1 files changed, 29 insertions, 4 deletions

diff --git a/src/kernel.c b/src/kernel.c
index d1e10a7f8..225f7fa54 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -240,14 +240,12 @@ mrb_singleton_class_clone(mrb_state *mrb, mrb_value obj)
     /* copy singleton(unnamed) class */
     struct RClass *clone = (struct RClass*)mrb_obj_alloc(mrb, klass->tt, mrb->class_class);
 
-    if ((mrb_type(obj) == MRB_TT_CLASS) ||
-      (mrb_type(obj) == MRB_TT_SCLASS)) { /* BUILTIN_TYPE(obj) == T_CLASS */
+    if ((mrb_type(obj) == MRB_TT_CLASS) || (mrb_type(obj) == MRB_TT_SCLASS)) {
       clone->c = clone;
     }
     else {
       clone->c = mrb_singleton_class_clone(mrb, mrb_obj_value(klass));
     }
-
     clone->super = klass->super;
     if (klass->iv) {
       mrb_iv_copy(mrb, mrb_obj_value(clone), mrb_obj_value(klass));
@@ -269,6 +267,21 @@ copy_class(mrb_state *mrb, mrb_value dst, mrb_value src)
 {
   struct RClass *dc = mrb_class_ptr(dst);
   struct RClass *sc = mrb_class_ptr(src);
+  /* if the origin is not the same as the class, then the origin and
+     the current class need to be copied */
+  if (sc->flags & MRB_FLAG_IS_PREPENDED) {
+    struct RClass *c0 = sc->super;
+    struct RClass *c1 = dc;
+
+    /* copy prepended iclasses */
+    while (!(c0->flags & MRB_FLAG_IS_ORIGIN)) {
+      c1->super = mrb_class_ptr(mrb_obj_dup(mrb, mrb_obj_value(c0)));
+      c1 = c1->super;
+      c0 = c0->super;
+    }
+    c1->super = mrb_class_ptr(mrb_obj_dup(mrb, mrb_obj_value(c0)));
+    c1->super->flags |= MRB_FLAG_IS_ORIGIN;
+  }
   dc->mt = kh_copy(mt, mrb, sc->mt);
   dc->super = sc->super;
 }
@@ -330,6 +343,9 @@ mrb_obj_clone(mrb_state *mrb, mrb_value self)
   if (mrb_immediate_p(self)) {
     mrb_raisef(mrb, E_TYPE_ERROR, "can't clone %S", self);
   }
+  if (mrb_type(self) == MRB_TT_SCLASS) {
+    mrb_raise(mrb, E_TYPE_ERROR, "can't clone singleton class");
+  }
   p = (struct RObject*)mrb_obj_alloc(mrb, mrb_type(self), mrb_obj_class(mrb, self));
   p->c = mrb_singleton_class_clone(mrb, self);
   clone = mrb_obj_value(p);
@@ -366,6 +382,9 @@ mrb_obj_dup(mrb_state *mrb, mrb_value obj)
   if (mrb_immediate_p(obj)) {
     mrb_raisef(mrb, E_TYPE_ERROR, "can't dup %S", obj);
   }
+  if (mrb_type(obj) == MRB_TT_SCLASS) {
+    mrb_raise(mrb, E_TYPE_ERROR, "can't dup singleton class");
+  }
   p = mrb_obj_alloc(mrb, mrb_type(obj), mrb_obj_class(mrb, obj));
   dup = mrb_obj_value(p);
   init_copy(mrb, dup, obj);
@@ -635,13 +654,19 @@ mrb_class_instance_method_list(mrb_state *mrb, mrb_bool recur, struct RClass* kl
 {
   khint_t i;
   mrb_value ary;
+  mrb_bool prepended;
   struct RClass* oldklass;
   khash_t(st)* set = kh_init(st, mrb);
 
+  if (!recur && (klass->flags & MRB_FLAG_IS_PREPENDED)) {
+    MRB_CLASS_ORIGIN(klass);
+    prepended = 1;
+  }
+
   oldklass = 0;
   while (klass && (klass != oldklass)) {
     method_entry_loop(mrb, klass, set);
-    if ((klass->tt == MRB_TT_ICLASS) ||
+    if ((klass->tt == MRB_TT_ICLASS && !prepended) ||
         (klass->tt == MRB_TT_SCLASS)) {
     }
     else {