diff --git a/src/check_ir.ml b/src/check_ir.ml
index 7f32b1d7e83..9069ae41dd4 100644
--- a/src/check_ir.ml
+++ b/src/check_ir.ml
@@ -794,7 +794,7 @@ and gather_dec env scope dec : scope =
 
 (* Programs *)
 
-let check_prog scope ((decs, flavor) as prog) : unit =
+let check_prog scope phase ((decs, flavor) as prog) : unit =
   let env = env_of_scope scope flavor in
   try
    ignore (check_block env T.unit decs no_region)
@@ -802,12 +802,12 @@ let check_prog scope ((decs, flavor) as prog) : unit =
     let bt = Printexc.get_backtrace () in
     if !Flags.verbose
     then begin
-      Printf.eprintf "Ill-typed intermediate code:\n";
+      Printf.eprintf "Ill-typed intermediate code after %s:\n" phase;
       Printf.eprintf "%s" (Wasm.Sexpr.to_string 80 (Arrange_ir.prog prog));
       Printf.eprintf "%s" s;
       Printf.eprintf "%s" bt;
     end else begin
-      Printf.eprintf "Ill-typed intermediate code (use -v to see dumped IR):\n";
+      Printf.eprintf "Ill-typed intermediate code after %s (use -v to see dumped IR):\n" phase;
       Printf.eprintf "%s" s;
       Printf.eprintf "%s" bt;
     end;
diff --git a/src/check_ir.mli b/src/check_ir.mli
index 9203122e85a..edb6264fa51 100644
--- a/src/check_ir.mli
+++ b/src/check_ir.mli
@@ -1,2 +1 @@
-val check_prog : Typing.scope -> Ir.prog -> unit
-
+val check_prog : Typing.scope -> string -> Ir.prog -> unit
diff --git a/src/pipeline.ml b/src/pipeline.ml
index d512bec7c3c..ec9fca4cb56 100644
--- a/src/pipeline.ml
+++ b/src/pipeline.ml
@@ -123,8 +123,7 @@ let transform_ir transform_name transform flag env prog name =
       phase transform_name name;
       let prog' : Ir.prog = transform prog in
       dump_ir Flags.dump_lowering prog';
-      (* Check_ir.check_prog env prog; *)
-      Check_ir.check_prog env prog';
+      Check_ir.check_prog env transform_name prog;
       prog'
     end
   else prog
@@ -292,7 +291,7 @@ let compile_with check mode name : compile_result =
     Diag.print_messages msgs;
     let prelude = Desugar.transform Typing.empty_scope prelude in
     let prog = Desugar.transform initial_stat_env prog in
-    Check_ir.check_prog initial_stat_env prog;
+    Check_ir.check_prog initial_stat_env "desugaring" prog;
     let prog = await_lowering true initial_stat_env prog name in
     let prog = async_lowering true initial_stat_env prog name in
     let prog = tailcall_optimization true initial_stat_env prog name in