diff --git a/src/lib/frontend/frontend.ml b/src/lib/frontend/frontend.ml
index d153284314..b69d7265c9 100644
--- a/src/lib/frontend/frontend.ml
+++ b/src/lib/frontend/frontend.ml
@@ -32,22 +32,6 @@ open Commands
 open Format
 open Options
 
-let timeout_reason_to_string = function
-  | Sat_solver_sig.Assume -> "Assume"
-  | ProofSearch -> "ProofSearch"
-  | ModelGen -> "ModelGen"
-
-let unknown_reason_to_string = function
-  | Sat_solver_sig.Incomplete -> "Incomplete"
-  | Memout -> "Memout"
-  | Steps_limit n -> Fmt.str "Step limit reached: %i" n
-  | Timeout t -> Fmt.str "Timeout:%s" (timeout_reason_to_string t)
-
-let unknown_reason_opt_to_string =
-  function
-  | None -> "Decided"
-  | Some r -> unknown_reason_to_string r
-
 module E = Expr
 module Ex = Explanation
 
diff --git a/src/lib/reasoners/sat_solver_sig.ml b/src/lib/reasoners/sat_solver_sig.ml
index 99b0ccc838..a276f6568f 100644
--- a/src/lib/reasoners/sat_solver_sig.ml
+++ b/src/lib/reasoners/sat_solver_sig.ml
@@ -42,11 +42,7 @@ type unknown_reason =
   | Memout
   | Steps_limit of int
   | Timeout of timeout_reason
-
-let pp_unknown_reason ppf = function
-  | Incomplete -> Fmt.pf ppf "Incomplete"
-  | Memout -> Fmt.pf ppf "Memout"
-  | Timeout t -> Fmt.pf ppf "Timeout:%a" pp_timeout_reason t
+[@@deriving show]
 
 let pp_unknown_reason_opt ppf = function
   | None -> Fmt.pf ppf "Decided"