src/Tools/Code/code_scala.ML

         val filename = case modlname
          of "" => Path.explode "Main.scala"
           | _ => (Path.ext "scala" o Path.explode o implode o separate "/"
                 o Long_Name.explode) modlname;
         val pathname = Path.append destination filename;
-        val _ = File.mkdir (Path.dir pathname);
+        val _ = File.mkdir_leaf (Path.dir pathname);
       in File.write pathname (code_of_pretty content) end
   in
     Code_Target.mk_serialization target NONE
       (fn NONE => K () o map (code_writeln o snd) | SOME file => K () o map
         (write_module (check_destination file)))