Do not generate any constraint (even trivial ones) for monomorphic variables.

types/types.ml

@@ -2791,12 +2791,13 @@ module Tallying = struct
           with
             Not_found -> inf, sup
         in
-        if Var.Set.mem v delta then
-          if ((equal inf empty) && (equal sup any)) || 
+        if Var.Set.mem v delta then map
+          (* if ((equal inf empty) && (equal sup any)) ||
              (equal (var v) inf && equal (var v) sup) then
                map
           else
             raise (UnSatConstr (Format.sprintf "%s is a monomorphic variable" (Utils.string_of_formatter Var.pp v)))
+          *)
         else
           VarMap.add v (new_i, new_s) map
 
@@ -2945,14 +2946,14 @@ module Tallying = struct
     let singleton delta = function
       |Pos (v,s) ->
           if Var.Set.mem v delta then
-            if equal s any || equal (var v) s then S.singleton M.empty
-            else raise (UnSatConstr (Format.sprintf "%s is a monomorphic variable" (Utils.string_of_formatter Var.pp v)))
+            (*if equal s any || equal (var v) s then *)S.singleton M.empty
+          (*else raise (UnSatConstr (Format.sprintf "%s is a monomorphic variable" (Utils.string_of_formatter Var.pp v))) *)
           else
             S.singleton (M.singleton v (empty,s))
       |Neg (s,v) ->
           if Var.Set.mem v delta then
-            if equal s any || equal (var v) s then S.singleton M.empty
-            else raise (UnSatConstr (Format.sprintf "%s is a monomorphic variable" (Utils.string_of_formatter Var.pp v)))
+            (*if equal s any || equal (var v) s then *)S.singleton M.empty
+          (*else raise (UnSatConstr (Format.sprintf "%s is a monomorphic variable" (Utils.string_of_formatter Var.pp v))) *)
           else
             S.singleton (M.singleton v (s,any))