{"ast_node_type":"variable","tokens":[{"end":68,"kind":"keyword","start":0,"text":"let"}]}
            let arg_ty = arg.node.ty(&caller_body.local_decls, tcx);
            let input_type = callee_body.local_decls[input].ty;
            if !util::sub_types(tcx, inliner.typing_env(), input_type, arg_ty) {