diff --git a/gio/gdbus-2.0/codegen/codegen.py b/gio/gdbus-2.0/codegen/codegen.py
index ee2834fb3..293b93e94 100644
--- a/gio/gdbus-2.0/codegen/codegen.py
+++ b/gio/gdbus-2.0/codegen/codegen.py
@@ -1029,6 +1029,10 @@ class CodeGenerator:
         self.write_gtkdoc_deprecated_and_since_and_close(i, self.c, 0)
         self.c.write('\n')
 
+        self.c.write('typedef %sIface %sInterface;\n'%(i.camel_name, i.camel_name))
+        self.c.write('G_DEFINE_INTERFACE (%s, %s, G_TYPE_OBJECT);\n'%(i.camel_name, i.name_lower))
+        self.c.write('\n')
+
         self.c.write('static void\n'
                      '%s_default_init (%sIface *iface)\n'
                      '{\n'%(i.name_lower, i.camel_name));
@@ -1175,10 +1179,6 @@ class CodeGenerator:
         self.c.write('}\n'
                      '\n')
 
-        self.c.write('typedef %sIface %sInterface;\n'%(i.camel_name, i.camel_name))
-        self.c.write('G_DEFINE_INTERFACE (%s, %s, G_TYPE_OBJECT);\n'%(i.camel_name, i.name_lower))
-        self.c.write('\n')
-
     # ----------------------------------------------------------------------------------------------------
 
     def generate_property_accessors(self, i):
@@ -2660,6 +2660,9 @@ class CodeGenerator:
                 %(self.namespace, self.namespace), False))
         self.c.write('\n')
 
+        self.c.write('typedef %sObjectIface %sObjectInterface;\n'%(self.namespace, self.namespace))
+        self.c.write('G_DEFINE_INTERFACE_WITH_CODE (%sObject, %sobject, G_TYPE_OBJECT, g_type_interface_add_prerequisite (g_define_type_id, G_TYPE_DBUS_OBJECT));\n'%(self.namespace, self.ns_lower))
+        self.c.write('\n')
         self.c.write('static void\n'
                      '%sobject_default_init (%sObjectIface *iface)\n'
                      '{\n'
@@ -2680,10 +2683,6 @@ class CodeGenerator:
         self.c.write('}\n'
                      '\n')
 
-        self.c.write('typedef %sObjectIface %sObjectInterface;\n'%(self.namespace, self.namespace))
-        self.c.write('G_DEFINE_INTERFACE_WITH_CODE (%sObject, %sobject, G_TYPE_OBJECT, g_type_interface_add_prerequisite (g_define_type_id, G_TYPE_DBUS_OBJECT));\n'%(self.namespace, self.ns_lower))
-        self.c.write('\n')
-
         for i in self.ifaces:
             self.c.write(self.docbook_gen.expand(
                     '/**\n'