diff --git a/string.c b/string.c
index 608d5cf7dc..dee17c86a6 100644
--- a/string.c
+++ b/string.c
@@ -3790,6 +3790,7 @@ rb_str_append_as_bytes(int argc, VALUE *argv, VALUE str)
                 if (ENC_CODERANGE(obj) != ENC_CODERANGE_7BIT) {
                     goto clear_cr;
                 }
+                break;
               }
               default:
                 UNREACHABLE;