diff --git a/ext/date/date_core.c b/ext/date/date_core.c
index 7b71a647a6..fa8d673f54 100644
--- a/ext/date/date_core.c
+++ b/ext/date/date_core.c
@@ -9112,6 +9112,7 @@ mk_ary_of_str(long len, const char *a[])
     return o;
 }
 
+/* :nodoc: */
 static VALUE
 d_lite_zero(VALUE x)
 {