diff --git a/glib/glist.c b/glib/glist.c
index 9bc7b4c9a..8ba2f84e6 100644
--- a/glib/glist.c
+++ b/glib/glist.c
@@ -165,7 +165,7 @@ g_list_free_full (GList          *list,
 
 /**
  * g_list_append:
- * @list: a pointer to a #GList
+ * @list: (nullable): a pointer to a #GList
  * @data: the data for the new element
  *
  * Adds a new element on to the end of the list.
@@ -222,7 +222,7 @@ g_list_append (GList    *list,
 
 /**
  * g_list_prepend:
- * @list: a pointer to a #GList, this must point to the top of the list
+ * @list: (nullable): a pointer to a #GList, this must point to the top of the list
  * @data: the data for the new element
  *
  * Prepends a new element on to the start of the list.
@@ -269,7 +269,7 @@ g_list_prepend (GList    *list,
 
 /**
  * g_list_insert:
- * @list: a pointer to a #GList, this must point to the top of the list
+ * @list: (nullable): a pointer to a #GList, this must point to the top of the list
  * @data: the data for the new element
  * @position: the position to insert the element. If this is 
  *     negative, or is larger than the number of elements in the 
@@ -366,7 +366,7 @@ g_list_insert_before_link (GList *list,
 
 /**
  * g_list_insert_before:
- * @list: a pointer to a #GList, this must point to the top of the list
+ * @list: (nullable): a pointer to a #GList, this must point to the top of the list
  * @sibling: the list element before which the new element 
  *     is inserted or %NULL to insert at the end of the list
  * @data: the data for the new element
diff --git a/glib/gslist.c b/glib/gslist.c
index bec9b01e0..4ca7338ea 100644
--- a/glib/gslist.c
+++ b/glib/gslist.c
@@ -152,7 +152,7 @@ g_slist_free_full (GSList         *list,
 
 /**
  * g_slist_append:
- * @list: a #GSList
+ * @list: (nullable): a #GSList
  * @data: the data for the new element
  *
  * Adds a new element on to the end of the list.
@@ -205,7 +205,7 @@ g_slist_append (GSList   *list,
 
 /**
  * g_slist_prepend:
- * @list: a #GSList
+ * @list: (nullable): a #GSList
  * @data: the data for the new element
  *
  * Adds a new element on to the start of the list.
@@ -238,7 +238,7 @@ g_slist_prepend (GSList   *list,
 
 /**
  * g_slist_insert:
- * @list: a #GSList
+ * @list: (nullable): a #GSList
  * @data: the data for the new element
  * @position: the position to insert the element.
  *     If this is negative, or is larger than the number
@@ -289,7 +289,7 @@ g_slist_insert (GSList   *list,
 
 /**
  * g_slist_insert_before:
- * @slist: a #GSList
+ * @slist: (nullable): a #GSList
  * @sibling: node to insert @data before
  * @data: data to put in the newly-inserted node
  *