{"ast_node_type":"other","tokens":[{"end":78,"kind":"keyword","start":0,"text":"///"}]}
    /// and records a coercion predicate. Presently, this method is equivalent
    /// invoked when `FnCtxt::coerce` encounters unresolved type variables
    /// to `subtype_predicate` -- that is, "coercing" `a` to `b` winds up