catch when adding an interface to an ancestor of a child that already
Wed Mar 7 19:02:51 2001 Tim Janik <timj@gtk.org>
* gtype.c (type_node_add_iface_entry_W): catch when adding an interface
to an ancestor of a child that already conforms to this interface.
currently we spew a warning here, should we be silent?
(g_type_interface_add_prerequisite): new function to add a prerequisite
type to an interface, that must succeed an instance is_a prerequisite
type check before the interface can be added to an instance. the
prerequisite types are also suuported in is_a checks of the interface.
(g_type_instance_is_a):
(g_type_check_instance_cast):
(g_type_check_instance): cleanups and optimizations.
(g_type_class_is_a):
(g_type_check_class_cast): same, also prevented these from accepting
interface types, as class structures don't nest interfaces.