diff -urNp labltk-8.06.10-orig/browser/typecheck.ml labltk-8.06.10-dwok/browser/typecheck.ml
--- labltk-8.06.10-orig/browser/typecheck.ml	2020-08-25 07:50:47.000000000 +0200
+++ labltk-8.06.10-dwok/browser/typecheck.ml	2021-02-26 01:55:00.000000000 +0100
@@ -116,7 +116,7 @@ let f txt =
     List.iter psl ~f:
     begin function
       Ptop_def pstr ->
-        let str, sign, _names, env' = Typemod.type_structure !env pstr in
+        let str, sign, _names, env' = Typemod.type_structure !env pstr Location.none in
         txt.structure <- txt.structure @ str.str_items;
         txt.signature <- txt.signature @ sign;
         env := env'