diff --git a/ipld/amt/benches/amt_benchmark.rs b/ipld/amt/benches/amt_benchmark.rs
index 54b5c5e7f..773e778ef 100644
--- a/ipld/amt/benches/amt_benchmark.rs
+++ b/ipld/amt/benches/amt_benchmark.rs
@@ -30,13 +30,11 @@ impl Serialize for BenchData {
 }
 
 impl<'de> Deserialize<'de> for BenchData {
-    #[allow(clippy::let_unit_value)]
     fn deserialize<D>(deserializer: D) -> Result<Self, <D as Deserializer<'de>>::Error>
     where
         D: Deserializer<'de>,
     {
-        let _s: () = Deserialize::deserialize(deserializer)?;
-
+        Deserialize::deserialize(deserializer)?;
         Ok(Self::default())
     }
 }
diff --git a/rust-toolchain b/rust-toolchain
index 07ade694b..67d1f3fd0 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly
\ No newline at end of file
+nightly-2022-05-09