clone Class/Module rightly

src/kernel.c

@@ -293,13 +293,23 @@ mrb_singleton_class_clone(mrb_state *mrb, mrb_value obj)
   }
 }
 
+static void
+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);
+  dc->mt = kh_copy(mt, mrb, sc->mt);
+  dc->super = sc->super;
+}
+
 static void
 init_copy(mrb_state *mrb, mrb_value dest, mrb_value obj)
 {
-    switch (mrb_type(obj)) {
-      case MRB_TT_OBJECT:
+  switch (mrb_type(obj)) {
       case MRB_TT_CLASS:
       case MRB_TT_MODULE:
+        copy_class(mrb, dest, obj);
+      case MRB_TT_OBJECT:
       case MRB_TT_SCLASS:
       case MRB_TT_HASH:
       case MRB_TT_DATA:

test/t/class.rb

@@ -359,3 +359,13 @@ assert('singleton tests') do
     end
   end
 end
+
+assert('clone Class') do
+  class Foo
+    def func
+      true
+    end
+  end
+
+  Foo.clone.new.func
+end

test/t/module.rb

@@ -503,3 +503,17 @@ assert('Issue 1467') do
   C1.new
   C2.new
 end
+
+assert('clone Module') do
+  module M1
+    def foo
+      true
+    end
+  end
+
+  class B
+    include M1.clone
+  end
+
+  B.new.foo
+end