1 files changed, 1 insertions, 1 deletions
diff --git a/gc.c b/gc.c
index d0294cbc26..fbdc964514 100644
--- a/gc.c
+++ b/gc.c
@@ -716,7 +716,7 @@ VALUE
 rb_data_object_alloc(VALUE klass, void *datap, RUBY_DATA_FUNC dmark, RUBY_DATA_FUNC dfree)
 {
     NEWOBJ_OF(data, struct RData, klass, T_DATA);
-    Check_Type(klass, T_CLASS);
+    if (klass) Check_Type(klass, T_CLASS);
     data->data = datap;
     data->dfree = dfree;
     data->dmark = dmark;