prepare metaclass of metaclass when retrieving by singleton_class(); close #540

src/class.c

@@ -64,26 +64,38 @@ mrb_name_class(mrb_state *mrb, struct RClass *c, mrb_sym name)
                  mrb_intern(mrb, "__classid__"), mrb_symbol_value(name));
 }
 
+#define make_metaclass(mrb, c) prepare_singleton_class((mrb), (struct RBasic*)(c))
+
 static void
-make_metaclass(mrb_state *mrb, struct RClass *c)
+prepare_singleton_class(mrb_state *mrb, struct RBasic *o)
 {
-  struct RClass *sc;
+  struct RClass *sc, *c;
 
-  if (c->c->tt == MRB_TT_SCLASS) {
-    return;
-  }
+  if (o->c->tt == MRB_TT_SCLASS) return;
   sc = (struct RClass*)mrb_obj_alloc(mrb, MRB_TT_SCLASS, mrb->class_class);
   sc->mt = 0;
   sc->iv = 0;
-  if (!c->super) {
-    sc->super = mrb->class_class;
+  if (o->tt == MRB_TT_CLASS) {
+    c = (struct RClass*)o;
+    if (!c->super) {
+      sc->super = mrb->class_class;
+    }
+    else {
+      sc->super = c->super->c;
+    }
   }
-  else {
+  else if (o->tt == MRB_TT_SCLASS) {
+    c = (struct RClass*)o;
+    make_metaclass(mrb, c->super);
     sc->super = c->super->c;
   }
-  c->c = sc;
-  mrb_field_write_barrier(mrb, (struct RBasic*)c, (struct RBasic*)sc);
-  mrb_field_write_barrier(mrb, (struct RBasic*)sc, (struct RBasic*)sc->super);
+  else {
+    sc->super = o->c;
+  }
+  o->c = sc;
+  mrb_field_write_barrier(mrb, (struct RBasic*)o, (struct RBasic*)sc);
+  mrb_field_write_barrier(mrb, (struct RBasic*)sc, (struct RBasic*)o);
+  mrb_obj_iv_set(mrb, (struct RObject*)sc, mrb_intern(mrb, "__attached__"), mrb_obj_value(o));
 }
 
 struct RClass*
@@ -179,7 +191,6 @@ mrb_vm_define_class(mrb_state *mrb, mrb_value outer, mrb_value super, mrb_sym id
         mrb_raisef(mrb, E_TYPE_ERROR, "superclass mismatch for class %s", mrb_sym2name(mrb, id));
       }
     }
-
     return c;
   }
 
@@ -759,20 +770,6 @@ mrb_mod_included_modules(mrb_state *mrb, mrb_value self)
   return result;
 }
 
-static struct RClass *
-mrb_singleton_class_ptr(mrb_state *mrb, struct RClass *c)
-{
-  struct RClass *sc;
-
-  if (o->c->tt == MRB_TT_SCLASS) return;
-  sc = (struct RClass*)mrb_obj_alloc(mrb, MRB_TT_SCLASS, mrb->class_class);
-  sc->mt = 0;
-  sc->super = c;
-  mrb_field_write_barrier(mrb, (struct RBasic*)sc, (struct RBasic*)c);
-
-  return sc;
-}
-
 mrb_value
 mrb_singleton_class(mrb_state *mrb, mrb_value v)
 {
@@ -796,14 +793,14 @@ mrb_singleton_class(mrb_state *mrb, mrb_value v)
     break;
   }
   obj = mrb_object(v);
-  obj->c = mrb_singleton_class_ptr(mrb, obj->c);
+  prepare_singleton_class(mrb, obj);
   return mrb_obj_value(obj->c);
 }
 
 void
 mrb_define_singleton_method(mrb_state *mrb, struct RObject *o, const char *name, mrb_func_t func, int aspec)
 {
-  o->c = mrb_singleton_class_ptr(mrb, o->c);
+  prepare_singleton_class(mrb, (struct RBasic*)o);
   mrb_define_method_id(mrb, o->c, mrb_intern(mrb, name), func, aspec);
 }
 
@@ -944,15 +941,14 @@ mrb_value
 mrb_class_superclass(mrb_state *mrb, mrb_value klass)
 {
   struct RClass *c;
-  mrb_value superclass;
 
   c = mrb_class_ptr(klass);
-  if (c->super)
-    superclass = mrb_obj_value(mrb_class_real(c->super));
-  else
-    superclass = mrb_nil_value();
-
-  return superclass;
+  c = c->super;
+  while (c && c->tt == MRB_TT_ICLASS) {
+    c = c->super;
+  }
+  if (!c) return mrb_nil_value();
+  return mrb_obj_value(c);
 }
 
 static mrb_value

src/kernel.c

@@ -287,7 +287,8 @@ mrb_singleton_class_clone(mrb_state *mrb, mrb_value obj)
 
     clone->super = klass->super;
     if (klass->iv) {
-      clone->iv = klass->iv;
+      mrb_iv_copy(mrb, mrb_obj_value(clone), mrb_obj_value(klass));
+      mrb_obj_iv_set(mrb, (struct RObject*)clone, mrb_intern(mrb, "__attached__"), obj);
     }
     if (klass->mt) {
       clone->mt = kh_copy(mt, mrb, klass->mt);