Relaxed clippy fixes/nits (#2661)

This PR contains just a few clippy fixes and nits, which are, however,
relaxed by workspace clippy settings here:
https://github.com/paritytech/polkadot-sdk/blob/master/Cargo.toml#L483-L506

---------

Co-authored-by: Dmitry Sinyavin <dmitry.sinyavin@parity.io>
Co-authored-by: ordian <write@reusable.software>
Co-authored-by: command-bot <>
Co-authored-by: Bastian Köcher <git@kchr.de>

substrate/client/chain-spec/src/genesis_config_builder.rs

@@ -141,7 +141,7 @@ where
 mod tests {
 	use super::*;
 	use serde_json::{from_str, json};
-	pub use sp_consensus_babe::{AllowedSlots, BabeEpochConfiguration, Slot};
+	pub use sp_consensus_babe::{AllowedSlots, BabeEpochConfiguration};
 
 	#[test]
 	fn get_default_config_works() {

substrate/frame/alliance/src/mock.rs

@@ -19,16 +19,12 @@
 
 pub use sp_core::H256;
 use sp_runtime::traits::Hash;
-pub use sp_runtime::{
-	traits::{BlakeTwo256, IdentityLookup},
-	BuildStorage,
-};
+pub use sp_runtime::{traits::BlakeTwo256, BuildStorage};
 use sp_std::convert::{TryFrom, TryInto};
 
 pub use frame_support::{
 	assert_noop, assert_ok, derive_impl, ord_parameter_types, parameter_types,
-	traits::{EitherOfDiverse, SortedMembers},
-	BoundedVec,
+	traits::EitherOfDiverse, BoundedVec,
 };
 use frame_system::{EnsureRoot, EnsureSignedBy};
 use pallet_identity::{

substrate/frame/assets/src/benchmarking.rs

@@ -102,7 +102,7 @@ fn add_sufficients<T: Config<I>, I: 'static>(minter: T::AccountId, n: u32) {
 
 fn add_approvals<T: Config<I>, I: 'static>(minter: T::AccountId, n: u32) {
 	let asset_id = default_asset_id::<T, I>();
-	T::Currency::deposit_creating(
+	let _ = T::Currency::deposit_creating(
 		&minter,
 		T::ApprovalDeposit::get() * n.into() + T::Currency::minimum_balance(),
 	);

substrate/frame/beefy/src/mock.rs

@@ -37,10 +37,7 @@ use sp_state_machine::BasicExternalities;
 
 use crate as pallet_beefy;
 
-pub use sp_consensus_beefy::{
-	ecdsa_crypto::{AuthorityId as BeefyId, AuthoritySignature as BeefySignature},
-	ConsensusLog, EquivocationProof, BEEFY_ENGINE_ID,
-};
+pub use sp_consensus_beefy::{ecdsa_crypto::AuthorityId as BeefyId, ConsensusLog, BEEFY_ENGINE_ID};
 
 impl_opaque_keys! {
 	pub struct MockSessionKeys {

substrate/frame/broker/src/lib.rs

@@ -42,9 +42,7 @@ pub use weights::WeightInfo;
 pub use adapt_price::*;
 pub use core_mask::*;
 pub use coretime_interface::*;
-pub use nonfungible_impl::*;
 pub use types::*;
-pub use utility_impls::*;
 
 #[frame_support::pallet]
 pub mod pallet {

substrate/frame/contracts/src/migration/v10.rs

@@ -219,7 +219,7 @@ where
 					"Failed to transfer the base deposit, reason: {:?}",
 					err
 				);
-				OldCurrency::deposit_creating(&deposit_account, min_balance);
+				let _ = OldCurrency::deposit_creating(&deposit_account, min_balance);
 				min_balance
 			});
 

substrate/frame/contracts/src/wasm/mod.rs

@@ -25,13 +25,15 @@ mod runtime;
 pub use crate::wasm::runtime::api_doc;
 
 pub use crate::wasm::runtime::{
-	AllowDeprecatedInterface, AllowUnstableInterface, Environment, ReturnErrorCode, Runtime,
-	RuntimeCosts,
+	AllowDeprecatedInterface, AllowUnstableInterface, Environment, Runtime, RuntimeCosts,
 };
-pub use pallet_contracts_uapi::ReturnFlags;
+
 #[cfg(test)]
 pub use tests::MockExt;
 
+#[cfg(test)]
+pub use crate::wasm::runtime::ReturnErrorCode;
+
 use crate::{
 	exec::{ExecResult, Executable, ExportedFunction, Ext},
 	gas::{GasMeter, Token},

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

@@ -21,7 +21,7 @@ use frame_election_provider_support::{
 	bounds::{DataProviderBounds, ElectionBounds},
 	data_provider, onchain, ElectionDataProvider, NposSolution, SequentialPhragmen,
 };
-pub use frame_support::{assert_noop, assert_ok, derive_impl, pallet_prelude::GetDefault};
+pub use frame_support::derive_impl;
 use frame_support::{
 	parameter_types,
 	traits::{ConstU32, Hooks},
@@ -117,7 +117,7 @@ pub fn roll_to_round(n: u32) {
 
 	while MultiPhase::round() != n {
 		roll_to_signed();
-		assert_ok!(MultiPhase::elect());
+		frame_support::assert_ok!(MultiPhase::elect());
 	}
 }
 
@@ -638,9 +638,9 @@ impl ExtBuilder {
 
 		#[cfg(feature = "try-runtime")]
 		ext.execute_with(|| {
-			assert_ok!(<MultiPhase as frame_support::traits::Hooks<u64>>::try_state(
-				System::block_number()
-			));
+			frame_support::assert_ok!(
+				<MultiPhase as frame_support::traits::Hooks<u64>>::try_state(System::block_number())
+			);
 		});
 	}
 }

substrate/frame/elections-phragmen/src/benchmarking.rs

@@ -38,7 +38,7 @@ fn endowed_account<T: Config>(name: &'static str, index: u32) -> T::AccountId {
 	let _ = T::Currency::make_free_balance_be(&account, amount);
 	// important to increase the total issuance since T::CurrencyToVote will need it to be sane for
 	// phragmen to work.
-	T::Currency::issue(amount);
+	let _ = T::Currency::issue(amount);
 
 	account
 }

substrate/frame/fast-unstake/src/lib.rs

@@ -571,7 +571,7 @@ pub mod pallet {
 					.any(|e| T::Staking::is_exposed_in_era(&stash, e));
 
 				if is_exposed {
-					T::Currency::slash_reserved(&stash, deposit);
+					let _ = T::Currency::slash_reserved(&stash, deposit);
 					log!(info, "slashed {:?} by {:?}", stash, deposit);
 					Self::deposit_event(Event::<T>::Slashed { stash, amount: deposit });
 					false

substrate/frame/indices/src/lib.rs

@@ -223,7 +223,7 @@ pub mod pallet {
 				let (account, amount, perm) = maybe_value.take().ok_or(Error::<T>::NotAssigned)?;
 				ensure!(!perm, Error::<T>::Permanent);
 				ensure!(account == who, Error::<T>::NotOwner);
-				T::Currency::slash_reserved(&who, amount);
+				let _ = T::Currency::slash_reserved(&who, amount);
 				*maybe_value = Some((account, Zero::zero(), true));
 				Ok(())
 			})?;

substrate/frame/lottery/src/lib.rs

@@ -368,7 +368,8 @@ pub mod pallet {
 			// Make sure pot exists.
 			let lottery_account = Self::account_id();
 			if T::Currency::total_balance(&lottery_account).is_zero() {
-				T::Currency::deposit_creating(&lottery_account, T::Currency::minimum_balance());
+				let _ =
+					T::Currency::deposit_creating(&lottery_account, T::Currency::minimum_balance());
 			}
 			Self::deposit_event(Event::<T>::LotteryStarted);
 			Ok(())

substrate/frame/paged-list/src/paged_list.rs

@@ -407,13 +407,11 @@ where
 #[allow(dead_code)]
 pub(crate) mod mock {
 	pub use super::*;
-	pub use frame_support::{
-		parameter_types,
-		storage::{types::ValueQuery, StorageList as _},
-		StorageNoopGuard,
-	};
-	pub use sp_io::{hashing::twox_128, TestExternalities};
-	pub use sp_metadata_ir::{StorageEntryModifierIR, StorageEntryTypeIR, StorageHasherIR};
+	pub use frame_support::parameter_types;
+	#[cfg(test)]
+	pub use frame_support::{storage::StorageList as _, StorageNoopGuard};
+	#[cfg(test)]
+	pub use sp_io::TestExternalities;
 
 	parameter_types! {
 		pub const ValuesPerNewPage: u32 = 5;

substrate/frame/staking/src/benchmarking.rs

@@ -250,7 +250,7 @@ benchmarks! {
 		let original_bonded: BalanceOf<T>
 			= Ledger::<T>::get(&controller).map(|l| l.active).ok_or("ledger not created after")?;
 
-		T::Currency::deposit_into_existing(&stash, max_additional).unwrap();
+		let _ = T::Currency::deposit_into_existing(&stash, max_additional).unwrap();
 
 		whitelist_account!(stash);
 	}: _(RawOrigin::Signed(stash), max_additional)

substrate/frame/support/src/dispatch.rs

@@ -664,7 +664,7 @@ mod weight_tests {
 	use sp_runtime::{generic, traits::BlakeTwo256};
 	use sp_weights::RuntimeDbWeight;
 
-	pub use self::frame_system::{Call, Config, Pallet};
+	pub use self::frame_system::{Call, Config};
 
 	fn from_actual_ref_time(ref_time: Option<u64>) -> PostDispatchInfo {
 		PostDispatchInfo {

substrate/primitives/database/src/lib.rs

@@ -101,7 +101,9 @@ pub trait Database<H: Clone + AsRef<[u8]>>: Send + Sync {
 	/// This may be faster than `get` since it doesn't allocate.
 	/// Use `with_get` helper function if you need `f` to return a value from `f`
 	fn with_get(&self, col: ColumnId, key: &[u8], f: &mut dyn FnMut(&[u8])) {
-		self.get(col, key).map(|v| f(&v));
+		if let Some(v) = self.get(col, key) {
+			f(&v)
+		}
 	}
 
 	/// Check if database supports internal ref counting for state data.

substrate/primitives/runtime-interface/proc-macro/src/utils.rs

@@ -89,7 +89,7 @@ struct RuntimeInterfaceFunctionSet {
 impl RuntimeInterfaceFunctionSet {
 	fn new(version: VersionAttribute, trait_item: &TraitItemFn) -> Result<Self> {
 		Ok(Self {
-			latest_version_to_call: version.is_callable().then(|| version.version),
+			latest_version_to_call: version.is_callable().then_some(version.version),
 			versions: BTreeMap::from([(
 				version.version,
 				RuntimeInterfaceFunction::new(trait_item)?,

substrate/primitives/storage/src/lib.rs

@@ -414,12 +414,13 @@ impl ChildTrieParentKeyId {
 ///
 /// V0 and V1 uses a same trie implementation, but V1 will write external value node in the trie for
 /// value with size at least `TRIE_VALUE_NODE_THRESHOLD`.
-#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+#[derive(Debug, Default, Clone, Copy, Eq, PartialEq)]
 #[cfg_attr(feature = "std", derive(Encode, Decode))]
 pub enum StateVersion {
 	/// Old state version, no value nodes.
 	V0 = 0,
 	/// New state version can use value nodes.
+	#[default]
 	V1 = 1,
 }
 
@@ -432,12 +433,6 @@ impl Display for StateVersion {
 	}
 }
 
-impl Default for StateVersion {
-	fn default() -> Self {
-		StateVersion::V1
-	}
-}
-
 impl From<StateVersion> for u8 {
 	fn from(version: StateVersion) -> u8 {
 		version as u8

substrate/utils/build-script-utils/src/git.rs

@@ -15,7 +15,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::{env, fs, fs::File, io, io::Read, path::PathBuf};
+use std::{
+	env, fs,
+	fs::File,
+	io,
+	io::Read,
+	path::{Path, PathBuf},
+};
 
 /// Make sure the calling `build.rs` script is rerun when `.git/HEAD` or the ref of `.git/HEAD`
 /// changed.
@@ -55,7 +61,7 @@ pub fn rerun_if_git_head_changed() {
 }
 
 // Code taken from https://github.com/rustyhorde/vergen/blob/8d522db8c8e16e26c0fc9ea8e6b0247cbf5cca84/src/output/envvar.rs
-fn get_git_paths(path: &PathBuf) -> Result<Option<Vec<PathBuf>>, io::Error> {
+fn get_git_paths(path: &Path) -> Result<Option<Vec<PathBuf>>, io::Error> {
 	let git_dir_or_file = path.join(".git");
 
 	if let Ok(metadata) = fs::metadata(&git_dir_or_file) {

substrate/utils/build-script-utils/src/version.rs

@@ -25,7 +25,7 @@ pub fn generate_cargo_keys() {
 		// We deliberately set the length here to `11` to ensure that
 		// the emitted hash is always of the same length; otherwise
 		// it can (and will!) vary between different build environments.
-		match Command::new("git").args(&["rev-parse", "--short=11", "HEAD"]).output() {
+		match Command::new("git").args(["rev-parse", "--short=11", "HEAD"]).output() {
 			Ok(o) if o.status.success() => {
 				let sha = String::from_utf8_lossy(&o.stdout).trim().to_owned();
 				Cow::from(sha)