diff --git a/Modules/readline.c b/Modules/readline.c
index c79d22f85f8..1d506720907 100644
--- a/Modules/readline.c
+++ b/Modules/readline.c
@@ -1256,9 +1256,9 @@ setup_readline(readlinestate *mod_state)
     rl_attempted_completion_function = flex_complete;
     /* Set Python word break characters */
     completer_word_break_characters =
-        rl_completer_word_break_characters =
         strdup(" \t\n`~!@#$%^&*()-=+[{]}\\|;:'\",<>/?");
         /* All nonalphanums except '.' */
+    rl_completer_word_break_characters = completer_word_break_characters;
 
     mod_state->begidx = PyLong_FromLong(0L);
     mod_state->endidx = PyLong_FromLong(0L);