diff --git a/core/src/identity/error.rs b/core/src/identity/error.rs
index 184305652ba..522c21e4bf0 100644
--- a/core/src/identity/error.rs
+++ b/core/src/identity/error.rs
@@ -82,6 +82,11 @@ impl DecodingError {
         }
     }
 
+    #[cfg(any(
+        all(feature = "rsa", not(target_arch = "wasm32")),
+        feature = "secp256k1",
+        feature = "ecdsa"
+    ))]
     pub(crate) fn encoding_unsupported(key_type: &'static str) -> Self {
         Self {
             msg: format!("encoding {key_type} key to Protobuf is unsupported"),
diff --git a/transports/quic/src/provider.rs b/transports/quic/src/provider.rs
index f0b53aa699d..02c8bad71cf 100644
--- a/transports/quic/src/provider.rs
+++ b/transports/quic/src/provider.rs
@@ -32,6 +32,7 @@ pub mod async_std;
 pub mod tokio;
 
 /// Size of the buffer for reading data 0x10000.
+#[cfg(any(feature = "async-io", feature = "tokio"))]
 const RECEIVE_BUFFER_SIZE: usize = 65536;
 
 /// Provider for non-blocking receiving and sending on a [`std::net::UdpSocket`]