diff --git a/lib/racc/statetransitiontable.rb b/lib/racc/statetransitiontable.rb
index cae411c9..d75fa165 100644
--- a/lib/racc/statetransitiontable.rb
+++ b/lib/racc/statetransitiontable.rb
@@ -216,7 +216,7 @@ def mkmapexp(arr)
         end
         i = ii
       end
-      Regexp.compile(map, nil, 'n')
+      Regexp.compile(map, Regexp::NOENCODING)
     end
 
     def set_table(entries, dummy, tbl, chk, ptr)