diff --git a/src/core/CCChar.mli b/src/core/CCChar.mli
index ab1a1b5f..974e9096 100644
--- a/src/core/CCChar.mli
+++ b/src/core/CCChar.mli
@@ -4,7 +4,7 @@
 
     @since 0.14 *)
 
-include module type of Char
+include module type of struct include Char end
 
 val equal : t -> t -> bool
 (** The equal function for chars. *)
diff --git a/src/core/CCRandom.mli b/src/core/CCRandom.mli
index 7d173711..b9c55a5c 100644
--- a/src/core/CCRandom.mli
+++ b/src/core/CCRandom.mli
@@ -3,7 +3,7 @@
 
 (** {1 Random Generators} *)
 
-include module type of Random
+include module type of struct include Random end
 
 type state = Random.State.t
 
diff --git a/src/core/CCResult.mli b/src/core/CCResult.mli
index 754a215b..4f402d4a 100644
--- a/src/core/CCResult.mli
+++ b/src/core/CCResult.mli
@@ -14,7 +14,7 @@ type 'a printer = Format.formatter -> 'a -> unit
 
 (** {2 Basics} *)
 
-include module type of Result
+include module type of struct include Result end
 (** @since 1.5 *)
 
 type (+'good, +'bad) t = ('good, 'bad) Result.result =
diff --git a/src/core/CCString.mli b/src/core/CCString.mli
index a7da7a5f..1a551de0 100644
--- a/src/core/CCString.mli
+++ b/src/core/CCString.mli
@@ -60,7 +60,7 @@ end
 
 (** {2 Strings} *)
 
-include module type of String
+include module type of struct include String end
 
 val equal : string -> string -> bool
 (** Equality function on strings. *)