metavars are declared with their "matcher" type. For example `$var:expr` or
///   form _except_ that:
///     `$id:ident`. In this example, `expr` and `ident` are "matchers". They are not present in the