{"ast_node_type":"variable","tokens":[{"end":42,"kind":"keyword","start":0,"text":"let"}]}
        let ty_span = tcx.ty_span(def_id);
        let ty = tcx.type_of(def_id).instantiate_identity();
        let ty = wfcx.deeply_normalize(ty_span, Some(WellFormedLoc::Ty(def_id)), ty);