Move some associated types from relay_substrate_client::Chain to bp_runtime::Chain (#1087)

* move some associated types from relay_substrate_client::Chain to bp_runtime::Chain

* dummy commit

* Revert "dummy commit"

This reverts commit 81bc64aa092df115a7c68e7bb7ca5e83ec31fd20.

bridges/bin/millau/runtime/src/lib.rs

@@ -89,7 +89,7 @@ pub type AccountIndex = u32;
 pub type Balance = bp_millau::Balance;
 
 /// Index of a transaction in the chain.
-pub type Index = u32;
+pub type Index = bp_millau::Index;
 
 /// A hash of some data used by the chain.
 pub type Hash = bp_millau::Hash;

bridges/bin/rialto/runtime/src/lib.rs

@@ -95,7 +95,7 @@ pub type AccountIndex = u32;
 pub type Balance = bp_rialto::Balance;
 
 /// Index of a transaction in the chain.
-pub type Index = u32;
+pub type Index = bp_rialto::Index;
 
 /// A hash of some data used by the chain.
 pub type Hash = bp_rialto::Hash;

bridges/modules/grandpa/src/mock.rs

@@ -22,7 +22,7 @@ use frame_support::{construct_runtime, parameter_types, weights::Weight};
 use sp_runtime::{
 	testing::{Header, H256},
 	traits::{BlakeTwo256, IdentityLookup},
-	Perbill,
+	AnySignature, Perbill,
 };
 
 pub type AccountId = u64;
@@ -101,6 +101,11 @@ impl Chain for TestBridgedChain {
 	type Hash = <TestRuntime as frame_system::Config>::Hash;
 	type Hasher = <TestRuntime as frame_system::Config>::Hashing;
 	type Header = <TestRuntime as frame_system::Config>::Header;
+
+	type AccountId = AccountId;
+	type Balance = u64;
+	type Index = u64;
+	type Signature = AnySignature;
 }
 
 pub fn run_test<T>(test: impl FnOnce() -> T) -> T {

bridges/modules/token-swap/src/lib.rs

@@ -122,25 +122,30 @@ pub mod pallet {
 		/// Converter from raw hash (derived from swap) to This chain account.
 		type FromSwapToThisAccountIdConverter: Convert<H256, Self::AccountId>;
 
-		/// Tokens balance type at the Bridged chain.
-		type BridgedBalance: Parameter;
-		/// Account identifier type at the Bridged chain.
-		type BridgedAccountId: Parameter;
-		/// Account public key type at the Bridged chain.
-		type BridgedAccountPublic: Parameter;
-		/// Account signature type at the Bridged chain.
-		type BridgedAccountSignature: Parameter;
+		/// The chain we're bridged to.
+		type BridgedChain: bp_runtime::Chain;
 		/// Converter from raw hash (derived from Bridged chain account) to This chain account.
 		type FromBridgedToThisAccountIdConverter: Convert<H256, Self::AccountId>;
 	}
 
+	/// Type of the Bridged chain.
+	pub type BridgedChainOf<T, I> = <T as Config<I>>::BridgedChain;
+	/// Tokens balance type at the Bridged chain.
+	pub type BridgedBalanceOf<T, I> = bp_runtime::BalanceOf<BridgedChainOf<T, I>>;
+	/// Account identifier type at the Bridged chain.
+	pub type BridgedAccountIdOf<T, I> = bp_runtime::AccountIdOf<BridgedChainOf<T, I>>;
+	/// Account public key type at the Bridged chain.
+	pub type BridgedAccountPublicOf<T, I> = bp_runtime::AccountPublicOf<BridgedChainOf<T, I>>;
+	/// Account signature type at the Bridged chain.
+	pub type BridgedAccountSignatureOf<T, I> = bp_runtime::SignatureOf<BridgedChainOf<T, I>>;
+
 	/// SCALE-encoded `Currency::transfer` call on the bridged chain.
 	pub type RawBridgedTransferCall = Vec<u8>;
 	/// Bridge message payload used by the pallet.
 	pub type MessagePayloadOf<T, I> = bp_message_dispatch::MessagePayload<
 		<T as frame_system::Config>::AccountId,
-		<T as Config<I>>::BridgedAccountPublic,
-		<T as Config<I>>::BridgedAccountSignature,
+		BridgedAccountPublicOf<T, I>,
+		BridgedAccountSignatureOf<T, I>,
 		RawBridgedTransferCall,
 	>;
 	/// Type of `TokenSwap` used by the pallet.
@@ -148,8 +153,8 @@ pub mod pallet {
 		BlockNumberFor<T>,
 		<<T as Config<I>>::ThisCurrency as Currency<<T as frame_system::Config>::AccountId>>::Balance,
 		<T as frame_system::Config>::AccountId,
-		<T as Config<I>>::BridgedBalance,
-		<T as Config<I>>::BridgedAccountId,
+		BridgedBalanceOf<T, I>,
+		BridgedAccountIdOf<T, I>,
 	>;
 
 	#[pallet::pallet]
@@ -160,7 +165,10 @@ pub mod pallet {
 	impl<T: Config<I>, I: 'static> Hooks<BlockNumberFor<T>> for Pallet<T, I> {}
 
 	#[pallet::call]
-	impl<T: Config<I>, I: 'static> Pallet<T, I> {
+	impl<T: Config<I>, I: 'static> Pallet<T, I>
+	where
+		BridgedAccountPublicOf<T, I>: Parameter,
+	{
 		/// Start token swap procedure.
 		///
 		/// The dispatch origin for this call must be exactly the `swap.source_account_at_this_chain` account.
@@ -194,11 +202,11 @@ pub mod pallet {
 		pub fn create_swap(
 			origin: OriginFor<T>,
 			swap: TokenSwapOf<T, I>,
-			target_public_at_bridged_chain: T::BridgedAccountPublic,
+			target_public_at_bridged_chain: BridgedAccountPublicOf<T, I>,
 			bridged_chain_spec_version: u32,
 			bridged_currency_transfer: RawBridgedTransferCall,
 			bridged_currency_transfer_weight: Weight,
-			bridged_currency_transfer_signature: T::BridgedAccountSignature,
+			bridged_currency_transfer_signature: BridgedAccountSignatureOf<T, I>,
 		) -> DispatchResultWithPostInfo {
 			// ensure that the `origin` is the same account that is mentioned in the `swap` intention
 			let origin_account = ensure_signed(origin)?;
@@ -541,12 +549,18 @@ mod tests {
 	const CAN_START_BLOCK_NUMBER: u64 = 10;
 	const CAN_CLAIM_BLOCK_NUMBER: u64 = CAN_START_BLOCK_NUMBER + 1;
 
-	const BRIDGED_CHAIN_ACCOUNT_PUBLIC: BridgedAccountPublic = 1;
-	const BRIDGED_CHAIN_ACCOUNT_SIGNATURE: BridgedAccountSignature = 2;
 	const BRIDGED_CHAIN_ACCOUNT: BridgedAccountId = 3;
 	const BRIDGED_CHAIN_SPEC_VERSION: u32 = 4;
 	const BRIDGED_CHAIN_CALL_WEIGHT: Balance = 5;
 
+	fn bridged_chain_account_public() -> BridgedAccountPublic {
+		1.into()
+	}
+
+	fn bridged_chain_account_signature() -> BridgedAccountSignature {
+		sp_runtime::testing::TestSignature(2, Vec::new())
+	}
+
 	fn test_swap() -> TokenSwapOf<TestRuntime, ()> {
 		bp_token_swap::TokenSwap {
 			swap_type: TokenSwapType::LockClaimUntilBlock(CAN_START_BLOCK_NUMBER, 0.into()),
@@ -569,11 +583,11 @@ mod tests {
 		assert_ok!(Pallet::<TestRuntime>::create_swap(
 			Origin::signed(THIS_CHAIN_ACCOUNT),
 			test_swap(),
-			BRIDGED_CHAIN_ACCOUNT_PUBLIC,
+			bridged_chain_account_public(),
 			BRIDGED_CHAIN_SPEC_VERSION,
 			test_transfer(),
 			BRIDGED_CHAIN_CALL_WEIGHT,
-			BRIDGED_CHAIN_ACCOUNT_SIGNATURE,
+			bridged_chain_account_signature(),
 		));
 	}
 
@@ -591,11 +605,11 @@ mod tests {
 				Pallet::<TestRuntime>::create_swap(
 					Origin::signed(THIS_CHAIN_ACCOUNT + 1),
 					test_swap(),
-					BRIDGED_CHAIN_ACCOUNT_PUBLIC,
+					bridged_chain_account_public(),
 					BRIDGED_CHAIN_SPEC_VERSION,
 					test_transfer(),
 					BRIDGED_CHAIN_CALL_WEIGHT,
-					BRIDGED_CHAIN_ACCOUNT_SIGNATURE,
+					bridged_chain_account_signature(),
 				),
 				Error::<TestRuntime, ()>::MismatchedSwapSourceOrigin
 			);
@@ -611,11 +625,11 @@ mod tests {
 				Pallet::<TestRuntime>::create_swap(
 					Origin::signed(THIS_CHAIN_ACCOUNT),
 					swap,
-					BRIDGED_CHAIN_ACCOUNT_PUBLIC,
+					bridged_chain_account_public(),
 					BRIDGED_CHAIN_SPEC_VERSION,
 					test_transfer(),
 					BRIDGED_CHAIN_CALL_WEIGHT,
-					BRIDGED_CHAIN_ACCOUNT_SIGNATURE,
+					bridged_chain_account_signature(),
 				),
 				Error::<TestRuntime, ()>::TooLowBalanceOnThisChain
 			);
@@ -631,11 +645,11 @@ mod tests {
 				Pallet::<TestRuntime>::create_swap(
 					Origin::signed(THIS_CHAIN_ACCOUNT),
 					swap,
-					BRIDGED_CHAIN_ACCOUNT_PUBLIC,
+					bridged_chain_account_public(),
 					BRIDGED_CHAIN_SPEC_VERSION,
 					test_transfer(),
 					BRIDGED_CHAIN_CALL_WEIGHT,
-					BRIDGED_CHAIN_ACCOUNT_SIGNATURE,
+					bridged_chain_account_signature(),
 				),
 				Error::<TestRuntime, ()>::FailedToTransferToSwapAccount
 			);
@@ -651,11 +665,11 @@ mod tests {
 				Pallet::<TestRuntime>::create_swap(
 					Origin::signed(THIS_CHAIN_ACCOUNT),
 					test_swap(),
-					BRIDGED_CHAIN_ACCOUNT_PUBLIC,
+					bridged_chain_account_public(),
 					BRIDGED_CHAIN_SPEC_VERSION,
 					transfer,
 					BRIDGED_CHAIN_CALL_WEIGHT,
-					BRIDGED_CHAIN_ACCOUNT_SIGNATURE,
+					bridged_chain_account_signature(),
 				),
 				Error::<TestRuntime, ()>::FailedToSendTransferMessage
 			);
@@ -668,22 +682,22 @@ mod tests {
 			assert_ok!(Pallet::<TestRuntime>::create_swap(
 				Origin::signed(THIS_CHAIN_ACCOUNT),
 				test_swap(),
-				BRIDGED_CHAIN_ACCOUNT_PUBLIC,
+				bridged_chain_account_public(),
 				BRIDGED_CHAIN_SPEC_VERSION,
 				test_transfer(),
 				BRIDGED_CHAIN_CALL_WEIGHT,
-				BRIDGED_CHAIN_ACCOUNT_SIGNATURE,
+				bridged_chain_account_signature(),
 			));
 
 			assert_noop!(
 				Pallet::<TestRuntime>::create_swap(
 					Origin::signed(THIS_CHAIN_ACCOUNT),
 					test_swap(),
-					BRIDGED_CHAIN_ACCOUNT_PUBLIC,
+					bridged_chain_account_public(),
 					BRIDGED_CHAIN_SPEC_VERSION,
 					test_transfer(),
 					BRIDGED_CHAIN_CALL_WEIGHT,
-					BRIDGED_CHAIN_ACCOUNT_SIGNATURE,
+					bridged_chain_account_signature(),
 				),
 				Error::<TestRuntime, ()>::SwapAlreadyStarted
 			);
@@ -698,11 +712,11 @@ mod tests {
 				Pallet::<TestRuntime>::create_swap(
 					Origin::signed(THIS_CHAIN_ACCOUNT),
 					test_swap(),
-					BRIDGED_CHAIN_ACCOUNT_PUBLIC,
+					bridged_chain_account_public(),
 					BRIDGED_CHAIN_SPEC_VERSION,
 					test_transfer(),
 					BRIDGED_CHAIN_CALL_WEIGHT,
-					BRIDGED_CHAIN_ACCOUNT_SIGNATURE,
+					bridged_chain_account_signature(),
 				),
 				Error::<TestRuntime, ()>::SwapPeriodIsFinished
 			);
@@ -716,11 +730,11 @@ mod tests {
 			assert_ok!(Pallet::<TestRuntime>::create_swap(
 				Origin::signed(THIS_CHAIN_ACCOUNT),
 				test_swap(),
-				BRIDGED_CHAIN_ACCOUNT_PUBLIC,
+				bridged_chain_account_public(),
 				BRIDGED_CHAIN_SPEC_VERSION,
 				test_transfer(),
 				BRIDGED_CHAIN_CALL_WEIGHT,
-				BRIDGED_CHAIN_ACCOUNT_SIGNATURE,
+				bridged_chain_account_signature(),
 			));
 		});
 	}
@@ -734,11 +748,11 @@ mod tests {
 			assert_ok!(Pallet::<TestRuntime>::create_swap(
 				Origin::signed(THIS_CHAIN_ACCOUNT),
 				test_swap(),
-				BRIDGED_CHAIN_ACCOUNT_PUBLIC,
+				bridged_chain_account_public(),
 				BRIDGED_CHAIN_SPEC_VERSION,
 				test_transfer(),
 				BRIDGED_CHAIN_CALL_WEIGHT,
-				BRIDGED_CHAIN_ACCOUNT_SIGNATURE,
+				bridged_chain_account_signature(),
 			));
 
 			let swap_hash = test_swap_hash();

bridges/modules/token-swap/src/mock.rs

@@ -31,8 +31,8 @@ pub type AccountId = u64;
 pub type Balance = u64;
 pub type Block = frame_system::mocking::MockBlock<TestRuntime>;
 pub type BridgedAccountId = u64;
-pub type BridgedAccountPublic = u64;
-pub type BridgedAccountSignature = u64;
+pub type BridgedAccountPublic = sp_runtime::testing::UintAuthorityId;
+pub type BridgedAccountSignature = sp_runtime::testing::TestSignature;
 pub type BridgedBalance = u64;
 pub type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<TestRuntime>;
 
@@ -122,13 +122,24 @@ impl pallet_bridge_token_swap::Config for TestRuntime {
 	type ThisCurrency = pallet_balances::Pallet<TestRuntime>;
 	type FromSwapToThisAccountIdConverter = TestAccountConverter;
 
-	type BridgedBalance = BridgedBalance;
-	type BridgedAccountId = BridgedAccountId;
-	type BridgedAccountPublic = BridgedAccountPublic;
-	type BridgedAccountSignature = BridgedAccountSignature;
+	type BridgedChain = BridgedChain;
 	type FromBridgedToThisAccountIdConverter = TestAccountConverter;
 }
 
+pub struct BridgedChain;
+
+impl bp_runtime::Chain for BridgedChain {
+	type BlockNumber = u64;
+	type Hash = H256;
+	type Hasher = BlakeTwo256;
+	type Header = sp_runtime::generic::Header<u64, BlakeTwo256>;
+
+	type AccountId = BridgedAccountId;
+	type Balance = BridgedBalance;
+	type Index = u64;
+	type Signature = BridgedAccountSignature;
+}
+
 pub struct TestMessagesBridge;
 
 impl MessagesBridge<AccountId, Balance, MessagePayloadOf<TestRuntime, ()>> for TestMessagesBridge {

bridges/primitives/chain-millau/src/lib.rs

@@ -149,6 +149,9 @@ pub type AccountSigner = MultiSigner;
 /// Balance of an account.
 pub type Balance = u64;
 
+/// Index of a transaction in the chain.
+pub type Index = u32;
+
 /// Weight-to-Fee type used by Millau.
 pub type WeightToFee = IdentityFee<Balance>;
 
@@ -161,6 +164,11 @@ impl Chain for Millau {
 	type Hash = Hash;
 	type Hasher = Hasher;
 	type Header = Header;
+
+	type AccountId = AccountId;
+	type Balance = Balance;
+	type Index = Index;
+	type Signature = Signature;
 }
 
 /// Millau Hasher (Blake2-256 ++ Keccak-256) implementation.

bridges/primitives/chain-rialto/src/lib.rs

@@ -148,6 +148,9 @@ pub type Balance = u128;
 /// An instant or duration in time.
 pub type Moment = u64;
 
+/// Index of a transaction in the chain.
+pub type Index = u32;
+
 /// Weight-to-Fee type used by Rialto.
 pub type WeightToFee = IdentityFee<Balance>;
 
@@ -160,6 +163,11 @@ impl Chain for Rialto {
 	type Hash = Hash;
 	type Hasher = Hasher;
 	type Header = Header;
+
+	type AccountId = AccountId;
+	type Balance = Balance;
+	type Index = Index;
+	type Signature = Signature;
 }
 
 /// Convert a 256-bit hash into an AccountId.

bridges/primitives/polkadot-core/src/lib.rs

@@ -342,6 +342,11 @@ impl Chain for PolkadotLike {
 	type Hash = Hash;
 	type Hasher = Hasher;
 	type Header = Header;
+
+	type AccountId = AccountId;
+	type Balance = Balance;
+	type Index = Index;
+	type Signature = Signature;
 }
 
 /// Convert a 256-bit hash into an AccountId.

bridges/primitives/runtime/src/chain.rs

@@ -15,12 +15,15 @@
 // along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
 
 use frame_support::Parameter;
-use num_traits::AsPrimitive;
-use sp_runtime::traits::{
-	AtLeast32BitUnsigned, Hash as HashT, Header as HeaderT, MaybeDisplay, MaybeMallocSizeOf, MaybeSerializeDeserialize,
-	Member, SimpleBitOps,
+use num_traits::{AsPrimitive, Bounded, CheckedSub, SaturatingAdd, Zero};
+use sp_runtime::{
+	traits::{
+		AtLeast32Bit, AtLeast32BitUnsigned, Hash as HashT, Header as HeaderT, MaybeDisplay, MaybeMallocSizeOf,
+		MaybeSerialize, MaybeSerializeDeserialize, Member, SimpleBitOps, Verify,
+	},
+	FixedPointOperand,
 };
-use sp_std::str::FromStr;
+use sp_std::{convert::TryFrom, fmt::Debug, hash::Hash, str::FromStr};
 
 /// Minimal Substrate-based chain representation that may be used from no_std environment.
 pub trait Chain: Send + Sync + 'static {
@@ -34,7 +37,7 @@ pub trait Chain: Send + Sync + 'static {
 	type BlockNumber: Parameter
 		+ Member
 		+ MaybeSerializeDeserialize
-		+ sp_std::hash::Hash
+		+ Hash
 		+ Copy
 		+ Default
 		+ MaybeDisplay
@@ -54,7 +57,7 @@ pub trait Chain: Send + Sync + 'static {
 	type Hash: Parameter
 		+ Member
 		+ MaybeSerializeDeserialize
-		+ sp_std::hash::Hash
+		+ Hash
 		+ Ord
 		+ Copy
 		+ MaybeDisplay
@@ -75,6 +78,39 @@ pub trait Chain: Send + Sync + 'static {
 	// See here for more info:
 	// https://crates.parity.io/sp_runtime/traits/trait.Header.html
 	type Header: Parameter + HeaderT<Number = Self::BlockNumber, Hash = Self::Hash> + MaybeSerializeDeserialize;
+
+	/// The user account identifier type for the runtime.
+	type AccountId: Parameter + Member + MaybeSerializeDeserialize + Debug + MaybeDisplay + Ord + Default;
+	/// Balance of an account in native tokens.
+	///
+	/// The chain may support multiple tokens, but this particular type is for token that is used
+	/// to pay for transaction dispatch, to reward different relayers (headers, messages), etc.
+	type Balance: AtLeast32BitUnsigned
+		+ FixedPointOperand
+		+ Parameter
+		+ Parameter
+		+ Member
+		+ MaybeSerializeDeserialize
+		+ Clone
+		+ Copy
+		+ Bounded
+		+ CheckedSub
+		+ PartialOrd
+		+ SaturatingAdd
+		+ Zero
+		+ TryFrom<sp_core::U256>;
+	/// Index of a transaction used by the chain.
+	type Index: Parameter
+		+ Member
+		+ MaybeSerialize
+		+ Debug
+		+ Default
+		+ MaybeDisplay
+		+ MaybeSerializeDeserialize
+		+ AtLeast32Bit
+		+ Copy;
+	/// Signature type, used on this chain.
+	type Signature: Parameter + Verify;
 }
 
 /// Block number used by the chain.
@@ -89,5 +125,20 @@ pub type HasherOf<C> = <C as Chain>::Hasher;
 /// Header type used by the chain.
 pub type HeaderOf<C> = <C as Chain>::Header;
 
+/// Account id type used by the chain.
+pub type AccountIdOf<C> = <C as Chain>::AccountId;
+
+/// Balance type used by the chain.
+pub type BalanceOf<C> = <C as Chain>::Balance;
+
+/// Transaction index type used by the chain.
+pub type IndexOf<C> = <C as Chain>::Index;
+
+/// Signature type used by the chain.
+pub type SignatureOf<C> = <C as Chain>::Signature;
+
+/// Account public type used by the chain.
+pub type AccountPublicOf<C> = <SignatureOf<C> as Verify>::Signer;
+
 /// Transaction era used by the chain.
 pub type TransactionEraOf<C> = crate::TransactionEra<BlockNumberOf<C>, HashOf<C>>;

bridges/primitives/runtime/src/lib.rs

@@ -24,7 +24,10 @@ use sp_core::hash::H256;
 use sp_io::hashing::blake2_256;
 use sp_std::convert::TryFrom;
 
-pub use chain::{BlockNumberOf, Chain, HashOf, HasherOf, HeaderOf, TransactionEraOf};
+pub use chain::{
+	AccountIdOf, AccountPublicOf, BalanceOf, BlockNumberOf, Chain, HashOf, HasherOf, HeaderOf, IndexOf, SignatureOf,
+	TransactionEraOf,
+};
 pub use storage_proof::{Error as StorageProofError, StorageProofChecker};
 
 #[cfg(feature = "std")]

bridges/relays/bin-substrate/src/chains/millau_headers_to_rialto.rs

@@ -22,7 +22,7 @@ use sp_core::{Bytes, Pair};
 use bp_header_chain::justification::GrandpaJustification;
 use relay_millau_client::{Millau, SyncHeader as MillauSyncHeader};
 use relay_rialto_client::{Rialto, SigningParams as RialtoSigningParams};
-use relay_substrate_client::{Chain, Client, TransactionSignScheme, UnsignedTransaction};
+use relay_substrate_client::{Client, IndexOf, TransactionSignScheme, UnsignedTransaction};
 use substrate_relay_helper::finality_pipeline::{SubstrateFinalitySyncPipeline, SubstrateFinalityToSubstrate};
 
 /// Millau-to-Rialto finality sync pipeline.
@@ -55,7 +55,7 @@ impl SubstrateFinalitySyncPipeline for MillauFinalityToRialto {
 	fn make_submit_finality_proof_transaction(
 		&self,
 		era: bp_runtime::TransactionEraOf<Rialto>,
-		transaction_nonce: <Rialto as Chain>::Index,
+		transaction_nonce: IndexOf<Rialto>,
 		header: MillauSyncHeader,
 		proof: GrandpaJustification<bp_millau::Header>,
 	) -> Bytes {

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

@@ -28,7 +28,7 @@ use frame_support::weights::Weight;
 use messages_relay::message_lane::MessageLane;
 use relay_millau_client::{HeaderId as MillauHeaderId, Millau, SigningParams as MillauSigningParams};
 use relay_rialto_client::{HeaderId as RialtoHeaderId, Rialto, SigningParams as RialtoSigningParams};
-use relay_substrate_client::{Chain, Client, TransactionSignScheme, UnsignedTransaction};
+use relay_substrate_client::{Chain, Client, IndexOf, TransactionSignScheme, UnsignedTransaction};
 use relay_utils::metrics::MetricsParams;
 use substrate_relay_helper::messages_lane::{
 	select_delivery_transaction_limits, MessagesRelayParams, StandaloneMessagesMetrics, SubstrateMessageLane,
@@ -76,7 +76,7 @@ impl SubstrateMessageLane for MillauMessagesToRialto {
 
 	fn make_messages_receiving_proof_transaction(
 		&self,
-		transaction_nonce: <Millau as Chain>::Index,
+		transaction_nonce: IndexOf<Millau>,
 		_generated_at_block: RialtoHeaderId,
 		proof: <Self::MessageLane as MessageLane>::MessagesReceivingProof,
 	) -> Bytes {
@@ -108,7 +108,7 @@ impl SubstrateMessageLane for MillauMessagesToRialto {
 
 	fn make_messages_delivery_transaction(
 		&self,
-		transaction_nonce: <Rialto as Chain>::Index,
+		transaction_nonce: IndexOf<Rialto>,
 		_generated_at_header: MillauHeaderId,
 		_nonces: RangeInclusive<MessageNonce>,
 		proof: <Self::MessageLane as MessageLane>::MessagesProof,

bridges/relays/bin-substrate/src/chains/rialto_headers_to_millau.rs

@@ -22,7 +22,7 @@ use sp_core::{Bytes, Pair};
 use bp_header_chain::justification::GrandpaJustification;
 use relay_millau_client::{Millau, SigningParams as MillauSigningParams};
 use relay_rialto_client::{Rialto, SyncHeader as RialtoSyncHeader};
-use relay_substrate_client::{Chain, Client, TransactionSignScheme, UnsignedTransaction};
+use relay_substrate_client::{Client, IndexOf, TransactionSignScheme, UnsignedTransaction};
 use substrate_relay_helper::finality_pipeline::{SubstrateFinalitySyncPipeline, SubstrateFinalityToSubstrate};
 
 /// Rialto-to-Millau finality sync pipeline.
@@ -56,7 +56,7 @@ impl SubstrateFinalitySyncPipeline for RialtoFinalityToMillau {
 	fn make_submit_finality_proof_transaction(
 		&self,
 		era: bp_runtime::TransactionEraOf<Millau>,
-		transaction_nonce: <Millau as Chain>::Index,
+		transaction_nonce: IndexOf<Millau>,
 		header: RialtoSyncHeader,
 		proof: GrandpaJustification<bp_rialto::Header>,
 	) -> Bytes {

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

@@ -28,7 +28,7 @@ use frame_support::weights::Weight;
 use messages_relay::message_lane::MessageLane;
 use relay_millau_client::{HeaderId as MillauHeaderId, Millau, SigningParams as MillauSigningParams};
 use relay_rialto_client::{HeaderId as RialtoHeaderId, Rialto, SigningParams as RialtoSigningParams};
-use relay_substrate_client::{Chain, Client, TransactionSignScheme, UnsignedTransaction};
+use relay_substrate_client::{Chain, Client, IndexOf, TransactionSignScheme, UnsignedTransaction};
 use relay_utils::metrics::MetricsParams;
 use substrate_relay_helper::messages_lane::{
 	select_delivery_transaction_limits, MessagesRelayParams, StandaloneMessagesMetrics, SubstrateMessageLane,
@@ -76,7 +76,7 @@ impl SubstrateMessageLane for RialtoMessagesToMillau {
 
 	fn make_messages_receiving_proof_transaction(
 		&self,
-		transaction_nonce: <Rialto as Chain>::Index,
+		transaction_nonce: IndexOf<Rialto>,
 		_generated_at_block: MillauHeaderId,
 		proof: <Self::MessageLane as MessageLane>::MessagesReceivingProof,
 	) -> Bytes {
@@ -108,7 +108,7 @@ impl SubstrateMessageLane for RialtoMessagesToMillau {
 
 	fn make_messages_delivery_transaction(
 		&self,
-		transaction_nonce: <Millau as Chain>::Index,
+		transaction_nonce: IndexOf<Millau>,
 		_generated_at_header: RialtoHeaderId,
 		_nonces: RangeInclusive<MessageNonce>,
 		proof: <Self::MessageLane as MessageLane>::MessagesProof,

bridges/relays/bin-substrate/src/chains/rococo_headers_to_wococo.rs

@@ -21,7 +21,7 @@ use sp_core::{Bytes, Pair};
 
 use bp_header_chain::justification::GrandpaJustification;
 use relay_rococo_client::{Rococo, SyncHeader as RococoSyncHeader};
-use relay_substrate_client::{Chain, Client, TransactionSignScheme, UnsignedTransaction};
+use relay_substrate_client::{Client, IndexOf, TransactionSignScheme, UnsignedTransaction};
 use relay_utils::metrics::MetricsParams;
 use relay_wococo_client::{SigningParams as WococoSigningParams, Wococo};
 use substrate_relay_helper::finality_pipeline::{SubstrateFinalitySyncPipeline, SubstrateFinalityToSubstrate};
@@ -78,7 +78,7 @@ impl SubstrateFinalitySyncPipeline for RococoFinalityToWococo {
 	fn make_submit_finality_proof_transaction(
 		&self,
 		era: bp_runtime::TransactionEraOf<Wococo>,
-		transaction_nonce: <Wococo as Chain>::Index,
+		transaction_nonce: IndexOf<Wococo>,
 		header: RococoSyncHeader,
 		proof: GrandpaJustification<bp_rococo::Header>,
 	) -> Bytes {

bridges/relays/bin-substrate/src/chains/rococo_messages_to_wococo.rs

@@ -26,7 +26,7 @@ use bridge_runtime_common::messages::target::FromBridgedChainMessagesProof;
 use frame_support::weights::Weight;
 use messages_relay::message_lane::MessageLane;
 use relay_rococo_client::{HeaderId as RococoHeaderId, Rococo, SigningParams as RococoSigningParams};
-use relay_substrate_client::{Chain, Client, TransactionSignScheme, UnsignedTransaction};
+use relay_substrate_client::{Chain, Client, IndexOf, TransactionSignScheme, UnsignedTransaction};
 use relay_utils::metrics::MetricsParams;
 use relay_wococo_client::{HeaderId as WococoHeaderId, SigningParams as WococoSigningParams, Wococo};
 use substrate_relay_helper::messages_lane::{
@@ -75,7 +75,7 @@ impl SubstrateMessageLane for RococoMessagesToWococo {
 
 	fn make_messages_receiving_proof_transaction(
 		&self,
-		transaction_nonce: <Rococo as Chain>::Index,
+		transaction_nonce: IndexOf<Rococo>,
 		_generated_at_block: WococoHeaderId,
 		proof: <Self::MessageLane as MessageLane>::MessagesReceivingProof,
 	) -> Bytes {
@@ -109,7 +109,7 @@ impl SubstrateMessageLane for RococoMessagesToWococo {
 
 	fn make_messages_delivery_transaction(
 		&self,
-		transaction_nonce: <Wococo as Chain>::Index,
+		transaction_nonce: IndexOf<Wococo>,
 		_generated_at_header: RococoHeaderId,
 		_nonces: RangeInclusive<MessageNonce>,
 		proof: <Self::MessageLane as MessageLane>::MessagesProof,

bridges/relays/bin-substrate/src/chains/westend_headers_to_millau.rs

@@ -21,7 +21,7 @@ use sp_core::{Bytes, Pair};
 
 use bp_header_chain::justification::GrandpaJustification;
 use relay_millau_client::{Millau, SigningParams as MillauSigningParams};
-use relay_substrate_client::{Chain, Client, TransactionSignScheme, UnsignedTransaction};
+use relay_substrate_client::{Client, IndexOf, TransactionSignScheme, UnsignedTransaction};
 use relay_utils::metrics::MetricsParams;
 use relay_westend_client::{SyncHeader as WestendSyncHeader, Westend};
 use substrate_relay_helper::finality_pipeline::{SubstrateFinalitySyncPipeline, SubstrateFinalityToSubstrate};
@@ -64,7 +64,7 @@ impl SubstrateFinalitySyncPipeline for WestendFinalityToMillau {
 	fn make_submit_finality_proof_transaction(
 		&self,
 		era: bp_runtime::TransactionEraOf<Millau>,
-		transaction_nonce: <Millau as Chain>::Index,
+		transaction_nonce: IndexOf<Millau>,
 		header: WestendSyncHeader,
 		proof: GrandpaJustification<bp_westend::Header>,
 	) -> Bytes {

bridges/relays/bin-substrate/src/chains/wococo_headers_to_rococo.rs

@@ -21,7 +21,7 @@ use sp_core::{Bytes, Pair};
 
 use bp_header_chain::justification::GrandpaJustification;
 use relay_rococo_client::{Rococo, SigningParams as RococoSigningParams};
-use relay_substrate_client::{Chain, Client, TransactionSignScheme, UnsignedTransaction};
+use relay_substrate_client::{Client, IndexOf, TransactionSignScheme, UnsignedTransaction};
 use relay_utils::metrics::MetricsParams;
 use relay_wococo_client::{SyncHeader as WococoSyncHeader, Wococo};
 use substrate_relay_helper::finality_pipeline::{SubstrateFinalitySyncPipeline, SubstrateFinalityToSubstrate};
@@ -83,7 +83,7 @@ impl SubstrateFinalitySyncPipeline for WococoFinalityToRococo {
 	fn make_submit_finality_proof_transaction(
 		&self,
 		era: bp_runtime::TransactionEraOf<Rococo>,
-		transaction_nonce: <Rococo as Chain>::Index,
+		transaction_nonce: IndexOf<Rococo>,
 		header: WococoSyncHeader,
 		proof: GrandpaJustification<bp_wococo::Header>,
 	) -> Bytes {

bridges/relays/bin-substrate/src/chains/wococo_messages_to_rococo.rs

@@ -26,7 +26,7 @@ use bridge_runtime_common::messages::target::FromBridgedChainMessagesProof;
 use frame_support::weights::Weight;
 use messages_relay::message_lane::MessageLane;
 use relay_rococo_client::{HeaderId as RococoHeaderId, Rococo, SigningParams as RococoSigningParams};
-use relay_substrate_client::{Chain, Client, TransactionSignScheme, UnsignedTransaction};
+use relay_substrate_client::{Chain, Client, IndexOf, TransactionSignScheme, UnsignedTransaction};
 use relay_utils::metrics::MetricsParams;
 use relay_wococo_client::{HeaderId as WococoHeaderId, SigningParams as WococoSigningParams, Wococo};
 use substrate_relay_helper::messages_lane::{
@@ -74,7 +74,7 @@ impl SubstrateMessageLane for WococoMessagesToRococo {
 
 	fn make_messages_receiving_proof_transaction(
 		&self,
-		transaction_nonce: <Wococo as Chain>::Index,
+		transaction_nonce: IndexOf<Wococo>,
 		_generated_at_block: RococoHeaderId,
 		proof: <Self::MessageLane as MessageLane>::MessagesReceivingProof,
 	) -> Bytes {
@@ -108,7 +108,7 @@ impl SubstrateMessageLane for WococoMessagesToRococo {
 
 	fn make_messages_delivery_transaction(
 		&self,
-		transaction_nonce: <Rococo as Chain>::Index,
+		transaction_nonce: IndexOf<Rococo>,
 		_generated_at_header: WococoHeaderId,
 		_nonces: RangeInclusive<MessageNonce>,
 		proof: <Self::MessageLane as MessageLane>::MessagesProof,

bridges/relays/bin-substrate/src/cli/estimate_fee.rs

@@ -17,6 +17,7 @@
 use crate::cli::bridge::FullBridge;
 use crate::cli::{Balance, CliChain, HexBytes, HexLaneId, SourceConnectionParams};
 use crate::select_full_bridge;
+use bp_runtime::BalanceOf;
 use codec::{Decode, Encode};
 use relay_substrate_client::Chain;
 use structopt::StructOpt;
@@ -53,7 +54,7 @@ impl EstimateFee {
 			let lane = lane.into();
 			let payload = Source::encode_message(payload).map_err(|e| anyhow::format_err!("{:?}", e))?;
 
-			let fee: <Source as Chain>::Balance =
+			let fee: BalanceOf<Source> =
 				estimate_message_delivery_and_dispatch_fee(&source_client, ESTIMATE_MESSAGE_FEE_METHOD, lane, payload)
 					.await?;
 

bridges/relays/bin-substrate/src/cli/send_message.rs

@@ -22,6 +22,7 @@ use crate::cli::{
 	TargetSigningParams,
 };
 use bp_message_dispatch::{CallOrigin, MessagePayload};
+use bp_runtime::BalanceOf;
 use codec::Encode;
 use frame_support::weights::Weight;
 use relay_substrate_client::{Chain, TransactionSignScheme, UnsignedTransaction};
@@ -159,7 +160,7 @@ impl SendMessage {
 			let fee = match self.fee {
 				Some(fee) => fee,
 				None => Balance(
-					estimate_message_delivery_and_dispatch_fee::<<Source as Chain>::Balance, _, _>(
+					estimate_message_delivery_and_dispatch_fee::<BalanceOf<Source>, _, _>(
 						&source_client,
 						ESTIMATE_MESSAGE_FEE_METHOD,
 						lane,

bridges/relays/client-kusama/src/lib.rs

@@ -31,6 +31,11 @@ impl ChainBase for Kusama {
 	type Hash = bp_kusama::Hash;
 	type Hasher = bp_kusama::Hasher;
 	type Header = bp_kusama::Header;
+
+	type AccountId = bp_kusama::AccountId;
+	type Balance = bp_kusama::Balance;
+	type Index = bp_kusama::Nonce;
+	type Signature = bp_kusama::Signature;
 }
 
 impl Chain for Kusama {
@@ -39,11 +44,8 @@ impl Chain for Kusama {
 	const STORAGE_PROOF_OVERHEAD: u32 = bp_kusama::EXTRA_STORAGE_PROOF_SIZE;
 	const MAXIMAL_ENCODED_ACCOUNT_ID_SIZE: u32 = bp_kusama::MAXIMAL_ENCODED_ACCOUNT_ID_SIZE;
 
-	type AccountId = bp_kusama::AccountId;
-	type Index = bp_kusama::Nonce;
 	type SignedBlock = bp_kusama::SignedBlock;
 	type Call = ();
-	type Balance = bp_kusama::Balance;
 	type WeightToFee = bp_kusama::WeightToFee;
 }
 

bridges/relays/client-millau/src/lib.rs

@@ -18,7 +18,8 @@
 
 use codec::{Compact, Decode, Encode};
 use relay_substrate_client::{
-	Chain, ChainBase, ChainWithBalances, TransactionEraOf, TransactionSignScheme, UnsignedTransaction,
+	BalanceOf, Chain, ChainBase, ChainWithBalances, IndexOf, TransactionEraOf, TransactionSignScheme,
+	UnsignedTransaction,
 };
 use sp_core::{storage::StorageKey, Pair};
 use sp_runtime::{generic::SignedPayload, traits::IdentifyAccount};
@@ -36,6 +37,11 @@ impl ChainBase for Millau {
 	type Hash = millau_runtime::Hash;
 	type Hasher = millau_runtime::Hashing;
 	type Header = millau_runtime::Header;
+
+	type AccountId = millau_runtime::AccountId;
+	type Balance = millau_runtime::Balance;
+	type Index = millau_runtime::Index;
+	type Signature = millau_runtime::Signature;
 }
 
 impl Chain for Millau {
@@ -44,11 +50,8 @@ impl Chain for Millau {
 	const STORAGE_PROOF_OVERHEAD: u32 = bp_millau::EXTRA_STORAGE_PROOF_SIZE;
 	const MAXIMAL_ENCODED_ACCOUNT_ID_SIZE: u32 = bp_millau::MAXIMAL_ENCODED_ACCOUNT_ID_SIZE;
 
-	type AccountId = millau_runtime::AccountId;
-	type Index = millau_runtime::Index;
 	type SignedBlock = millau_runtime::SignedBlock;
 	type Call = millau_runtime::Call;
-	type Balance = millau_runtime::Balance;
 	type WeightToFee = bp_millau::WeightToFee;
 }
 
@@ -115,10 +118,10 @@ impl TransactionSignScheme for Millau {
 		let extra = &tx.signature.as_ref()?.2;
 		Some(UnsignedTransaction {
 			call: tx.function,
-			nonce: Compact::<<Self::Chain as Chain>::Index>::decode(&mut &extra.4.encode()[..])
+			nonce: Compact::<IndexOf<Self::Chain>>::decode(&mut &extra.4.encode()[..])
 				.ok()?
 				.into(),
-			tip: Compact::<<Self::Chain as Chain>::Balance>::decode(&mut &extra.6.encode()[..])
+			tip: Compact::<BalanceOf<Self::Chain>>::decode(&mut &extra.6.encode()[..])
 				.ok()?
 				.into(),
 		})

bridges/relays/client-polkadot/src/lib.rs

@@ -31,6 +31,11 @@ impl ChainBase for Polkadot {
 	type Hash = bp_polkadot::Hash;
 	type Hasher = bp_polkadot::Hasher;
 	type Header = bp_polkadot::Header;
+
+	type AccountId = bp_polkadot::AccountId;
+	type Balance = bp_polkadot::Balance;
+	type Index = bp_polkadot::Nonce;
+	type Signature = bp_polkadot::Signature;
 }
 
 impl Chain for Polkadot {
@@ -39,11 +44,8 @@ impl Chain for Polkadot {
 	const STORAGE_PROOF_OVERHEAD: u32 = bp_polkadot::EXTRA_STORAGE_PROOF_SIZE;
 	const MAXIMAL_ENCODED_ACCOUNT_ID_SIZE: u32 = bp_polkadot::MAXIMAL_ENCODED_ACCOUNT_ID_SIZE;
 
-	type AccountId = bp_polkadot::AccountId;
-	type Index = bp_polkadot::Nonce;
 	type SignedBlock = bp_polkadot::SignedBlock;
 	type Call = ();
-	type Balance = bp_polkadot::Balance;
 	type WeightToFee = bp_polkadot::WeightToFee;
 }
 

bridges/relays/client-rialto/src/lib.rs

@@ -18,7 +18,8 @@
 
 use codec::{Compact, Decode, Encode};
 use relay_substrate_client::{
-	Chain, ChainBase, ChainWithBalances, TransactionEraOf, TransactionSignScheme, UnsignedTransaction,
+	BalanceOf, Chain, ChainBase, ChainWithBalances, IndexOf, TransactionEraOf, TransactionSignScheme,
+	UnsignedTransaction,
 };
 use sp_core::{storage::StorageKey, Pair};
 use sp_runtime::{generic::SignedPayload, traits::IdentifyAccount};
@@ -36,6 +37,11 @@ impl ChainBase for Rialto {
 	type Hash = rialto_runtime::Hash;
 	type Hasher = rialto_runtime::Hashing;
 	type Header = rialto_runtime::Header;
+
+	type AccountId = rialto_runtime::AccountId;
+	type Balance = rialto_runtime::Balance;
+	type Index = rialto_runtime::Index;
+	type Signature = rialto_runtime::Signature;
 }
 
 impl Chain for Rialto {
@@ -44,11 +50,8 @@ impl Chain for Rialto {
 	const STORAGE_PROOF_OVERHEAD: u32 = bp_rialto::EXTRA_STORAGE_PROOF_SIZE;
 	const MAXIMAL_ENCODED_ACCOUNT_ID_SIZE: u32 = bp_rialto::MAXIMAL_ENCODED_ACCOUNT_ID_SIZE;
 
-	type AccountId = rialto_runtime::AccountId;
-	type Index = rialto_runtime::Index;
 	type SignedBlock = rialto_runtime::SignedBlock;
 	type Call = rialto_runtime::Call;
-	type Balance = rialto_runtime::Balance;
 	type WeightToFee = bp_rialto::WeightToFee;
 }
 
@@ -115,10 +118,10 @@ impl TransactionSignScheme for Rialto {
 		let extra = &tx.signature.as_ref()?.2;
 		Some(UnsignedTransaction {
 			call: tx.function,
-			nonce: Compact::<<Self::Chain as Chain>::Index>::decode(&mut &extra.4.encode()[..])
+			nonce: Compact::<IndexOf<Self::Chain>>::decode(&mut &extra.4.encode()[..])
 				.ok()?
 				.into(),
-			tip: Compact::<<Self::Chain as Chain>::Balance>::decode(&mut &extra.6.encode()[..])
+			tip: Compact::<BalanceOf<Self::Chain>>::decode(&mut &extra.6.encode()[..])
 				.ok()?
 				.into(),
 		})

bridges/relays/client-rococo/src/lib.rs

@@ -41,6 +41,11 @@ impl ChainBase for Rococo {
 	type Hash = bp_rococo::Hash;
 	type Hasher = bp_rococo::Hashing;
 	type Header = bp_rococo::Header;
+
+	type AccountId = bp_rococo::AccountId;
+	type Balance = bp_rococo::Balance;
+	type Index = bp_rococo::Nonce;
+	type Signature = bp_rococo::Signature;
 }
 
 impl Chain for Rococo {
@@ -49,11 +54,8 @@ impl Chain for Rococo {
 	const STORAGE_PROOF_OVERHEAD: u32 = bp_rococo::EXTRA_STORAGE_PROOF_SIZE;
 	const MAXIMAL_ENCODED_ACCOUNT_ID_SIZE: u32 = bp_rococo::MAXIMAL_ENCODED_ACCOUNT_ID_SIZE;
 
-	type AccountId = bp_rococo::AccountId;
-	type Index = bp_rococo::Index;
 	type SignedBlock = bp_rococo::SignedBlock;
 	type Call = crate::runtime::Call;
-	type Balance = bp_rococo::Balance;
 	type WeightToFee = bp_rococo::WeightToFee;
 }
 

bridges/relays/client-substrate/src/chain.rs

@@ -16,17 +16,14 @@
 
 use bp_runtime::{Chain as ChainBase, TransactionEraOf};
 use codec::{Codec, Encode};
-use frame_support::{weights::WeightToFeePolynomial, Parameter};
+use frame_support::weights::WeightToFeePolynomial;
 use jsonrpsee_ws_client::{DeserializeOwned, Serialize};
-use num_traits::{Bounded, CheckedSub, SaturatingAdd, Zero};
+use num_traits::Zero;
 use sp_core::{storage::StorageKey, Pair};
 use sp_runtime::{
 	generic::SignedBlock,
-	traits::{
-		AtLeast32Bit, AtLeast32BitUnsigned, Block as BlockT, Dispatchable, MaybeDisplay, MaybeSerialize,
-		MaybeSerializeDeserialize, Member,
-	},
-	EncodedJustification, FixedPointOperand,
+	traits::{Block as BlockT, Dispatchable, Member},
+	EncodedJustification,
 };
 use std::{fmt::Debug, time::Duration};
 
@@ -44,49 +41,15 @@ pub trait Chain: ChainBase + Clone {
 	/// Maximal size (in bytes) of SCALE-encoded account id on this chain.
 	const MAXIMAL_ENCODED_ACCOUNT_ID_SIZE: u32;
 
-	/// The user account identifier type for the runtime.
-	type AccountId: Parameter + Member + MaybeSerializeDeserialize + Debug + MaybeDisplay + Ord + Default;
-	/// Index of a transaction used by the chain.
-	type Index: Parameter
-		+ Member
-		+ MaybeSerialize
-		+ Debug
-		+ Default
-		+ MaybeDisplay
-		+ DeserializeOwned
-		+ AtLeast32Bit
-		+ Copy;
 	/// Block type.
 	type SignedBlock: Member + Serialize + DeserializeOwned + BlockWithJustification<Self::Header>;
 	/// The aggregated `Call` type.
 	type Call: Clone + Dispatchable + Debug;
-	/// Balance of an account in native tokens.
-	///
-	/// The chain may support multiple tokens, but this particular type is for token that is used
-	/// to pay for transaction dispatch, to reward different relayers (headers, messages), etc.
-	type Balance: AtLeast32BitUnsigned
-		+ FixedPointOperand
-		+ Parameter
-		+ Parameter
-		+ Member
-		+ DeserializeOwned
-		+ Clone
-		+ Copy
-		+ Bounded
-		+ CheckedSub
-		+ PartialOrd
-		+ SaturatingAdd
-		+ Zero
-		+ std::convert::TryFrom<sp_core::U256>;
 
 	/// Type that is used by the chain, to convert from weight to fee.
 	type WeightToFee: WeightToFeePolynomial<Balance = Self::Balance>;
 }
 
-/// Balance type used by the chain
-pub type BalanceOf<C> = <C as Chain>::Balance;
-/// Index type used by the chain
-pub type IndexOf<C> = <C as Chain>::Index;
 /// Weight-to-Fee type used by the chain
 pub type WeightToFeeOf<C> = <C as Chain>::WeightToFee;
 

bridges/relays/client-substrate/src/guard.rs

@@ -165,6 +165,7 @@ impl<C: ChainWithBalances> Environment<C> for Client<C> {
 #[cfg(test)]
 mod tests {
 	use super::*;
+	use frame_support::weights::IdentityFee;
 	use futures::{
 		channel::mpsc::{unbounded, UnboundedReceiver, UnboundedSender},
 		future::FutureExt,
@@ -180,6 +181,11 @@ mod tests {
 		type Hash = sp_core::H256;
 		type Hasher = sp_runtime::traits::BlakeTwo256;
 		type Header = sp_runtime::generic::Header<u32, sp_runtime::traits::BlakeTwo256>;
+
+		type AccountId = u32;
+		type Balance = u32;
+		type Index = u32;
+		type Signature = sp_runtime::testing::TestSignature;
 	}
 
 	impl Chain for TestChain {
@@ -188,13 +194,10 @@ mod tests {
 		const STORAGE_PROOF_OVERHEAD: u32 = 0;
 		const MAXIMAL_ENCODED_ACCOUNT_ID_SIZE: u32 = 0;
 
-		type AccountId = u32;
-		type Index = u32;
 		type SignedBlock =
 			sp_runtime::generic::SignedBlock<sp_runtime::generic::Block<Self::Header, sp_runtime::OpaqueExtrinsic>>;
 		type Call = ();
-		type Balance = u32;
-		type WeightToFee = frame_support::weights::IdentityFee<u32>;
+		type WeightToFee = IdentityFee<u32>;
 	}
 
 	impl ChainWithBalances for TestChain {

bridges/relays/client-substrate/src/lib.rs

@@ -32,13 +32,14 @@ pub mod metrics;
 use std::time::Duration;
 
 pub use crate::chain::{
-	BalanceOf, BlockWithJustification, Chain, ChainWithBalances, IndexOf, TransactionSignScheme, UnsignedTransaction,
-	WeightToFeeOf,
+	BlockWithJustification, Chain, ChainWithBalances, TransactionSignScheme, UnsignedTransaction, WeightToFeeOf,
 };
 pub use crate::client::{Client, JustificationsSubscription, OpaqueGrandpaAuthoritiesSet};
 pub use crate::error::{Error, Result};
 pub use crate::sync_header::SyncHeader;
-pub use bp_runtime::{BlockNumberOf, Chain as ChainBase, HashOf, HeaderOf, TransactionEra, TransactionEraOf};
+pub use bp_runtime::{
+	BalanceOf, BlockNumberOf, Chain as ChainBase, HashOf, HeaderOf, IndexOf, TransactionEra, TransactionEraOf,
+};
 
 /// Header id used by the chain.
 pub type HeaderIdOf<C> = relay_utils::HeaderId<HashOf<C>, BlockNumberOf<C>>;

bridges/relays/client-westend/src/lib.rs

@@ -35,6 +35,11 @@ impl ChainBase for Westend {
 	type Hash = bp_westend::Hash;
 	type Hasher = bp_westend::Hasher;
 	type Header = bp_westend::Header;
+
+	type AccountId = bp_westend::AccountId;
+	type Balance = bp_westend::Balance;
+	type Index = bp_westend::Nonce;
+	type Signature = bp_westend::Signature;
 }
 
 impl Chain for Westend {
@@ -43,11 +48,8 @@ impl Chain for Westend {
 	const STORAGE_PROOF_OVERHEAD: u32 = bp_westend::EXTRA_STORAGE_PROOF_SIZE;
 	const MAXIMAL_ENCODED_ACCOUNT_ID_SIZE: u32 = bp_westend::MAXIMAL_ENCODED_ACCOUNT_ID_SIZE;
 
-	type AccountId = bp_westend::AccountId;
-	type Index = bp_westend::Nonce;
 	type SignedBlock = bp_westend::SignedBlock;
 	type Call = bp_westend::Call;
-	type Balance = bp_westend::Balance;
 	type WeightToFee = bp_westend::WeightToFee;
 }
 

bridges/relays/client-wococo/src/lib.rs

@@ -41,6 +41,11 @@ impl ChainBase for Wococo {
 	type Hash = bp_wococo::Hash;
 	type Hasher = bp_wococo::Hashing;
 	type Header = bp_wococo::Header;
+
+	type AccountId = bp_wococo::AccountId;
+	type Balance = bp_wococo::Balance;
+	type Index = bp_wococo::Nonce;
+	type Signature = bp_wococo::Signature;
 }
 
 impl Chain for Wococo {
@@ -49,11 +54,8 @@ impl Chain for Wococo {
 	const STORAGE_PROOF_OVERHEAD: u32 = bp_wococo::EXTRA_STORAGE_PROOF_SIZE;
 	const MAXIMAL_ENCODED_ACCOUNT_ID_SIZE: u32 = bp_wococo::MAXIMAL_ENCODED_ACCOUNT_ID_SIZE;
 
-	type AccountId = bp_wococo::AccountId;
-	type Index = bp_wococo::Index;
 	type SignedBlock = bp_wococo::SignedBlock;
 	type Call = crate::runtime::Call;
-	type Balance = bp_wococo::Balance;
 	type WeightToFee = bp_wococo::WeightToFee;
 }
 

bridges/relays/lib-substrate-relay/src/finality_pipeline.rs

@@ -19,6 +19,7 @@
 use crate::finality_target::SubstrateFinalityTarget;
 
 use bp_header_chain::justification::GrandpaJustification;
+use bp_runtime::AccountIdOf;
 use finality_relay::{FinalitySyncParams, FinalitySyncPipeline};
 use relay_substrate_client::{finality_source::FinalitySource, BlockNumberOf, Chain, Client, HashOf, SyncHeader};
 use relay_utils::{metrics::MetricsParams, BlockNumberBase};
@@ -63,13 +64,13 @@ pub trait SubstrateFinalitySyncPipeline: 'static + Clone + Debug + Send + Sync {
 	fn start_relay_guards(&self) {}
 
 	/// Returns id of account that we're using to sign transactions at target chain.
-	fn transactions_author(&self) -> <Self::TargetChain as Chain>::AccountId;
+	fn transactions_author(&self) -> AccountIdOf<Self::TargetChain>;
 
 	/// Make submit header transaction.
 	fn make_submit_finality_proof_transaction(
 		&self,
 		era: bp_runtime::TransactionEraOf<Self::TargetChain>,
-		transaction_nonce: <Self::TargetChain as Chain>::Index,
+		transaction_nonce: bp_runtime::IndexOf<Self::TargetChain>,
 		header: <Self::FinalitySyncPipeline as FinalitySyncPipeline>::Header,
 		proof: <Self::FinalitySyncPipeline as FinalitySyncPipeline>::FinalityProof,
 	) -> Bytes;

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

@@ -22,6 +22,7 @@ use crate::on_demand_headers::OnDemandHeadersRelay;
 
 use async_trait::async_trait;
 use bp_messages::{LaneId, MessageNonce};
+use bp_runtime::{AccountIdOf, IndexOf};
 use frame_support::weights::Weight;
 use messages_relay::message_lane::{MessageLane, SourceHeaderIdOf, TargetHeaderIdOf};
 use relay_substrate_client::{
@@ -101,24 +102,24 @@ pub trait SubstrateMessageLane: 'static + Clone + Send + Sync {
 	type TargetChain: Chain;
 
 	/// Returns id of account that we're using to sign transactions at target chain (messages proof).
-	fn target_transactions_author(&self) -> <Self::TargetChain as Chain>::AccountId;
+	fn target_transactions_author(&self) -> AccountIdOf<Self::TargetChain>;
 
 	/// Make messages delivery transaction.
 	fn make_messages_delivery_transaction(
 		&self,
-		transaction_nonce: <Self::TargetChain as Chain>::Index,
+		transaction_nonce: IndexOf<Self::TargetChain>,
 		generated_at_header: SourceHeaderIdOf<Self::MessageLane>,
 		nonces: RangeInclusive<MessageNonce>,
 		proof: <Self::MessageLane as MessageLane>::MessagesProof,
 	) -> Bytes;
 
 	/// Returns id of account that we're using to sign transactions at source chain (delivery proof).
-	fn source_transactions_author(&self) -> <Self::SourceChain as Chain>::AccountId;
+	fn source_transactions_author(&self) -> AccountIdOf<Self::SourceChain>;
 
 	/// Make messages receiving proof transaction.
 	fn make_messages_receiving_proof_transaction(
 		&self,
-		transaction_nonce: <Self::SourceChain as Chain>::Index,
+		transaction_nonce: IndexOf<Self::SourceChain>,
 		generated_at_header: TargetHeaderIdOf<Self::MessageLane>,
 		proof: <Self::MessageLane as MessageLane>::MessagesReceivingProof,
 	) -> Bytes;

bridges/relays/lib-substrate-relay/src/messages_target.rs

@@ -108,7 +108,7 @@ where
 		BlockNumber = <P::MessageLane as MessageLane>::SourceHeaderNumber,
 		Balance = <P::MessageLane as MessageLane>::SourceChainBalance,
 	>,
-	BalanceOf<P::SourceChain>: TryFrom<<P::TargetChain as Chain>::Balance> + Bounded,
+	BalanceOf<P::SourceChain>: TryFrom<BalanceOf<P::TargetChain>> + Bounded,
 	P::TargetChain: Chain<
 		Hash = <P::MessageLane as MessageLane>::TargetHeaderHash,
 		BlockNumber = <P::MessageLane as MessageLane>::TargetHeaderNumber,
@@ -454,7 +454,7 @@ mod tests {
 
 		fn make_messages_receiving_proof_transaction(
 			&self,
-			_transaction_nonce: <Rococo as Chain>::Index,
+			_transaction_nonce: IndexOf<Rococo>,
 			_generated_at_block: TargetHeaderIdOf<Self::MessageLane>,
 			_proof: <Self::MessageLane as MessageLane>::MessagesReceivingProof,
 		) -> Bytes {
@@ -467,7 +467,7 @@ mod tests {
 
 		fn make_messages_delivery_transaction(
 			&self,
-			_transaction_nonce: <Wococo as Chain>::Index,
+			_transaction_nonce: IndexOf<Wococo>,
 			_generated_at_header: SourceHeaderIdOf<Self::MessageLane>,
 			_nonces: RangeInclusive<MessageNonce>,
 			_proof: <Self::MessageLane as MessageLane>::MessagesProof,