1 files changed, 2 insertions, 0 deletions
diff --git a/ractor.c b/ractor.c
index 693bbe274d..c895aab980 100644
--- a/ractor.c
+++ b/ractor.c
@@ -21,6 +21,7 @@ static VALUE rb_eRactorRemoteError;
 static VALUE rb_eRactorMovedError;
 static VALUE rb_eRactorClosedError;
 static VALUE rb_cRactorMovedObject;
+VALUE rb_eRactorUnsafeError;
 
 VALUE
 rb_ractor_error_class(void)
@@ -1670,6 +1671,7 @@ Init_Ractor(void)
     rb_eRactorRemoteError = rb_define_class_under(rb_cRactor, "RemoteError", rb_eRactorError);
     rb_eRactorMovedError  = rb_define_class_under(rb_cRactor, "MovedError",  rb_eRactorError);
     rb_eRactorClosedError = rb_define_class_under(rb_cRactor, "ClosedError", rb_eStopIteration);
+    rb_eRactorUnsafeError = rb_define_class_under(rb_cRactor, "UnsafeError", rb_eRactorError);
 
     rb_cRactorMovedObject = rb_define_class_under(rb_cRactor, "MovedObject", rb_cBasicObject);
     rb_undef_alloc_func(rb_cRactorMovedObject);