f Pull out one callback into dedicated variable

lightning/src/ln/onion_utils.rs

@@ -482,8 +482,7 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 	const UPDATE: u16 = 0x1000;
 
 	// Handle packed channel/node updates for passing back for the route handler
-	construct_onion_keys_callback(secp_ctx, &path, session_priv,
-		|shared_secret, _, _, route_hop_opt, route_hop_idx|
+	let callback = |shared_secret, _, _, route_hop_opt: Option<&RouteHop>, route_hop_idx|
 	{
 		if res.is_some() { return; }
 
@@ -725,7 +724,11 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 		} else {
 			log_info!(logger, "Onion Error[from {}: {}({:#x})] {}", route_hop.pubkey, title, error_code, description);
 		}
-	}).expect("Route that we sent via spontaneously grew invalid keys in the middle of it?");
+	};
+
+	construct_onion_keys_callback(secp_ctx, &path, session_priv, callback)
+		.expect("Route that we sent via spontaneously grew invalid keys in the middle of it?");
+
 	if let Some(FailureLearnings {
 		network_update, short_channel_id, payment_failed_permanently, failed_within_blinded_path
 	}) = res {