diff --git a/gio/gdbusaddress.c b/gio/gdbusaddress.c
index 4ef7b3c25..3901b9544 100644
--- a/gio/gdbusaddress.c
+++ b/gio/gdbusaddress.c
@@ -873,7 +873,7 @@ g_dbus_address_get_stream (const gchar         *address,
 /**
  * g_dbus_address_get_stream_finish:
  * @res: A #GAsyncResult obtained from the GAsyncReadyCallback passed to g_dbus_address_get_stream().
- * @out_guid: %NULL or return location to store the GUID extracted from @address, if any.
+ * @out_guid: (optional) (out): %NULL or return location to store the GUID extracted from @address, if any.
  * @error: Return location for error or %NULL.
  *
  * Finishes an operation started with g_dbus_address_get_stream().
@@ -910,7 +910,7 @@ g_dbus_address_get_stream_finish (GAsyncResult        *res,
 /**
  * g_dbus_address_get_stream_sync:
  * @address: A valid D-Bus address.
- * @out_guid: %NULL or return location to store the GUID extracted from @address, if any.
+ * @out_guid: (optional) (out): %NULL or return location to store the GUID extracted from @address, if any.
  * @cancellable: (allow-none): A #GCancellable or %NULL.
  * @error: Return location for error or %NULL.
  *
diff --git a/gobject/gclosure.c b/gobject/gclosure.c
index 8daf5f9b4..815242413 100644
--- a/gobject/gclosure.c
+++ b/gobject/gclosure.c
@@ -755,7 +755,7 @@ g_closure_remove_finalize_notifier (GClosure      *closure,
 /**
  * g_closure_invoke:
  * @closure: a #GClosure
- * @return_value: (allow-none): a #GValue to store the return
+ * @return_value: (optional) (out): a #GValue to store the return
  *                value. May be %NULL if the callback of @closure
  *                doesn't return a value.
  * @n_param_values: the length of the @param_values array
diff --git a/gobject/gsignal.c b/gobject/gsignal.c
index 9229f44a6..03fe09f64 100644
--- a/gobject/gsignal.c
+++ b/gobject/gsignal.c
@@ -1265,7 +1265,7 @@ g_signal_lookup (const gchar *name,
  * created. Further information about the signals can be acquired through
  * g_signal_query().
  *
- * Returns: (array length=n_ids): Newly allocated array of signal IDs.
+ * Returns: (array length=n_ids) (transfer full): Newly allocated array of signal IDs.
  */
 guint*
 g_signal_list_ids (GType  itype,
diff --git a/gobject/gvaluetypes.c b/gobject/gvaluetypes.c
index 4b234a3f7..fd452fac8 100644
--- a/gobject/gvaluetypes.c
+++ b/gobject/gvaluetypes.c
@@ -1239,7 +1239,7 @@ g_value_set_variant (GValue   *value,
 /**
  * g_value_take_variant:
  * @value: a valid #GValue of type %G_TYPE_VARIANT
- * @variant: (allow-none): a #GVariant, or %NULL
+ * @variant: (nullable) (transfer full): a #GVariant, or %NULL
  *
  * Set the contents of a variant #GValue to @variant, and takes over
  * the ownership of the caller's reference to @variant;