1 files changed, 1 insertions, 0 deletions
diff --git a/src/variable.c b/src/variable.c
index 5bacd5141..669a86fc2 100644
--- a/src/variable.c
+++ b/src/variable.c
@@ -419,6 +419,7 @@ obj_iv_p(mrb_value obj)
     case MRB_TT_SCLASS:
     case MRB_TT_HASH:
     case MRB_TT_DATA:
+    case MRB_TT_MAIN:
       return TRUE;
     default:
       return FALSE;