diff --git a/src/proto_alpha/lib_protocol/script_ir_translator.ml b/src/proto_alpha/lib_protocol/script_ir_translator.ml
index dbec7e647d0f8d5c6ba9d523f522686d6a555651..44f31e8ffb33dc08bebc3bf202a08e227a865a45 100644
--- a/src/proto_alpha/lib_protocol/script_ir_translator.ml
+++ b/src/proto_alpha/lib_protocol/script_ir_translator.ml
@@ -2815,7 +2815,7 @@ and parse_instr :
         let stack_ty_after = unparse_stack_uncarbonated aft in
         log loc ~stack_ty_before ~stack_ty_after
   in
-  let typed_no_lwt ctxt loc instr aft =
+  let typed_no_lwt ctxt loc instr aft : ((a, s) judgement * context) tzresult =
     log_stack loc stack_ty aft ;
     let j = Typed {loc; instr; bef = stack_ty; aft} in
     Ok (j, ctxt)