diff --git a/Cargo.toml b/Cargo.toml
index f7f7f1e6c4..33fa8fee91 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -120,7 +120,6 @@ checked_conversions = "allow"
 else_if_without_else = "allow"
 float_arithmetic = "allow"
 indexing_slicing = "allow"
-let_unit_value = "allow"
 match_wild_err_arm = "allow"
 multiple_inherent_impl = "allow"
 multiple_unsafe_ops_per_block = "allow"
diff --git a/src/proto/h1/role.rs b/src/proto/h1/role.rs
index fce1df78af..46312286ca 100644
--- a/src/proto/h1/role.rs
+++ b/src/proto/h1/role.rs
@@ -83,7 +83,7 @@ where
         return Ok(None);
     }
 
-    let _entered = trace_span!("parse_headers");
+    trace_span!("parse_headers");
 
     if let Some(prev_len) = prev_len {
         if !is_complete_fast(bytes, prev_len) {
@@ -124,7 +124,7 @@ pub(super) fn encode_headers<T>(
 where
     T: Http1Transaction,
 {
-    let _entered = trace_span!("encode_headers");
+    trace_span!("encode_headers");
     T::encode(enc, dst)
 }