diff --git a/theories/examples/sort.v b/theories/examples/sort.v
index 9a3883958369373fa5b5b8207fc8e4644214d918..1cd272b9c41656de834ca4acbcc1830b76a1c042 100644
--- a/theories/examples/sort.v
+++ b/theories/examples/sort.v
@@ -143,6 +143,7 @@ Section sort.
     wp_apply (start_chan_proto_spec sort_protocol_func); iIntros (c) "Hc".
     { rewrite -(right_id END%proto _ (iProto_dual _)).
       wp_apply (sort_service_func_spec with "Hc"); auto. }
+    (* TODO: This needs explicit (A I R) after Coq 8.10. Figure out why *)
     wp_send (A I R) with "[$Hcmp]".
     wp_send with "[$Hl]".
     wp_recv (ys) as "(Hsorted & Hperm & Hl)".