diff --git a/lib/cpu/cpu.ml b/lib/cpu/cpu.ml
index 4a97031..c3b4ab1 100644
--- a/lib/cpu/cpu.ml
+++ b/lib/cpu/cpu.ml
@@ -38,7 +38,6 @@ module Make (Bus : Word_addressable_intf.S) = struct
       ~(inst : Instruction.t) : int =
     let set_flags = Registers.set_flags t.registers in
     let read : type a. a Instruction.arg -> a = fun arg ->
-      let open Instruction in
       match arg with
       | Immediate8 n -> n
       | Immediate16 n -> n
@@ -76,7 +75,6 @@ module Make (Bus : Word_addressable_intf.S) = struct
         sp + n |> Uint16.of_int
     in
     let write : type a. a Instruction.arg -> a -> unit = fun x y ->
-      let open Instruction in
       match x with
       | R r -> Registers.write_r t.registers r y
       | RR rr -> Registers.write_rr t.registers rr y
@@ -101,9 +99,9 @@ module Make (Bus : Word_addressable_intf.S) = struct
       | Direct8 addr -> Bus.write_byte t.bus ~addr ~data:y
       | Direct16 addr -> Bus.write_word t.bus ~addr ~data:y
       | SP -> t.sp <- y
-      | SP_offset _   -> failwith @@ Printf.sprintf "Invalid arugment"
-      | Immediate16 _ -> failwith @@ Printf.sprintf "Invalid arugment"
-      | Immediate8 _  -> failwith @@ Printf.sprintf "Invalid arugment"
+      | SP_offset _
+      | Immediate16 _
+      | Immediate8 _ -> failwith @@ Printf.sprintf "Invalid arugment"
     in
     let (<--) x y = write x y in
     let check_condition t : Instruction.condition -> bool = function
diff --git a/lib/cpu/instruction.ml b/lib/cpu/instruction.ml
index 917ecad..7b6f13d 100644
--- a/lib/cpu/instruction.ml
+++ b/lib/cpu/instruction.ml
@@ -76,7 +76,7 @@ let show t =
   let show_arg : type a. a arg -> string = function
     | Immediate8 n   -> Uint8.show n
     | Immediate16 n  -> Uint16.show n
-    | Direct8 n      -> Printf.sprintf "(%s)" (Uint16.show n)
+    | Direct8 n
     | Direct16 n     -> Printf.sprintf "(%s)" (Uint16.show n)
     | R r            -> Registers.show_r r
     | RR rr          -> Registers.show_rr rr