{"ast_node_type":"variable","tokens":[{"end":33,"kind":"keyword","start":0,"text":"let"}]}
        let tcx = self.infcx.tcx;
    fn defining_ty(&self) -> DefiningTy<'tcx> {
        let typeck_root_def_id = tcx.typeck_root_def_id(self.mir_def.to_def_id());