1 files changed, 2 insertions, 0 deletions
diff --git a/ruby.c b/ruby.c
index c9dd782285..b2b2c690ff 100644
--- a/ruby.c
+++ b/ruby.c
@@ -865,7 +865,9 @@ debug_option(const char *str, int len, void *arg)
     static const char list[] = EACH_DEBUG_FEATURES(LITERAL_NAME_ELEMENT, ", ");
 #define SET_WHEN_DEBUG(bit) SET_WHEN(#bit, DEBUG_BIT(bit), str, len)
     EACH_DEBUG_FEATURES(SET_WHEN_DEBUG, ;);
+#ifdef RUBY_DEVEL
     if (ruby_patchlevel < 0 && ruby_env_debug_option(str, len, 0)) return;
+#endif
     rb_warn("unknown argument for --debug: `%.*s'", len, str);
     rb_warn("debug features are [%.*s].", (int)strlen(list), list);
 }