impl BatchCallBuilder for ()

Author: svyatonik

relays/bin-substrate/src/chains/bridge_hub_rococo_messages_to_bridge_hub_wococo.rs

@@ -59,4 +59,7 @@ impl SubstrateMessageLane for BridgeHubRococoMessagesToBridgeHubWococoMessageLan
 		BridgeHubRococoMessagesToBridgeHubWococoMessageLaneReceiveMessagesProofCallBuilder;
 	type ReceiveMessagesDeliveryProofCallBuilder =
 		BridgeHubRococoMessagesToBridgeHubWococoMessageLaneReceiveMessagesDeliveryProofCallBuilder;
+
+	type SourceBatchCallBuilder = ();
+	type TargetBatchCallBuilder = ();
 }

relays/bin-substrate/src/chains/bridge_hub_wococo_messages_to_bridge_hub_rococo.rs

@@ -59,4 +59,7 @@ impl SubstrateMessageLane for BridgeHubWococoMessagesToBridgeHubRococoMessageLan
 		BridgeHubWococoMessagesToBridgeHubRococoMessageLaneReceiveMessagesProofCallBuilder;
 	type ReceiveMessagesDeliveryProofCallBuilder =
 		BridgeHubWococoMessagesToBridgeHubRococoMessageLaneReceiveMessagesDeliveryProofCallBuilder;
+
+	type SourceBatchCallBuilder = ();
+	type TargetBatchCallBuilder = ();
 }

relays/bin-substrate/src/chains/millau_messages_to_rialto.rs

@@ -41,4 +41,7 @@ impl SubstrateMessageLane for MillauMessagesToRialto {
 		millau_runtime::Runtime,
 		millau_runtime::WithRialtoMessagesInstance,
 	>;
+
+	type SourceBatchCallBuilder = ();
+	type TargetBatchCallBuilder = ();
 }

relays/bin-substrate/src/chains/millau_messages_to_rialto_parachain.rs

@@ -41,4 +41,7 @@ impl SubstrateMessageLane for MillauMessagesToRialtoParachain {
 		millau_runtime::Runtime,
 		millau_runtime::WithRialtoParachainMessagesInstance,
 	>;
+
+	type SourceBatchCallBuilder = ();
+	type TargetBatchCallBuilder = ();
 }

relays/bin-substrate/src/chains/rialto_messages_to_millau.rs

@@ -41,4 +41,7 @@ impl SubstrateMessageLane for RialtoMessagesToMillau {
 		rialto_runtime::Runtime,
 		rialto_runtime::WithMillauMessagesInstance,
 	>;
+
+	type SourceBatchCallBuilder = ();
+	type TargetBatchCallBuilder = ();
 }

relays/bin-substrate/src/chains/rialto_parachain_messages_to_millau.rs

@@ -41,4 +41,7 @@ impl SubstrateMessageLane for RialtoParachainMessagesToMillau {
 		rialto_parachain_runtime::Runtime,
 		rialto_parachain_runtime::WithMillauMessagesInstance,
 	>;
+
+	type SourceBatchCallBuilder = ();
+	type TargetBatchCallBuilder = ();
 }

relays/bin-substrate/src/cli/relay_headers_and_messages/mod.rs

@@ -59,7 +59,7 @@ use crate::{
 	declare_chain_cli_schema,
 };
 use bp_messages::LaneId;
-use bp_runtime::{BalanceOf, BlockNumberOf};
+use bp_runtime::BalanceOf;
 use relay_substrate_client::{
 	AccountIdOf, AccountKeyPairOf, Chain, ChainWithBalances, ChainWithTransactions, Client,
 };

relays/lib-substrate-relay/src/messages_lane.rs

@@ -62,15 +62,6 @@ pub trait SubstrateMessageLane: 'static + Clone + Debug + Send + Sync {
 	type TargetBatchCallBuilder: BatchCallBuilder<Self::TargetChain>;
 }
 
-/// Batch call builder.
-pub trait BatchCallBuilder<C: Chain> {
-	/// If `true`, then batch calls are supported at the chain.
-	const BATCH_CALL_SUPPORTED: bool;
-
-	/// Create batch call from given calls vector.
-	fn build_batch_call(calls: Vec<CallOf<C>>) -> CallOf<C>;
-}
-
 /// Adapter that allows all `SubstrateMessageLane` to act as `MessageLane`.
 #[derive(Clone, Debug)]
 pub struct MessageLaneAdapter<P: SubstrateMessageLane> {
@@ -210,6 +201,27 @@ where
 	.map_err(Into::into)
 }
 
+/// Batch call builder.
+pub trait BatchCallBuilder<C: Chain> {
+	/// If `true`, then batch calls are supported at the chain.
+	const BATCH_CALL_SUPPORTED: bool;
+
+	/// Create batch call from given calls vector.
+	fn build_batch_call(_calls: Vec<CallOf<C>>) -> CallOf<C>;
+}
+
+impl<C: Chain> BatchCallBuilder<C> for () {
+	const BATCH_CALL_SUPPORTED: bool = false;
+
+	fn build_batch_call(calls: Vec<CallOf<C>>) -> CallOf<C> {
+		unreachable!(
+			"only called if `BATCH_CALL_SUPPORTED` is true;\
+			`BATCH_CALL_SUPPORTED` is false;\
+			qed"
+		)
+	}
+}
+
 /// Different ways of building `receive_messages_proof` calls.
 pub trait ReceiveMessagesProofCallBuilder<P: SubstrateMessageLane> {
 	/// Given messages proof, build call of `receive_messages_proof` function of bridge