diff --git a/serde_codegen/src/lib.rs b/serde_codegen/src/lib.rs
index 52ca7912..36bb38c0 100644
--- a/serde_codegen/src/lib.rs
+++ b/serde_codegen/src/lib.rs
@@ -2,6 +2,7 @@
 #![cfg_attr(feature = "nightly-testing", feature(plugin))]
 #![cfg_attr(feature = "nightly-testing", allow(too_many_arguments))]
 #![cfg_attr(feature = "nightly-testing", allow(used_underscore_binding))]
+#![cfg_attr(feature = "nightly-testing", allow(useless_let_if_seq))]
 #![cfg_attr(not(feature = "with-syntex"), feature(rustc_private, plugin))]
 #![cfg_attr(not(feature = "with-syntex"), plugin(quasi_macros))]