1 files changed, 1 insertions, 0 deletions
diff --git a/eval.c b/eval.c
index 0e1b2801bf..0f21a3636f 100644
--- a/eval.c
+++ b/eval.c
@@ -9392,6 +9392,7 @@ rb_mod_define_method(argc, argv, mod)
 	noex = NOEX_PUBLIC;
     }
     rb_add_method(mod, id, node, noex);
+    rb_define_method(rb_cBinding, "dup", proc_dup, 0);
     return body;
 }