{"ast_node_type":"variable","tokens":[{"end":52,"kind":"keyword","start":0,"text":"let"}]}
                    let span = tcx.def_span(def_id);
                    let ty = tcx.type_of(def_id).instantiate_identity();
                    let item_ty = wfcx.deeply_normalize(span, Some(WellFormedLoc::Ty(def_id)), ty);