Moving NposSolution to frame (#11031)

* Move `sp-npos-elections-solution-type`
to `frame-election-provider-support`
First stab at it, will need to amend some more stuff

* Fixing tests

* Fixing tests

* Fixing cargo.toml for std configuration

* fmt

* Committing suggested changes
renaming, and re exporting macro.

* Removing unneeded imports

* Move `NposSolution` to frame

* Removing `npos_election` dependencies
Implementing _fpes better

* some feedback for moving NPoSSolution to frame

* fmt

* more formatting

* Fixed some imports and fmt

* Fixing docs

Co-authored-by: kianenigma <kian@parity.io>

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

@@ -28,7 +28,6 @@ use frame_support::{
 use frame_system::RawOrigin;
 use rand::{prelude::SliceRandom, rngs::SmallRng, SeedableRng};
 use sp_arithmetic::{per_things::Percent, traits::One};
-use sp_npos_elections::IndexAssignment;
 use sp_runtime::InnerOf;
 
 const SEED: u32 = 999;
@@ -461,6 +460,7 @@ frame_benchmarking::benchmarks! {
 			T::BenchmarkingConfig::DESIRED_TARGETS[1];
 		// Subtract this percentage from the actual encoded size
 		let f in 0 .. 95;
+		use frame_election_provider_support::IndexAssignment;
 
 		// Compute a random solution, then work backwards to get the lists of voters, targets, and
 		// assignments

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

@@ -231,7 +231,7 @@
 
 use codec::{Decode, Encode};
 use frame_election_provider_support::{
-	ElectionDataProvider, ElectionProvider, InstantElectionProvider,
+	ElectionDataProvider, ElectionProvider, InstantElectionProvider, NposSolution,
 };
 use frame_support::{
 	dispatch::DispatchResultWithPostInfo,
@@ -246,8 +246,7 @@ use sp_arithmetic::{
 	UpperOf,
 };
 use sp_npos_elections::{
-	assignment_ratio_to_staked_normalized, ElectionScore, EvaluateSupport, NposSolution, Supports,
-	VoteWeight,
+	assignment_ratio_to_staked_normalized, ElectionScore, EvaluateSupport, Supports, VoteWeight,
 };
 use sp_runtime::{
 	traits::Bounded,

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

@@ -18,7 +18,7 @@
 use super::*;
 use crate as multi_phase;
 use frame_election_provider_support::{
-	data_provider, onchain, ElectionDataProvider, SequentialPhragmen,
+	data_provider, onchain, ElectionDataProvider, NposSolution, SequentialPhragmen,
 };
 pub use frame_support::{assert_noop, assert_ok};
 use frame_support::{
@@ -38,7 +38,7 @@ use sp_core::{
 };
 use sp_npos_elections::{
 	assignment_ratio_to_staked_normalized, seq_phragmen, to_supports, ElectionResult,
-	EvaluateSupport, ExtendedBalance, NposSolution,
+	EvaluateSupport, ExtendedBalance,
 };
 use sp_runtime::{
 	testing::Header,

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

@@ -23,12 +23,13 @@ use crate::{
 	SolutionOrSnapshotSize, Weight, WeightInfo,
 };
 use codec::{Decode, Encode, HasCompact};
+use frame_election_provider_support::NposSolution;
 use frame_support::{
 	storage::bounded_btree_map::BoundedBTreeMap,
 	traits::{defensive_prelude::*, Currency, Get, OnUnbalanced, ReservableCurrency},
 };
 use sp_arithmetic::traits::SaturatedConversion;
-use sp_npos_elections::{ElectionScore, NposSolution};
+use sp_npos_elections::ElectionScore;
 use sp_runtime::{
 	traits::{Saturating, Zero},
 	RuntimeDebug,

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

@@ -23,12 +23,11 @@ use crate::{
 	WeightInfo,
 };
 use codec::Encode;
-use frame_election_provider_support::{NposSolver, PerThing128};
+use frame_election_provider_support::{NposSolution, NposSolver, PerThing128};
 use frame_support::{dispatch::DispatchResult, ensure, traits::Get};
 use frame_system::offchain::SubmitTransaction;
 use sp_npos_elections::{
 	assignment_ratio_to_staked_normalized, assignment_staked_to_ratio_normalized, ElectionResult,
-	NposSolution,
 };
 use sp_runtime::{
 	offchain::storage::{MutateStorageError, StorageValueRef},
@@ -52,9 +51,9 @@ pub type VoterOf<T> = frame_election_provider_support::VoterOf<<T as Config>::Da
 pub type Assignment<T> =
 	sp_npos_elections::Assignment<<T as frame_system::Config>::AccountId, SolutionAccuracyOf<T>>;
 
-/// The [`IndexAssignment`][sp_npos_elections::IndexAssignment] type specialized for a particular
-/// runtime `T`.
-pub type IndexAssignmentOf<T> = sp_npos_elections::IndexAssignmentOf<SolutionOf<T>>;
+/// The [`IndexAssignment`][frame_election_provider_support::IndexAssignment] type specialized for a
+/// particular runtime `T`.
+pub type IndexAssignmentOf<T> = frame_election_provider_support::IndexAssignmentOf<SolutionOf<T>>;
 
 /// Error type of the pallet's [`crate::Config::Solver`].
 pub type SolverErrorOf<T> = <<T as Config>::Solver as NposSolver>::Error;
@@ -742,10 +741,11 @@ mod tests {
 	};
 	use codec::Decode;
 	use frame_benchmarking::Zero;
+	use frame_election_provider_support::IndexAssignment;
 	use frame_support::{
 		assert_noop, assert_ok, bounded_vec, dispatch::Dispatchable, traits::OffchainWorker,
 	};
-	use sp_npos_elections::{ElectionScore, IndexAssignment};
+	use sp_npos_elections::ElectionScore;
 	use sp_runtime::{
 		offchain::storage_lock::{BlockAndTime, StorageLock},
 		traits::ValidateUnsigned,