Fix issue #20. When the Top of a kind is present without variables, we

distribute it (redudantly) under all variables to simplify their pretty-printing.

Hence, instead of having e.g. :

('a \ (Int)) | Char | Int | Atom)

we have
('a | Char | Int | Atom)

types/types.ml

@@ -1849,6 +1849,31 @@ struct
         fill_line (module BoolPair) h (fun t -> t.arrow) (fun t u -> {t with arrow = u }) d;
         fill_line (module BoolRec) h (fun t -> t.record) (fun t u -> {t with record = u }) d;
         fill_line (module BoolAbstracts) h (fun t -> t.abstract) (fun t u -> {t with abstract = u }) d;
+        let h =
+          try
+            let no_var = VarTable.find h Var.Set.(empty,empty) in
+            let update_field (type s) (module BV : BoolVar.S with type t = s) get set d1 d2 =
+              let bdd = get d1 in
+              if BV.(is_empty (diff full bdd)) then set d2 bdd else d2
+            in
+            let h' = VarTable.create 17 in
+            VarTable.iter (fun ((v1, v2) as k) t ->
+              let t =
+              if Var.Set.(is_empty v1 && is_empty v2) then t
+              else
+                let t = update_field (module BoolIntervals) (fun t -> t.ints) (fun t u -> {t with ints = u }) no_var t in
+                let t = update_field (module BoolChars) (fun t -> t.chars) (fun t u -> {t with chars = u }) no_var t in
+                let t = update_field (module BoolAtoms) (fun t -> t.atoms) (fun t u -> {t with atoms = u }) no_var t in
+                let t = update_field (module BoolPair) (fun t -> t.times) (fun t u -> {t with times = u }) no_var t in
+                let t = update_field (module BoolPair) (fun t -> t.xml) (fun t u -> {t with xml = u }) no_var t in
+                let t = update_field (module BoolPair) (fun t -> t.arrow) (fun t u -> {t with arrow = u }) no_var t in
+                let t = update_field (module BoolRec) (fun t -> t.record) (fun t u -> {t with record = u }) no_var t in
+                let t = update_field (module BoolAbstracts) (fun t -> t.abstract) (fun t u -> {t with abstract = u }) no_var t in t
+              in
+              VarTable.replace h' k t
+            ) h; h'
+          with Not_found -> h
+        in
         let found_any, all_descrs =
           try
             let res =