multiname_list_t*i=cls->interfaces;
             classinfo_t*c = classinfo_register(access, package, name, list_length(i));
-            c->flags|=FLAG_ASSET;
+            c->flags|=FLAG_BUILTIN;
 
             if(cls->flags & CLASS_FINAL)
                 c->flags |= FLAG_FINAL;
                 v->flags |= trait->kind==TRAIT_CONST?FLAG_CONST:0;
                 m = (memberinfo_t*)v;
             }
-            m->flags |= FLAG_ASSET;
+            m->flags |= FLAG_BUILTIN;
             m->parent = 0;
         }
     }
 
 // ----------------------- assets -------------------------------------
 void registry_use(slotinfo_t*s)
 {
-    if(s->kind == INFOTYPE_CLASS) {
-       classinfo_t*c=(classinfo_t*)s;
-       if(c->assets) c->assets->used = 1;
-    } else if(s->kind == INFOTYPE_METHOD) {
-       methodinfo_t*m=(methodinfo_t*)s;
-       if(m->parent) {
-           registry_use((slotinfo_t*)m->parent);
-       }
-    } else if(s->kind == INFOTYPE_VAR) {
-       varinfo_t*v=(varinfo_t*)s;
-       if(v->parent) {
-           registry_use((slotinfo_t*)v->parent);
+    if(!s) return;
+    if(!(s->flags&FLAG_USED)) {
+       s->flags |= FLAG_USED;
+       if(s->kind == INFOTYPE_CLASS) {
+           classinfo_t*c=(classinfo_t*)s;
+           if(c->assets) c->assets->used = 1;
+           int t=0;
+           while(c->interfaces[t]) {
+               registry_use((slotinfo_t*)c->interfaces[t]);
+               t++;
+           }
+           while(c->superclass) {
+               c = c->superclass;
+               registry_use((slotinfo_t*)c);
+           }
+       } else if(s->kind == INFOTYPE_METHOD) {
+           methodinfo_t*m=(methodinfo_t*)s;
+           if(m->parent) {
+               registry_use((slotinfo_t*)m->parent);
+           }
+       } else if(s->kind == INFOTYPE_VAR) {
+           varinfo_t*v=(varinfo_t*)s;
+           if(v->parent) {
+               registry_use((slotinfo_t*)v->parent);
+           }
        }
     }
 }