Add FungibleAdapter (paritytech#2684)

In the move from the old `Currency` traits to the new `fungible/s`
family of traits, we already had the `FungiblesAdapter` and
`NonFungiblesAdapter` for multiple fungible and non fungible assets
respectively. However, for handling only one fungible asset, we were
missing a `FungibleAdapter`, and so used the old `CurrencyAdapter`
instead. This PR aims to fill in that gap, and provide the new adapter
for more updated examples.

I marked the old `CurrencyAdapter` as deprecated as part of this PR, and
I'll change it to the new `FungibleAdapter` in a following PR.
The two stages are separated so as to not bloat this PR with some name
fixes in tests.

---------

Co-authored-by: command-bot <>

substrate/frame/contracts/mock-network/src/parachain.rs

@@ -37,12 +37,13 @@ use sp_runtime::traits::{Get, IdentityLookup, MaybeEquivalence};
 
 use sp_std::prelude::*;
 use xcm::latest::prelude::*;
+#[allow(deprecated)]
+use xcm_builder::CurrencyAdapter as XcmCurrencyAdapter;
 use xcm_builder::{
 	AccountId32Aliases, AllowExplicitUnpaidExecutionFrom, AllowTopLevelPaidExecutionFrom,
-	ConvertedConcreteId, CurrencyAdapter as XcmCurrencyAdapter, EnsureXcmOrigin,
-	FixedRateOfFungible, FixedWeightBounds, FungiblesAdapter, IsConcrete, NativeAsset, NoChecking,
-	ParentAsSuperuser, ParentIsPreset, SignedAccountId32AsNative, SignedToAccountId32,
-	SovereignSignedViaLocation, WithComputedOrigin,
+	ConvertedConcreteId, EnsureXcmOrigin, FixedRateOfFungible, FixedWeightBounds, FungiblesAdapter,
+	IsConcrete, NativeAsset, NoChecking, ParentAsSuperuser, ParentIsPreset,
+	SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation, WithComputedOrigin,
 };
 use xcm_executor::{traits::JustTry, Config, XcmExecutor};
 
@@ -183,6 +184,7 @@ pub fn estimate_fee_for_weight(weight: Weight) -> u128 {
 		units_per_mb * (weight.proof_size() as u128) / (WEIGHT_PROOF_SIZE_PER_MB as u128)
 }
 
+#[allow(deprecated)]
 pub type LocalBalancesTransactor =
 	XcmCurrencyAdapter<Balances, IsConcrete<TokenLocation>, SovereignAccountOf, AccountId, ()>;
 

substrate/frame/contracts/mock-network/src/relay_chain.rs

@@ -29,12 +29,14 @@ use sp_runtime::traits::IdentityLookup;
 use polkadot_parachain_primitives::primitives::Id as ParaId;
 use polkadot_runtime_parachains::{configuration, origin, shared};
 use xcm::latest::prelude::*;
+#[allow(deprecated)]
+use xcm_builder::CurrencyAdapter as XcmCurrencyAdapter;
 use xcm_builder::{
 	AccountId32Aliases, AllowExplicitUnpaidExecutionFrom, AllowSubscriptionsFrom,
 	AllowTopLevelPaidExecutionFrom, ChildParachainAsNative, ChildParachainConvertsVia,
-	ChildSystemParachainAsSuperuser, CurrencyAdapter as XcmCurrencyAdapter, DescribeAllTerminal,
-	DescribeFamily, FixedRateOfFungible, FixedWeightBounds, HashedDescription, IsConcrete,
-	SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation, WithComputedOrigin,
+	ChildSystemParachainAsSuperuser, DescribeAllTerminal, DescribeFamily, FixedRateOfFungible,
+	FixedWeightBounds, HashedDescription, IsConcrete, SignedAccountId32AsNative,
+	SignedToAccountId32, SovereignSignedViaLocation, WithComputedOrigin,
 };
 use xcm_executor::{Config, XcmExecutor};
 
@@ -116,6 +118,7 @@ pub type SovereignAccountOf = (
 	ChildParachainConvertsVia<ParaId, AccountId>,
 );
 
+#[allow(deprecated)]
 pub type LocalBalancesTransactor =
 	XcmCurrencyAdapter<Balances, IsConcrete<TokenLocation>, SovereignAccountOf, AccountId, ()>;