XCMv4 (#1230)

# Note for reviewer

Most changes are just syntax changes necessary for the new version.
Most important files should be the ones under the `xcm` folder.

# Description 

Added XCMv4.

## Removed `Multi` prefix
The following types have been renamed:
- MultiLocation -> Location
- MultiAsset -> Asset
- MultiAssets -> Assets
- InteriorMultiLocation -> InteriorLocation
- MultiAssetFilter -> AssetFilter
- VersionedMultiAsset -> VersionedAsset
- WildMultiAsset -> WildAsset
- VersionedMultiLocation -> VersionedLocation

In order to fix a name conflict, the `Assets` in `xcm-executor` were
renamed to `HoldingAssets`, as they represent assets in holding.

## Removed `Abstract` asset id

It was not being used anywhere and this simplifies the code.

Now assets are just constructed as follows:

```rust
let asset: Asset = (AssetId(Location::new(1, Here)), 100u128).into();
```

No need for specifying `Concrete` anymore.

## Outcome is now a named fields struct

Instead of

```rust
pub enum Outcome {
  Complete(Weight),
  Incomplete(Weight, Error),
  Error(Error),
}
```

we now have

```rust
pub enum Outcome {
  Complete { used: Weight },
  Incomplete { used: Weight, error: Error },
  Error { error: Error },
}
```

## Added Reanchorable trait

Now both locations and assets implement this trait, making it easier to
reanchor both.

## New syntax for building locations and junctions

Now junctions are built using the following methods:

```rust
let location = Location {
    parents: 1,
    interior: [Parachain(1000), PalletInstance(50), GeneralIndex(1984)].into()
};
```

or

```rust
let location = Location::new(1, [Parachain(1000), PalletInstance(50), GeneralIndex(1984)]);
```

And they are matched like so:

```rust
match location.unpack() {
  (1, [Parachain(id)]) => ...
  (0, Here) => ...,
  (1, [_]) => ...,
}
```

This syntax is mandatory in v4, and has been also implemented for v2 and
v3 for easier migration.

This was needed to make all sizes smaller.

# TODO
- [x] Scaffold v4
- [x] Port github.com/paritytech/polkadot/pull/7236
- [x] Remove `Multi` prefix
- [x] Remove `Abstract` asset id

---------

Co-authored-by: command-bot <>
Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-westend/src/bridge_to_rococo_config.rs

@@ -47,7 +47,7 @@ use frame_support::{
 use sp_runtime::RuntimeDebug;
 use xcm::{
 	latest::prelude::*,
-	prelude::{InteriorMultiLocation, NetworkId},
+	prelude::{InteriorLocation, NetworkId},
 };
 use xcm_builder::BridgeBlobDispatcher;
 
@@ -63,12 +63,12 @@ parameter_types! {
 	pub const MaxUnconfirmedMessagesAtInboundLane: bp_messages::MessageNonce =
 		bp_bridge_hub_westend::MAX_UNCONFIRMED_MESSAGES_IN_CONFIRMATION_TX;
 	pub const BridgeHubRococoChainId: bp_runtime::ChainId = bp_runtime::BRIDGE_HUB_ROCOCO_CHAIN_ID;
-	pub BridgeWestendToRococoMessagesPalletInstance: InteriorMultiLocation = X1(PalletInstance(<BridgeRococoMessages as PalletInfoAccess>::index() as u8));
+	pub BridgeWestendToRococoMessagesPalletInstance: InteriorLocation = [PalletInstance(<BridgeRococoMessages as PalletInfoAccess>::index() as u8)].into();
 	pub RococoGlobalConsensusNetwork: NetworkId = NetworkId::Rococo;
-	pub RococoGlobalConsensusNetworkLocation: MultiLocation = MultiLocation {
-		parents: 2,
-		interior: X1(GlobalConsensus(RococoGlobalConsensusNetwork::get()))
-	};
+	pub RococoGlobalConsensusNetworkLocation: Location = Location::new(
+		2,
+		[GlobalConsensus(RococoGlobalConsensusNetwork::get())]
+	);
 	// see the `FEE_BOOST_PER_MESSAGE` constant to get the meaning of this value
 	pub PriorityBoostPerMessage: u64 = 182_044_444_444_444;
 
@@ -79,26 +79,26 @@ parameter_types! {
 	pub ActiveOutboundLanesToBridgeHubRococo: &'static [bp_messages::LaneId] = &[XCM_LANE_FOR_ASSET_HUB_WESTEND_TO_ASSET_HUB_ROCOCO];
 	pub const AssetHubWestendToAssetHubRococoMessagesLane: bp_messages::LaneId = XCM_LANE_FOR_ASSET_HUB_WESTEND_TO_ASSET_HUB_ROCOCO;
 	pub FromAssetHubWestendToAssetHubRococoRoute: SenderAndLane = SenderAndLane::new(
-		ParentThen(X1(Parachain(AssetHubWestendParaId::get().into()))).into(),
+		ParentThen([Parachain(AssetHubWestendParaId::get().into())].into()).into(),
 		XCM_LANE_FOR_ASSET_HUB_WESTEND_TO_ASSET_HUB_ROCOCO,
 	);
-	pub ActiveLanes: sp_std::vec::Vec<(SenderAndLane, (NetworkId, InteriorMultiLocation))> = sp_std::vec![
+	pub ActiveLanes: sp_std::vec::Vec<(SenderAndLane, (NetworkId, InteriorLocation))> = sp_std::vec![
 			(
 				FromAssetHubWestendToAssetHubRococoRoute::get(),
-				(RococoGlobalConsensusNetwork::get(), X1(Parachain(AssetHubRococoParaId::get().into())))
+				(RococoGlobalConsensusNetwork::get(), [Parachain(AssetHubRococoParaId::get().into())].into())
 			)
 	];
 
 	pub CongestedMessage: Xcm<()> = build_congestion_message(true).into();
 	pub UncongestedMessage: Xcm<()> = build_congestion_message(false).into();
 
-	pub BridgeHubRococoLocation: MultiLocation = MultiLocation {
-		parents: 2,
-		interior: X2(
+	pub BridgeHubRococoLocation: Location = Location::new(
+		2,
+		[
 			GlobalConsensus(RococoGlobalConsensusNetwork::get()),
 			Parachain(<bp_bridge_hub_rococo::BridgeHubRococo as bp_runtime::Parachain>::PARACHAIN_ID)
-		)
-	};
+		]
+	);
 }
 pub const XCM_LANE_FOR_ASSET_HUB_WESTEND_TO_ASSET_HUB_ROCOCO: LaneId = LaneId([0, 0, 0, 2]);
 
@@ -363,9 +363,9 @@ mod tests {
 
 		assert_eq!(
 			BridgeWestendToRococoMessagesPalletInstance::get(),
-			X1(PalletInstance(
+			[PalletInstance(
 				bp_bridge_hub_westend::WITH_BRIDGE_WESTEND_TO_ROCOCO_MESSAGES_PALLET_INDEX
-			))
+			)]
 		);
 	}
 }

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-westend/src/lib.rs

@@ -352,7 +352,7 @@ impl cumulus_pallet_aura_ext::Config for Runtime {}
 
 parameter_types! {
 	/// The asset ID for the asset that we use to pay for message delivery fees.
-	pub FeeAssetId: AssetId = Concrete(xcm_config::WestendLocation::get());
+	pub FeeAssetId: AssetId = AssetId(xcm_config::WestendLocation::get());
 	/// The base fee for the message delivery fees.
 	pub const BaseDeliveryFee: u128 = CENTS.saturating_mul(3);
 }
@@ -797,28 +797,28 @@ impl_runtime_apis! {
 
 			use pallet_xcm::benchmarking::Pallet as PalletXcmExtrinsicsBenchmark;
 			impl pallet_xcm::benchmarking::Config for Runtime {
-				fn reachable_dest() -> Option<MultiLocation> {
+				fn reachable_dest() -> Option<Location> {
 					Some(Parent.into())
 				}
 
-				fn teleportable_asset_and_dest() -> Option<(MultiAsset, MultiLocation)> {
+				fn teleportable_asset_and_dest() -> Option<(Asset, Location)> {
 					// Relay/native token can be teleported between BH and Relay.
 					Some((
-						MultiAsset {
+						Asset {
 							fun: Fungible(EXISTENTIAL_DEPOSIT),
-							id: Concrete(Parent.into())
+							id: AssetId(Parent.into())
 						},
 						Parent.into(),
 					))
 				}
 
-				fn reserve_transferable_asset_and_dest() -> Option<(MultiAsset, MultiLocation)> {
+				fn reserve_transferable_asset_and_dest() -> Option<(Asset, Location)> {
 					// Reserve transfers are disabled on BH.
 					None
 				}
 
 				fn set_up_complex_asset_transfer(
-				) -> Option<(MultiAssets, u32, MultiLocation, Box<dyn FnOnce()>)> {
+				) -> Option<(Assets, u32, Location, Box<dyn FnOnce()>)> {
 					// BH only supports teleports to system parachain.
 					// Relay/native token can be teleported between BH and Relay.
 					let native_location = Parent.into();
@@ -834,7 +834,7 @@ impl_runtime_apis! {
 			use xcm_config::WestendLocation;
 
 			parameter_types! {
-				pub ExistentialDepositMultiAsset: Option<MultiAsset> = Some((
+				pub ExistentialDepositAsset: Option<Asset> = Some((
 					WestendLocation::get(),
 					ExistentialDeposit::get()
 				).into());
@@ -845,17 +845,17 @@ impl_runtime_apis! {
 				type AccountIdConverter = xcm_config::LocationToAccountId;
 				type DeliveryHelper = cumulus_primitives_utility::ToParentDeliveryHelper<
 					xcm_config::XcmConfig,
-					ExistentialDepositMultiAsset,
+					ExistentialDepositAsset,
 					xcm_config::PriceForParentDelivery,
 				>;
-				fn valid_destination() -> Result<MultiLocation, BenchmarkError> {
+				fn valid_destination() -> Result<Location, BenchmarkError> {
 					Ok(WestendLocation::get())
 				}
-				fn worst_case_holding(_depositable_count: u32) -> MultiAssets {
-					// just concrete assets according to relay chain.
-					let assets: Vec<MultiAsset> = vec![
-						MultiAsset {
-							id: Concrete(WestendLocation::get()),
+				fn worst_case_holding(_depositable_count: u32) -> Assets {
+					// just assets according to relay chain.
+					let assets: Vec<Asset> = vec![
+						Asset {
+							id: AssetId(WestendLocation::get()),
 							fun: Fungible(1_000_000 * UNITS),
 						}
 					];
@@ -864,12 +864,12 @@ impl_runtime_apis! {
 			}
 
 			parameter_types! {
-				pub const TrustedTeleporter: Option<(MultiLocation, MultiAsset)> = Some((
+				pub const TrustedTeleporter: Option<(Location, Asset)> = Some((
 					WestendLocation::get(),
-					MultiAsset { fun: Fungible(UNITS), id: Concrete(WestendLocation::get()) },
+					Asset { fun: Fungible(UNITS), id: AssetId(WestendLocation::get()) },
 				));
 				pub const CheckedAccount: Option<(AccountId, xcm_builder::MintLocation)> = None;
-				pub const TrustedReserve: Option<(MultiLocation, MultiAsset)> = None;
+				pub const TrustedReserve: Option<(Location, Asset)> = None;
 			}
 
 			impl pallet_xcm_benchmarks::fungible::Config for Runtime {
@@ -879,9 +879,9 @@ impl_runtime_apis! {
 				type TrustedTeleporter = TrustedTeleporter;
 				type TrustedReserve = TrustedReserve;
 
-				fn get_multi_asset() -> MultiAsset {
-					MultiAsset {
-						id: Concrete(WestendLocation::get()),
+				fn get_asset() -> Asset {
+					Asset {
+						id: AssetId(WestendLocation::get()),
 						fun: Fungible(UNITS),
 					}
 				}
@@ -895,35 +895,35 @@ impl_runtime_apis! {
 					(0u64, Response::Version(Default::default()))
 				}
 
-				fn worst_case_asset_exchange() -> Result<(MultiAssets, MultiAssets), BenchmarkError> {
+				fn worst_case_asset_exchange() -> Result<(Assets, Assets), BenchmarkError> {
 					Err(BenchmarkError::Skip)
 				}
 
-				fn universal_alias() -> Result<(MultiLocation, Junction), BenchmarkError> {
+				fn universal_alias() -> Result<(Location, Junction), BenchmarkError> {
 					Err(BenchmarkError::Skip)
 				}
 
-				fn transact_origin_and_runtime_call() -> Result<(MultiLocation, RuntimeCall), BenchmarkError> {
+				fn transact_origin_and_runtime_call() -> Result<(Location, RuntimeCall), BenchmarkError> {
 					Ok((WestendLocation::get(), frame_system::Call::remark_with_event { remark: vec![] }.into()))
 				}
 
-				fn subscribe_origin() -> Result<MultiLocation, BenchmarkError> {
+				fn subscribe_origin() -> Result<Location, BenchmarkError> {
 					Ok(WestendLocation::get())
 				}
 
-				fn claimable_asset() -> Result<(MultiLocation, MultiLocation, MultiAssets), BenchmarkError> {
+				fn claimable_asset() -> Result<(Location, Location, Assets), BenchmarkError> {
 					let origin = WestendLocation::get();
-					let assets: MultiAssets = (Concrete(WestendLocation::get()), 1_000 * UNITS).into();
-					let ticket = MultiLocation { parents: 0, interior: Here };
+					let assets: Assets = (AssetId(WestendLocation::get()), 1_000 * UNITS).into();
+					let ticket = Location { parents: 0, interior: Here };
 					Ok((origin, ticket, assets))
 				}
 
-				fn unlockable_asset() -> Result<(MultiLocation, MultiLocation, MultiAsset), BenchmarkError> {
+				fn unlockable_asset() -> Result<(Location, Location, Asset), BenchmarkError> {
 					Err(BenchmarkError::Skip)
 				}
 
 				fn export_message_origin_and_destination(
-				) -> Result<(MultiLocation, NetworkId, InteriorMultiLocation), BenchmarkError> {
+				) -> Result<(Location, NetworkId, InteriorLocation), BenchmarkError> {
 					// save XCM version for remote bridge hub
 					let _ = PolkadotXcm::force_xcm_version(
 						RuntimeOrigin::root(),
@@ -943,12 +943,12 @@ impl_runtime_apis! {
 						(
 							bridge_to_rococo_config::FromAssetHubWestendToAssetHubRococoRoute::get().location,
 							NetworkId::Rococo,
-							X1(Parachain(bridge_to_rococo_config::AssetHubRococoParaId::get().into()))
+							[Parachain(bridge_to_rococo_config::AssetHubRococoParaId::get().into())].into()
 						)
 					)
 				}
 
-				fn alias_origin() -> Result<(MultiLocation, MultiLocation), BenchmarkError> {
+				fn alias_origin() -> Result<(Location, Location), BenchmarkError> {
 					Err(BenchmarkError::Skip)
 				}
 			}
@@ -995,7 +995,7 @@ impl_runtime_apis! {
 						Runtime,
 						bridge_to_rococo_config::BridgeGrandpaRococoInstance,
 						bridge_to_rococo_config::WithBridgeHubRococoMessageBridge,
-					>(params, generate_xcm_builder_bridge_message_sample(X2(GlobalConsensus(Westend), Parachain(42))))
+					>(params, generate_xcm_builder_bridge_message_sample([GlobalConsensus(Westend), Parachain(42)].into()))
 				}
 
 				fn prepare_message_delivery_proof(

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-westend/src/weights/xcm/mod.rs

@@ -25,14 +25,14 @@ use pallet_xcm_benchmarks_generic::WeightInfo as XcmGeneric;
 use sp_std::prelude::*;
 use xcm::{latest::prelude::*, DoubleEncoded};
 
-trait WeighMultiAssets {
-	fn weigh_multi_assets(&self, weight: Weight) -> Weight;
+trait WeighAssets {
+	fn weigh_assets(&self, weight: Weight) -> Weight;
 }
 
 const MAX_ASSETS: u64 = 100;
 
-impl WeighMultiAssets for MultiAssetFilter {
-	fn weigh_multi_assets(&self, weight: Weight) -> Weight {
+impl WeighAssets for AssetFilter {
+	fn weigh_assets(&self, weight: Weight) -> Weight {
 		match self {
 			Self::Definite(assets) => weight.saturating_mul(assets.inner().iter().count() as u64),
 			Self::Wild(asset) => match asset {
@@ -51,40 +51,36 @@ impl WeighMultiAssets for MultiAssetFilter {
 	}
 }
 
-impl WeighMultiAssets for MultiAssets {
-	fn weigh_multi_assets(&self, weight: Weight) -> Weight {
+impl WeighAssets for Assets {
+	fn weigh_assets(&self, weight: Weight) -> Weight {
 		weight.saturating_mul(self.inner().iter().count() as u64)
 	}
 }
 
 pub struct BridgeHubWestendXcmWeight<Call>(core::marker::PhantomData<Call>);
 impl<Call> XcmWeightInfo<Call> for BridgeHubWestendXcmWeight<Call> {
-	fn withdraw_asset(assets: &MultiAssets) -> Weight {
-		assets.weigh_multi_assets(XcmFungibleWeight::<Runtime>::withdraw_asset())
+	fn withdraw_asset(assets: &Assets) -> Weight {
+		assets.weigh_assets(XcmFungibleWeight::<Runtime>::withdraw_asset())
 	}
-	fn reserve_asset_deposited(assets: &MultiAssets) -> Weight {
-		assets.weigh_multi_assets(XcmFungibleWeight::<Runtime>::reserve_asset_deposited())
+	fn reserve_asset_deposited(assets: &Assets) -> Weight {
+		assets.weigh_assets(XcmFungibleWeight::<Runtime>::reserve_asset_deposited())
 	}
-	fn receive_teleported_asset(assets: &MultiAssets) -> Weight {
-		assets.weigh_multi_assets(XcmFungibleWeight::<Runtime>::receive_teleported_asset())
+	fn receive_teleported_asset(assets: &Assets) -> Weight {
+		assets.weigh_assets(XcmFungibleWeight::<Runtime>::receive_teleported_asset())
 	}
 	fn query_response(
 		_query_id: &u64,
 		_response: &Response,
 		_max_weight: &Weight,
-		_querier: &Option<MultiLocation>,
+		_querier: &Option<Location>,
 	) -> Weight {
 		XcmGeneric::<Runtime>::query_response()
 	}
-	fn transfer_asset(assets: &MultiAssets, _dest: &MultiLocation) -> Weight {
-		assets.weigh_multi_assets(XcmFungibleWeight::<Runtime>::transfer_asset())
+	fn transfer_asset(assets: &Assets, _dest: &Location) -> Weight {
+		assets.weigh_assets(XcmFungibleWeight::<Runtime>::transfer_asset())
 	}
-	fn transfer_reserve_asset(
-		assets: &MultiAssets,
-		_dest: &MultiLocation,
-		_xcm: &Xcm<()>,
-	) -> Weight {
-		assets.weigh_multi_assets(XcmFungibleWeight::<Runtime>::transfer_reserve_asset())
+	fn transfer_reserve_asset(assets: &Assets, _dest: &Location, _xcm: &Xcm<()>) -> Weight {
+		assets.weigh_assets(XcmFungibleWeight::<Runtime>::transfer_reserve_asset())
 	}
 	fn transact(
 		_origin_type: &OriginKind,
@@ -112,44 +108,36 @@ impl<Call> XcmWeightInfo<Call> for BridgeHubWestendXcmWeight<Call> {
 	fn clear_origin() -> Weight {
 		XcmGeneric::<Runtime>::clear_origin()
 	}
-	fn descend_origin(_who: &InteriorMultiLocation) -> Weight {
+	fn descend_origin(_who: &InteriorLocation) -> Weight {
 		XcmGeneric::<Runtime>::descend_origin()
 	}
 	fn report_error(_query_response_info: &QueryResponseInfo) -> Weight {
 		XcmGeneric::<Runtime>::report_error()
 	}
 
-	fn deposit_asset(assets: &MultiAssetFilter, _dest: &MultiLocation) -> Weight {
-		assets.weigh_multi_assets(XcmFungibleWeight::<Runtime>::deposit_asset())
+	fn deposit_asset(assets: &AssetFilter, _dest: &Location) -> Weight {
+		assets.weigh_assets(XcmFungibleWeight::<Runtime>::deposit_asset())
 	}
-	fn deposit_reserve_asset(
-		assets: &MultiAssetFilter,
-		_dest: &MultiLocation,
-		_xcm: &Xcm<()>,
-	) -> Weight {
-		assets.weigh_multi_assets(XcmFungibleWeight::<Runtime>::deposit_reserve_asset())
+	fn deposit_reserve_asset(assets: &AssetFilter, _dest: &Location, _xcm: &Xcm<()>) -> Weight {
+		assets.weigh_assets(XcmFungibleWeight::<Runtime>::deposit_reserve_asset())
 	}
-	fn exchange_asset(_give: &MultiAssetFilter, _receive: &MultiAssets, _maximal: &bool) -> Weight {
+	fn exchange_asset(_give: &AssetFilter, _receive: &Assets, _maximal: &bool) -> Weight {
 		Weight::MAX
 	}
 	fn initiate_reserve_withdraw(
-		assets: &MultiAssetFilter,
-		_reserve: &MultiLocation,
+		assets: &AssetFilter,
+		_reserve: &Location,
 		_xcm: &Xcm<()>,
 	) -> Weight {
-		assets.weigh_multi_assets(XcmFungibleWeight::<Runtime>::initiate_reserve_withdraw())
+		assets.weigh_assets(XcmFungibleWeight::<Runtime>::initiate_reserve_withdraw())
 	}
-	fn initiate_teleport(
-		assets: &MultiAssetFilter,
-		_dest: &MultiLocation,
-		_xcm: &Xcm<()>,
-	) -> Weight {
-		assets.weigh_multi_assets(XcmFungibleWeight::<Runtime>::initiate_teleport())
+	fn initiate_teleport(assets: &AssetFilter, _dest: &Location, _xcm: &Xcm<()>) -> Weight {
+		assets.weigh_assets(XcmFungibleWeight::<Runtime>::initiate_teleport())
 	}
-	fn report_holding(_response_info: &QueryResponseInfo, _assets: &MultiAssetFilter) -> Weight {
+	fn report_holding(_response_info: &QueryResponseInfo, _assets: &AssetFilter) -> Weight {
 		XcmGeneric::<Runtime>::report_holding()
 	}
-	fn buy_execution(_fees: &MultiAsset, _weight_limit: &WeightLimit) -> Weight {
+	fn buy_execution(_fees: &Asset, _weight_limit: &WeightLimit) -> Weight {
 		XcmGeneric::<Runtime>::buy_execution()
 	}
 	fn refund_surplus() -> Weight {
@@ -164,7 +152,7 @@ impl<Call> XcmWeightInfo<Call> for BridgeHubWestendXcmWeight<Call> {
 	fn clear_error() -> Weight {
 		XcmGeneric::<Runtime>::clear_error()
 	}
-	fn claim_asset(_assets: &MultiAssets, _ticket: &MultiLocation) -> Weight {
+	fn claim_asset(_assets: &Assets, _ticket: &Location) -> Weight {
 		XcmGeneric::<Runtime>::claim_asset()
 	}
 	fn trap(_code: &u64) -> Weight {
@@ -176,13 +164,13 @@ impl<Call> XcmWeightInfo<Call> for BridgeHubWestendXcmWeight<Call> {
 	fn unsubscribe_version() -> Weight {
 		XcmGeneric::<Runtime>::unsubscribe_version()
 	}
-	fn burn_asset(assets: &MultiAssets) -> Weight {
-		assets.weigh_multi_assets(XcmGeneric::<Runtime>::burn_asset())
+	fn burn_asset(assets: &Assets) -> Weight {
+		assets.weigh_assets(XcmGeneric::<Runtime>::burn_asset())
 	}
-	fn expect_asset(assets: &MultiAssets) -> Weight {
-		assets.weigh_multi_assets(XcmGeneric::<Runtime>::expect_asset())
+	fn expect_asset(assets: &Assets) -> Weight {
+		assets.weigh_assets(XcmGeneric::<Runtime>::expect_asset())
 	}
-	fn expect_origin(_origin: &Option<MultiLocation>) -> Weight {
+	fn expect_origin(_origin: &Option<Location>) -> Weight {
 		XcmGeneric::<Runtime>::expect_origin()
 	}
 	fn expect_error(_error: &Option<(u32, XcmError)>) -> Weight {
@@ -216,16 +204,16 @@ impl<Call> XcmWeightInfo<Call> for BridgeHubWestendXcmWeight<Call> {
 		let inner_encoded_len = inner.encode().len() as u32;
 		XcmGeneric::<Runtime>::export_message(inner_encoded_len)
 	}
-	fn lock_asset(_: &MultiAsset, _: &MultiLocation) -> Weight {
+	fn lock_asset(_: &Asset, _: &Location) -> Weight {
 		Weight::MAX
 	}
-	fn unlock_asset(_: &MultiAsset, _: &MultiLocation) -> Weight {
+	fn unlock_asset(_: &Asset, _: &Location) -> Weight {
 		Weight::MAX
 	}
-	fn note_unlockable(_: &MultiAsset, _: &MultiLocation) -> Weight {
+	fn note_unlockable(_: &Asset, _: &Location) -> Weight {
 		Weight::MAX
 	}
-	fn request_unlock(_: &MultiAsset, _: &MultiLocation) -> Weight {
+	fn request_unlock(_: &Asset, _: &Location) -> Weight {
 		Weight::MAX
 	}
 	fn set_fees_mode(_: &bool) -> Weight {
@@ -237,11 +225,11 @@ impl<Call> XcmWeightInfo<Call> for BridgeHubWestendXcmWeight<Call> {
 	fn clear_topic() -> Weight {
 		XcmGeneric::<Runtime>::clear_topic()
 	}
-	fn alias_origin(_: &MultiLocation) -> Weight {
+	fn alias_origin(_: &Location) -> Weight {
 		// XCM Executor does not currently support alias origin operations
 		Weight::MAX
 	}
-	fn unpaid_execution(_: &WeightLimit, _: &Option<MultiLocation>) -> Weight {
+	fn unpaid_execution(_: &WeightLimit, _: &Option<Location>) -> Weight {
 		XcmGeneric::<Runtime>::unpaid_execution()
 	}
 }

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-westend/src/xcm_config.rs

@@ -21,7 +21,7 @@ use super::{
 };
 use crate::bridge_common_config::{DeliveryRewardInBalance, RequiredStakeForStakeAndSlash};
 use frame_support::{
-	match_types, parameter_types,
+	parameter_types,
 	traits::{ConstU32, Contains, Equals, Everything, Nothing},
 };
 use frame_system::EnsureRoot;
@@ -52,18 +52,18 @@ use xcm_builder::{
 use xcm_executor::{traits::WithOriginFilter, XcmExecutor};
 
 parameter_types! {
-	pub const WestendLocation: MultiLocation = MultiLocation::parent();
+	pub const WestendLocation: Location = Location::parent();
 	pub const RelayNetwork: NetworkId = NetworkId::Westend;
 	pub RelayChainOrigin: RuntimeOrigin = cumulus_pallet_xcm::Origin::Relay.into();
-	pub UniversalLocation: InteriorMultiLocation =
-		X2(GlobalConsensus(RelayNetwork::get()), Parachain(ParachainInfo::parachain_id().into()));
+	pub UniversalLocation: InteriorLocation =
+		[GlobalConsensus(RelayNetwork::get()), Parachain(ParachainInfo::parachain_id().into())].into();
 	pub const MaxInstructions: u32 = 100;
 	pub const MaxAssetsIntoHolding: u32 = 64;
 	pub TreasuryAccount: AccountId = TREASURY_PALLET_ID.into_account_truncating();
-	pub RelayTreasuryLocation: MultiLocation = (Parent, PalletInstance(westend_runtime_constants::TREASURY_PALLET_ID)).into();
+	pub RelayTreasuryLocation: Location = (Parent, PalletInstance(westend_runtime_constants::TREASURY_PALLET_ID)).into();
 }
 
-/// Type for specifying how a `MultiLocation` can be converted into an `AccountId`. This is used
+/// Type for specifying how a `Location` can be converted into an `AccountId`. This is used
 /// when determining ownership of accounts for asset transacting and when attempting to use XCM
 /// `Transact` in order to determine the dispatch Origin.
 pub type LocationToAccountId = (
@@ -82,7 +82,7 @@ pub type CurrencyTransactor = CurrencyAdapter<
 	Balances,
 	// Use this currency when it is a fungible asset matching the given location or name:
 	IsConcrete<WestendLocation>,
-	// Do a simple punn to convert an AccountId32 MultiLocation into a native chain account ID:
+	// Do a simple punn to convert an AccountId32 Location into a native chain account ID:
 	LocationToAccountId,
 	// Our chain's account ID type (we can't get away without mentioning it explicitly):
 	AccountId,
@@ -114,11 +114,11 @@ pub type XcmOriginToTransactDispatchOrigin = (
 	XcmPassthrough<RuntimeOrigin>,
 );
 
-match_types! {
-	pub type ParentOrParentsPlurality: impl Contains<MultiLocation> = {
-		MultiLocation { parents: 1, interior: Here } |
-		MultiLocation { parents: 1, interior: X1(Plurality { .. }) }
-	};
+pub struct ParentOrParentsPlurality;
+impl Contains<Location> for ParentOrParentsPlurality {
+	fn contains(location: &Location) -> bool {
+		matches!(location.unpack(), (1, []) | (1, [Plurality { .. }]))
+	}
 }
 
 /// A call filter for the XCM Transact instruction. This is a temporary measure until we properly
@@ -270,7 +270,7 @@ impl xcm_executor::Config for XcmConfig {
 pub type PriceForParentDelivery =
 	ExponentialPrice<FeeAssetId, BaseDeliveryFee, TransactionByteFee, ParachainSystem>;
 
-/// Converts a local signed origin into an XCM multilocation.
+/// Converts a local signed origin into an XCM location.
 /// Forms the basis for local origins sending/executing XCMs.
 pub type LocalOriginToLocation = SignedToAccountId32<RuntimeOrigin, AccountId, RelayNetwork>;
 

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-westend/tests/tests.rs

@@ -207,7 +207,7 @@ fn handle_export_message_from_system_parachain_add_to_outbound_queue_works() {
 					_ => None,
 				}
 			}),
-			|| ExportMessage { network: Rococo, destination: X1(Parachain(bridge_to_rococo_config::AssetHubRococoParaId::get().into())), xcm: Xcm(vec![]) },
+			|| ExportMessage { network: Rococo, destination: [Parachain(bridge_to_rococo_config::AssetHubRococoParaId::get().into())].into(), xcm: Xcm(vec![]) },
 			XCM_LANE_FOR_ASSET_HUB_WESTEND_TO_ASSET_HUB_ROCOCO,
 			Some((WestendLocation::get(), ExistentialDeposit::get()).into()),
 			// value should be >= than value generated by `can_calculate_weight_for_paid_export_message_with_reserve_transfer`