Basic example with disabling warnings

ocaml/testsuite/tests/typing-layouts/erasable_annot.ml

@@ -481,3 +481,26 @@ external f_4 : M3.t -> M3.t = "%identity" [@@unboxed]
 module M3 : sig type t = private float# end
 external f_4 : M3.t -> M3.t = "%identity" [@@unboxed]
 |}];;
+
+(* Disabling warnings *)
+
+module M4 : sig
+  [@@@warning "-187"]
+  type ('a : immediate) t = Something of 'a
+
+  val f : ('a : immediate). 'a t -> 'a
+end = struct
+  [@@@warning "-187"]
+
+  type ('a : immediate) t = Something of 'a
+
+  let f (Something x) = x
+end;;
+
+[%%expect{|
+module M4 :
+  sig
+    type ('a : immediate) t = Something of 'a
+    val f : ('a : immediate). 'a t -> 'a
+  end
+|}]