{"ast_node_type":"other","tokens":[{"end":34,"kind":"keyword","start":0,"text":"param_env:"}]}
    param_env: ty::ParamEnv<'tcx>,
    region_bound_pairs: &'a RegionBoundPairs<'tcx>,
    known_type_outlives_obligations: &'a [ty::PolyTypeOutlivesPredicate<'tcx>],