{"ast_node_type":"impl","tokens":[{"end":91,"kind":"keyword","start":0,"text":"//"}]}
    // `opaque_ty_node_id`: `NodeId` of the opaque `impl Trait` type that should be created
    // `fn_node_id`: `NodeId` of the parent function (used to create child impl trait definition)
    #[instrument(level = "debug", skip(self))]