diff --git a/cohttp/src/s.ml b/cohttp/src/s.ml
index dbf59ebda..1331f8018 100644
--- a/cohttp/src/s.ml
+++ b/cohttp/src/s.ml
@@ -144,8 +144,8 @@ module type Response = sig
   val version : t -> Code.version
   val status : t -> Code.status_code
 
-  val flush :
-    (t -> bool[@deprecated "this field will be removed in the future"])
+  val flush : (t -> bool)
+  [@@deprecated "this field will be removed in the future"]
 
   val compare : t -> t -> int
 
diff --git a/http/src/http.mli b/http/src/http.mli
index 82f5d1ef9..3beb0027d 100644
--- a/http/src/http.mli
+++ b/http/src/http.mli
@@ -465,10 +465,10 @@ module Response : sig
   val status : t -> Status.t
 
   val flush :
-    (t -> bool
-    [@deprecated
-      "this field will be removed in the future. Provide flush in the \
-       [respond_*] function instead."])
+    (t -> bool)
+  [@@deprecated
+    "this field will be removed in the future. Provide flush in the \
+     [respond_*] function instead."]
 
   val compare : t -> t -> int