1 files changed, 1 insertions, 1 deletions
diff --git a/eval.c b/eval.c
index b9643803d5..fa3ec22af5 100644
--- a/eval.c
+++ b/eval.c
@@ -454,7 +454,7 @@ rb_class_modify_check(VALUE klass)
 		goto noclass;
 	    }
 	}
-        rb_frozen_error_raise(klass, "can't modify frozen %s", desc);
+        rb_frozen_error_raise(klass, "can't modify frozen %s: %"PRIsVALUE, desc, klass);
     }
 }