diff --git a/src/passes/4-typer/solver.ml b/src/passes/4-typer/solver.ml
index 91b6715ac..cf345b218 100644
--- a/src/passes/4-typer/solver.ml
+++ b/src/passes/4-typer/solver.ml
@@ -864,13 +864,13 @@ let compare_output_specialize1 { poly = a1; a_k_var = a2 } { poly = b1; a_k_var
 let compare_output_break_ctor { a_k_var=a1; a_k'_var'=a2 } { a_k_var=b1; a_k'_var'=b2 } =
   compare_c_constructor_simpl a1 b1 <? fun () -> compare_c_constructor_simpl a2 b2
 
-module OutputSpecialize1 : Set.OrderedType = struct
+module OutputSpecialize1 : (Set.OrderedType with type t = output_specialize1) = struct
   type t = output_specialize1
   let compare = compare_output_specialize1
 end
 
 
-module BreakCtor : Set.OrderedType = struct
+module BreakCtor : (Set.OrderedType with type t = output_break_ctor) = struct
   type t = output_break_ctor
   let compare = compare_output_break_ctor
 end
@@ -917,24 +917,24 @@ let propagator_specialize1 : output_specialize1 propagator =
 module M (BlaBla : Set.OrderedType) = struct
   module AlreadySelected = Set.Make(BlaBla)
 
-let select_and_propagate : ('old_input, 'selector_output) selector -> BlaBla.t propagator -> 'a -> structured_dbs -> new_constraints * new_assignments =
-  fun selector propagator ->
-  fun old_type_constraint dbs ->
-    (* TODO: thread some state to know which selector outputs were already seen *)
-    let already_selected = failwith "(?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? TODO)" in
-  match selector old_type_constraint dbs with
-    WasSelected selected_outputs ->
-    (* TODO: fold instead. *)
-    let selected_outputs = List.filter (fun elt -> AlreadySelected.mem elt already_selected) selected_outputs in
-    let blahblah = List.fold_left (fun acc elt -> AlreadySelected.add elt acc) already_selected selected_outputs in
-    let _______________________________________________________________________________________________________________________________________TODO = blahblah in
-    (* Call the propagation rule *)
-    let new_contraints_and_assignments = List.map (fun s -> propagator s dbs) selected_outputs in
-    let (new_constraints , new_assignments) = List.split new_contraints_and_assignments in
-    (* return so that the new constraints are pushed to some kind of work queue and the new assignments stored *)
-    (List.flatten new_constraints , List.flatten new_assignments)
-  | WasNotSelected ->
-    ([] , [])
+  let select_and_propagate : ('old_input, 'selector_output) selector -> BlaBla.t propagator -> 'a -> structured_dbs -> new_constraints * new_assignments =
+    fun selector propagator ->
+    fun old_type_constraint dbs ->
+      (* TODO: thread some state to know which selector outputs were already seen *)
+      let already_selected = failwith "(?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? TODO)" in
+      match selector old_type_constraint dbs with
+        WasSelected selected_outputs ->
+        (* TODO: fold instead. *)
+        let selected_outputs = List.filter (fun elt -> AlreadySelected.mem elt already_selected) selected_outputs in
+        let blahblah = List.fold_left (fun acc elt -> AlreadySelected.add elt acc) already_selected selected_outputs in
+        let _______________________________________________________________________________________________________________________________________TODO = blahblah in
+        (* Call the propagation rule *)
+        let new_contraints_and_assignments = List.map (fun s -> propagator s dbs) selected_outputs in
+        let (new_constraints , new_assignments) = List.split new_contraints_and_assignments in
+        (* return so that the new constraints are pushed to some kind of work queue and the new assignments stored *)
+        (List.flatten new_constraints , List.flatten new_assignments)
+      | WasNotSelected ->
+        ([] , [])
 end
 
 module M_break_ctor = M(BreakCtor)