move generics of election trait to associated types (#10475)

* move generics of election trait to associated types

* fix doctest

substrate/frame/election-provider-multi-phase/src/benchmarking.rs

@@ -289,7 +289,7 @@ frame_benchmarking::benchmarks! {
 		assert!(<Snapshot<T>>::get().is_some());
 		assert!(<SnapshotMetadata<T>>::get().is_some());
 	}: {
-		assert_ok!(<MultiPhase<T> as ElectionProvider<T::AccountId, T::BlockNumber>>::elect());
+		assert_ok!(<MultiPhase<T> as ElectionProvider>::elect());
 	} verify {
 		assert!(<MultiPhase<T>>::queued_solution().is_none());
 		assert!(<DesiredTargets<T>>::get().is_none());

substrate/frame/election-provider-multi-phase/src/lib.rs

@@ -139,7 +139,7 @@
 //! To generate an emergency solution, one must only provide one argument: [`Supports`]. This is
 //! essentially a collection of elected winners for the election, and voters who support them. The
 //! supports can be generated by any means. In the simplest case, it could be manual. For example,
-//! in the case of massive network failure or misbehaviour, [`Config::ForceOrigin`] might decide to
+//! in the case of massive network failure or misbehavior, [`Config::ForceOrigin`] might decide to
 //! select only a small number of emergency winners (which would greatly restrict the next validator
 //! set, if this pallet is used with `pallet-staking`). If the failure is for other technical
 //! reasons, then a simple and safe way to generate supports is using the staking-miner binary
@@ -286,10 +286,7 @@ pub type SolutionTargetIndexOf<T> = <SolutionOf<T> as NposSolution>::TargetIndex
 /// The accuracy of the election, when submitted from offchain. Derived from [`SolutionOf`].
 pub type SolutionAccuracyOf<T> = <SolutionOf<T> as NposSolution>::Accuracy;
 /// The fallback election type.
-pub type FallbackErrorOf<T> = <<T as crate::Config>::Fallback as ElectionProvider<
-	<T as frame_system::Config>::AccountId,
-	<T as frame_system::Config>::BlockNumber,
->>::Error;
+pub type FallbackErrorOf<T> = <<T as crate::Config>::Fallback as ElectionProvider>::Error;
 
 /// Configuration for the benchmarks of the pallet.
 pub trait BenchmarkingConfig {
@@ -312,7 +309,9 @@ pub trait BenchmarkingConfig {
 /// A fallback implementation that transitions the pallet to the emergency phase.
 pub struct NoFallback<T>(sp_std::marker::PhantomData<T>);
 
-impl<T: Config> ElectionProvider<T::AccountId, T::BlockNumber> for NoFallback<T> {
+impl<T: Config> ElectionProvider for NoFallback<T> {
+	type AccountId = T::AccountId;
+	type BlockNumber = T::BlockNumber;
 	type DataProvider = T::DataProvider;
 	type Error = &'static str;
 
@@ -654,7 +653,10 @@ pub mod pallet {
 		type MinerMaxLength: Get<u32>;
 
 		/// Something that will provide the election data.
-		type DataProvider: ElectionDataProvider<Self::AccountId, Self::BlockNumber>;
+		type DataProvider: ElectionDataProvider<
+			AccountId = Self::AccountId,
+			BlockNumber = Self::BlockNumber,
+		>;
 
 		/// The solution type.
 		type Solution: codec::Codec
@@ -669,8 +671,8 @@ pub mod pallet {
 
 		/// Configuration for the fallback
 		type Fallback: ElectionProvider<
-			Self::AccountId,
-			Self::BlockNumber,
+			AccountId = Self::AccountId,
+			BlockNumber = Self::BlockNumber,
 			DataProvider = Self::DataProvider,
 		>;
 
@@ -818,7 +820,7 @@ pub mod pallet {
 			// NOTE that this pallet does not really need to enforce this in runtime. The
 			// solution cannot represent any voters more than `LIMIT` anyhow.
 			assert_eq!(
-				<T::DataProvider as ElectionDataProvider<T::AccountId, T::BlockNumber>>::MAXIMUM_VOTES_PER_VOTER,
+				<T::DataProvider as ElectionDataProvider>::MAXIMUM_VOTES_PER_VOTER,
 				<SolutionOf<T> as NposSolution>::LIMIT as u32,
 			);
 		}
@@ -1492,7 +1494,9 @@ impl<T: Config> Pallet<T> {
 	}
 }
 
-impl<T: Config> ElectionProvider<T::AccountId, T::BlockNumber> for Pallet<T> {
+impl<T: Config> ElectionProvider for Pallet<T> {
+	type AccountId = T::AccountId;
+	type BlockNumber = T::BlockNumber;
 	type Error = ElectionError<T>;
 	type DataProvider = T::DataProvider;
 

substrate/frame/election-provider-multi-phase/src/mock.rs

@@ -285,7 +285,9 @@ impl onchain::Config for Runtime {
 }
 
 pub struct MockFallback;
-impl ElectionProvider<AccountId, u64> for MockFallback {
+impl ElectionProvider for MockFallback {
+	type AccountId = AccountId;
+	type BlockNumber = u64;
 	type Error = &'static str;
 	type DataProvider = StakingMock;
 
@@ -438,7 +440,9 @@ pub type Extrinsic = sp_runtime::testing::TestXt<Call, ()>;
 pub struct ExtBuilder {}
 
 pub struct StakingMock;
-impl ElectionDataProvider<AccountId, u64> for StakingMock {
+impl ElectionDataProvider for StakingMock {
+	type AccountId = AccountId;
+	type BlockNumber = u64;
 	const MAXIMUM_VOTES_PER_VOTER: u32 = <TestNposSolution as NposSolution>::LIMIT as u32;
 	fn targets(maybe_max_len: Option<usize>) -> data_provider::Result<Vec<AccountId>> {
 		let targets = Targets::get();