sp-std removal from substrate/primitives (#3274)

This PR removes sp-std crate from substrate/primitives sub-directories.

For now crates that have `pub use` of sp-std or export macros that would
necessitate users of the macros to `extern crate alloc` have been
excluded from this PR.

There should be no breaking changes in this PR.

---------

Co-authored-by: Koute <koute@users.noreply.github.com>

substrate/primitives/npos-elections/src/assignments.rs

@@ -18,6 +18,7 @@
 //! Structs and helpers for distributing a voter's stake among various winners.
 
 use crate::{ExtendedBalance, IdentifierT, PerThing128};
+use alloc::vec::Vec;
 #[cfg(feature = "serde")]
 use codec::{Decode, Encode};
 use sp_arithmetic::{
@@ -25,7 +26,6 @@ use sp_arithmetic::{
 	Normalizable, PerThing,
 };
 use sp_core::RuntimeDebug;
-use sp_std::vec::Vec;
 
 /// A voter's stake assignment among a set of targets, represented as ratios.
 #[derive(RuntimeDebug, Clone, Default)]

substrate/primitives/npos-elections/src/balancing.rs

@@ -27,8 +27,8 @@
 //! See [`balance`] for more information.
 
 use crate::{BalancingConfig, Edge, ExtendedBalance, IdentifierT, Voter};
+use alloc::vec::Vec;
 use sp_arithmetic::traits::Zero;
-use sp_std::prelude::*;
 
 /// Balance the weight distribution of a given `voters` at most `iterations` times, or up until the
 /// point where the biggest difference created per iteration of all stakes is `tolerance`. If this

substrate/primitives/npos-elections/src/helpers.rs

@@ -18,8 +18,8 @@
 //! Helper methods for npos-elections.
 
 use crate::{Assignment, Error, IdentifierT, PerThing128, StakedAssignment, VoteWeight};
+use alloc::vec::Vec;
 use sp_arithmetic::PerThing;
-use sp_std::prelude::*;
 
 /// Converts a vector of ratio assignments into ones with absolute budget value.
 ///

substrate/primitives/npos-elections/src/lib.rs

@@ -74,15 +74,16 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
+extern crate alloc;
+
+use alloc::{collections::btree_map::BTreeMap, rc::Rc, vec, vec::Vec};
 use codec::{Decode, Encode, MaxEncodedLen};
+use core::{cell::RefCell, cmp::Ordering};
 use scale_info::TypeInfo;
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 use sp_arithmetic::{traits::Zero, Normalizable, PerThing, Rational128, ThresholdOrd};
 use sp_core::{bounded::BoundedVec, RuntimeDebug};
-use sp_std::{
-	cell::RefCell, cmp::Ordering, collections::btree_map::BTreeMap, prelude::*, rc::Rc, vec,
-};
 
 #[cfg(test)]
 mod mock;
@@ -198,7 +199,7 @@ impl ElectionScore {
 	}
 }
 
-impl sp_std::cmp::Ord for ElectionScore {
+impl core::cmp::Ord for ElectionScore {
 	fn cmp(&self, other: &Self) -> Ordering {
 		// we delegate this to the lexicographic cmp of slices`, and to incorporate that we want the
 		// third element to be minimized, we swap them.
@@ -210,7 +211,7 @@ impl sp_std::cmp::Ord for ElectionScore {
 	}
 }
 
-impl sp_std::cmp::PartialOrd for ElectionScore {
+impl core::cmp::PartialOrd for ElectionScore {
 	fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
 		Some(self.cmp(other))
 	}
@@ -278,8 +279,8 @@ impl<AccountId: Clone> Edge<AccountId> {
 }
 
 #[cfg(feature = "std")]
-impl<A: IdentifierT> sp_std::fmt::Debug for Edge<A> {
-	fn fmt(&self, f: &mut sp_std::fmt::Formatter<'_>) -> sp_std::fmt::Result {
+impl<A: IdentifierT> core::fmt::Debug for Edge<A> {
+	fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 		write!(f, "Edge({:?}, weight = {:?})", self.who, self.weight)
 	}
 }
@@ -299,7 +300,7 @@ pub struct Voter<AccountId> {
 
 #[cfg(feature = "std")]
 impl<A: IdentifierT> std::fmt::Debug for Voter<A> {
-	fn fmt(&self, f: &mut sp_std::fmt::Formatter<'_>) -> sp_std::fmt::Result {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 		write!(f, "Voter({:?}, budget = {}, edges = {:?})", self.who, self.budget, self.edges)
 	}
 }

substrate/primitives/npos-elections/src/mock.rs

@@ -19,12 +19,12 @@
 
 #![cfg(test)]
 
+use alloc::collections::btree_map::BTreeMap;
 use sp_arithmetic::{
 	traits::{One, SaturatedConversion, Zero},
 	PerThing,
 };
 use sp_runtime::assert_eq_error_rate;
-use sp_std::collections::btree_map::BTreeMap;
 
 use crate::{seq_phragmen, Assignment, ElectionResult, ExtendedBalance, PerThing128, VoteWeight};
 
@@ -131,7 +131,7 @@ where
 		if let Some(winner) = candidates
 			.iter_mut()
 			.filter(|c| !c.elected)
-			.min_by(|x, y| x.score.partial_cmp(&y.score).unwrap_or(sp_std::cmp::Ordering::Equal))
+			.min_by(|x, y| x.score.partial_cmp(&y.score).unwrap_or(core::cmp::Ordering::Equal))
 		{
 			winner.elected = true;
 			for n in &mut voters {
@@ -226,10 +226,10 @@ where
 	if backing_backed_stake.len() > 0 {
 		let max_stake = backing_backed_stake
 			.iter()
-			.max_by(|x, y| x.partial_cmp(&y).unwrap_or(sp_std::cmp::Ordering::Equal))
+			.max_by(|x, y| x.partial_cmp(&y).unwrap_or(core::cmp::Ordering::Equal))
 			.expect("vector with positive length will have a max; qed");
 		let min_stake = backed_stakes_iter
-			.min_by(|x, y| x.partial_cmp(&y).unwrap_or(sp_std::cmp::Ordering::Equal))
+			.min_by(|x, y| x.partial_cmp(&y).unwrap_or(core::cmp::Ordering::Equal))
 			.expect("iterator with positive length will have a min; qed");
 
 		difference = max_stake - min_stake;
@@ -254,7 +254,7 @@ where
 		support_map
 			.get(&x.0)
 			.and_then(|x| support_map.get(&y.0).and_then(|y| x.total.partial_cmp(&y.total)))
-			.unwrap_or(sp_std::cmp::Ordering::Equal)
+			.unwrap_or(core::cmp::Ordering::Equal)
 	});
 
 	let mut cumulative_stake = 0.0;

substrate/primitives/npos-elections/src/node.rs

@@ -17,7 +17,8 @@
 
 //! (very) Basic implementation of a graph node used in the reduce algorithm.
 
-use sp_std::{cell::RefCell, fmt, prelude::*, rc::Rc};
+use alloc::{rc::Rc, vec::Vec};
+use core::{cell::RefCell, fmt};
 
 /// The role that a node can accept.
 #[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Debug)]
@@ -49,8 +50,8 @@ impl<A> NodeId<A> {
 }
 
 #[cfg(feature = "std")]
-impl<A: fmt::Debug> sp_std::fmt::Debug for NodeId<A> {
-	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> sp_std::fmt::Result {
+impl<A: fmt::Debug> fmt::Debug for NodeId<A> {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 		write!(
 			f,
 			"Node({:?}, {:?})",

substrate/primitives/npos-elections/src/phragmen.rs

@@ -24,12 +24,12 @@ use crate::{
 	balancing, setup_inputs, BalancingConfig, CandidatePtr, ElectionResult, ExtendedBalance,
 	IdentifierT, PerThing128, VoteWeight, Voter,
 };
+use alloc::vec::Vec;
 use sp_arithmetic::{
 	helpers_128bit::multiply_by_rational_with_rounding,
 	traits::{Bounded, Zero},
 	Rational128, Rounding,
 };
-use sp_std::prelude::*;
 
 /// The denominator used for loads. Since votes are collected as u64, the smallest ratio that we
 /// might collect is `1/approval_stake` where approval stake is the sum of votes. Hence, some number

substrate/primitives/npos-elections/src/phragmms.rs

@@ -25,8 +25,8 @@ use crate::{
 	balance, setup_inputs, BalancingConfig, CandidatePtr, ElectionResult, ExtendedBalance,
 	IdentifierT, PerThing128, VoteWeight, Voter,
 };
+use alloc::{rc::Rc, vec, vec::Vec};
 use sp_arithmetic::{traits::Bounded, PerThing, Rational128};
-use sp_std::{prelude::*, rc::Rc};
 
 /// Execute the phragmms method.
 ///
@@ -232,8 +232,8 @@ pub(crate) fn apply_elected<AccountId: IdentifierT>(
 mod tests {
 	use super::*;
 	use crate::{Assignment, ElectionResult};
+	use alloc::rc::Rc;
 	use sp_runtime::{Perbill, Percent};
-	use sp_std::rc::Rc;
 
 	#[test]
 	fn basic_election_manual_works() {

substrate/primitives/npos-elections/src/pjr.rs

@@ -26,8 +26,8 @@ use crate::{
 	Candidate, CandidatePtr, Edge, ExtendedBalance, IdentifierT, Support, SupportMap, Supports,
 	VoteWeight, Voter,
 };
+use alloc::{collections::btree_map::BTreeMap, rc::Rc, vec::Vec};
 use sp_arithmetic::{traits::Zero, Perbill};
-use sp_std::{collections::btree_map::BTreeMap, rc::Rc, vec::Vec};
 /// The type used as the threshold.
 ///
 /// Just some reading sugar; Must always be same as [`ExtendedBalance`];

substrate/primitives/npos-elections/src/reduce.rs

@@ -51,11 +51,12 @@ use crate::{
 	node::{Node, NodeId, NodeRef, NodeRole},
 	ExtendedBalance, IdentifierT, StakedAssignment,
 };
-use sp_arithmetic::traits::{Bounded, Zero};
-use sp_std::{
+use alloc::{
 	collections::btree_map::{BTreeMap, Entry::*},
-	prelude::*,
+	vec,
+	vec::Vec,
 };
+use sp_arithmetic::traits::{Bounded, Zero};
 
 /// Map type used for reduce_4. Can be easily swapped with HashMap.
 type Map<A> = BTreeMap<(A, A), A>;

substrate/primitives/npos-elections/src/traits.rs

@@ -18,8 +18,8 @@
 //! Traits for the npos-election operations.
 
 use crate::ExtendedBalance;
+use core::{fmt::Debug, ops::Mul};
 use sp_arithmetic::PerThing;
-use sp_std::{fmt::Debug, ops::Mul, prelude::*};
 
 /// an aggregator trait for a generic type of a voter/target identifier. This usually maps to
 /// substrate's account id.