gistfile1.diff

diff --git a/core/src/main/java/org/jruby/ext/set/RubySet.java b/core/src/main/java/org/jruby/ext/set/RubySet.java
index 85dbf33d42..5d8e0c73dd 100644
--- a/core/src/main/java/org/jruby/ext/set/RubySet.java
+++ b/core/src/main/java/org/jruby/ext/set/RubySet.java
@@ -304,16 +304,14 @@ public class RubySet extends RubyObject implements Set {
 
     @JRubyMethod
     public IRubyObject initialize_dup(ThreadContext context, IRubyObject orig) {
-        RubyClass superClass = orig.getMetaClass().getSuperClass();
-        sites(context).initialize_dup_super.call(context, this, this, superClass, "initialize_dup", orig);
+        sites(context).initialize_dup_super.call(context, this, this, context.runtime.getClassFromPath("Set"), "initialize_dup", orig);
         setHash((RubyHash) (((RubySet) orig).hash).dup(context));
         return this;
     }
 
     @JRubyMethod
     public IRubyObject initialize_clone(ThreadContext context, IRubyObject orig) {
-        RubyClass superClass = orig.getMetaClass().getSuperClass();
-        sites(context).initialize_clone_super.call(context, this, this, superClass, "initialize_clone", orig);
+        sites(context).initialize_clone_super.call(context, this, this, context.runtime.getClassFromPath("Set"), "initialize_clone", orig);
         setHash((RubyHash) (((RubySet) orig).hash).rbClone(context));
         return this;
     }