syntax_data: {"ast_node_type":"function","tokens":[{"end":95,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn closure_env_param(&self, owner_def: LocalDefId, expr_id: HirId) -> Option<Param<'tcx>> {
context_after:         if self.tcx.def_kind(owner_def) != DefKind::Closure {