diff --git a/marshal.c b/marshal.c
index 958778377d..ba5e75c9a2 100644
--- a/marshal.c
+++ b/marshal.c
@@ -1878,7 +1878,8 @@ r_object0(struct load_arg *arg, int *ivp, VALUE extmod)
 
       case TYPE_DATA:
 	{
-	    VALUE klass = path2class(r_unique(arg));
+	    VALUE name = r_unique(arg);
+	    VALUE klass = path2class(name);
 	    VALUE oldclass = 0;
 	    VALUE r;
 
@@ -1889,8 +1890,8 @@ r_object0(struct load_arg *arg, int *ivp, VALUE extmod)
 	    v = r_entry(v, arg);
 	    if (!rb_obj_respond_to(v, s_load_data, TRUE)) {
 		rb_raise(rb_eTypeError,
-			 "class %s needs to have instance method `_load_data'",
-			 rb_class2name(klass));
+			 "class %"PRIsVALUE" needs to have instance method `_load_data'",
+			 name);
 	    }
 	    r = r_object0(arg, 0, extmod);
 	    rb_funcall2(v, s_load_data, 1, &r);
diff --git a/test/ruby/test_marshal.rb b/test/ruby/test_marshal.rb
index 115c6bcc5b..2a72703adc 100644
--- a/test/ruby/test_marshal.rb
+++ b/test/ruby/test_marshal.rb
@@ -661,4 +661,16 @@ class TestMarshal < Test::Unit::TestCase
       Marshal.dump(c.new)
     }
   end
+
+  def test_unloadable_data
+    c = eval("class Unloadable\u{23F0 23F3}<Time;;self;end")
+    c.class_eval {
+      alias _dump_data _dump
+      undef _dump
+    }
+    d = Marshal.dump(c.new)
+    assert_raise_with_message(TypeError, /Unloadable\u{23F0 23F3}/) {
+      Marshal.load(d)
+    }
+  end
 end