src/Pure/Thy/thy_load.ML

 fun deps_thy dir name =
   let
     val master as (path, _) = check_thy dir name;
     val text = File.read path;
     val (name', imports, uses) =
-      Thy_Header.read (Path.position path) (Source.of_list_limited 8000 (explode text));
+      Thy_Header.read (Path.position path) (Source.of_string_limited 8000 text);
     val _ = check_name name name';
     val uses = map (Path.explode o #1) uses;
   in {master = master, text = text, imports = imports, uses = uses} end;