flush.diff

diff --git a/compiler/driver.ml b/compiler/driver.ml
index 2dac8dc..b315a19 100644
--- a/compiler/driver.ml
+++ b/compiler/driver.ml
@@ -175,8 +175,11 @@ let driver (source_file : Pos.input_file) (debug : bool) (unstyled : bool)
             match output_file with
             | Some f ->
                 let oc = open_out f in
-                (Format.formatter_of_out_channel oc, fun _ -> close_out oc)
-            | None -> (Format.std_formatter, fun _ -> ())
+                ( Format.formatter_of_out_channel oc,
+                  fun _ ->
+                    Format.print_flush ();
+                    close_out oc )
+            | None -> (Format.std_formatter, fun _ -> Format.print_flush ())
           in
           if Option.is_some ex_scope then
             Format.fprintf fmt "%a\n" Scopelang.Print.format_scope
@@ -200,8 +203,11 @@ let driver (source_file : Pos.input_file) (debug : bool) (unstyled : bool)
             match output_file with
             | Some f ->
                 let oc = open_out f in
-                (Format.formatter_of_out_channel oc, fun _ -> close_out oc)
-            | None -> (Format.std_formatter, fun _ -> ())
+                ( Format.formatter_of_out_channel oc,
+                  fun _ ->
+                    Format.print_flush ();
+                    close_out oc )
+            | None -> (Format.std_formatter, fun _ -> Format.print_flush ())
           in
           if Option.is_some ex_scope then
             Format.fprintf fmt "%a\n"