{"ast_node_type":"other","tokens":[{"end":60,"kind":"keyword","start":0,"text":"//"}]}
    // as they are part of the same "inference environment".
    // Closures' typeck results come from their outermost function,
    let typeck_root_def_id = tcx.typeck_root_def_id(def_id.to_def_id()).expect_local();