{"ast_node_type":"other","tokens":[{"end":65,"kind":"keyword","start":0,"text":"call_caps.extend(upvars.keys().map(|var_id|"}]}
                    call_caps.extend(upvars.keys().map(|var_id| {
                if let Some(upvars) = self.tcx.upvars_mentioned(closure.def_id) {
                        let upvar = upvars[var_id];