diff --git a/src/backend/utils/adt/array_userfuncs.c b/src/backend/utils/adt/array_userfuncs.c
index e6c1f58ae0..8da3e0ac5b 100644
--- a/src/backend/utils/adt/array_userfuncs.c
+++ b/src/backend/utils/adt/array_userfuncs.c
@@ -455,7 +455,10 @@ array_cat(PG_FUNCTION_ARGS)
 
 
 /*
- * used by text_to_array() in varlena.c
+ * create_singleton_array - make a one-element array
+ *
+ * If desired, the caller can ask for it to be higher than one-dimensional.
+ * Caller's fcinfo must be passed in, as we use fn_extra for caching.
  */
 ArrayType *
 create_singleton_array(FunctionCallInfo fcinfo,