Replace error-chain for client error (#2231)

* WIP: convert client error

* Remove error_chain for client error

* Ignore tx-pool error deprecation warning

* Update Cargo.lock files

* Fix tests

* Increment impl_version

* Derive From impls, remove allow(missing_docs)

* Remove space

* Remove redundant into()s

* Blockchain Error source

* Bump impl version

substrate/core/client/Cargo.toml

@@ -5,7 +5,7 @@ authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
 [dependencies]
-error-chain = { version = "0.12", optional = true }
+derive_more = { version = "0.14.0", optional = true }
 fnv = { version = "1.0", optional = true }
 log = { version = "0.4", optional = true }
 parking_lot = { version = "0.7.1", optional = true }
@@ -44,7 +44,7 @@ std = [
 	"hash-db/std",
 	"consensus",
 	"parking_lot",
-	"error-chain",
+	"derive_more",
 	"fnv",
 	"log",
 	"hex",

substrate/core/client/db/src/cache/list_cache.rs

@@ -43,7 +43,7 @@ use std::collections::BTreeSet;
 
 use log::warn;
 
-use client::error::{ErrorKind as ClientErrorKind, Result as ClientResult};
+use client::error::{Error as ClientError, Result as ClientResult};
 use runtime_primitives::traits::{Block as BlockT, NumberFor, As, Zero};
 
 use crate::cache::{CacheItemT, ComplexBlockId};
@@ -537,10 +537,10 @@ mod chain {
 	) -> ClientResult<bool> {
 		let (begin, end) = if block1 > block2 { (block2, block1) } else { (block1, block2) };
 		let mut current = storage.read_header(&end.hash)?
-			.ok_or_else(|| ClientErrorKind::UnknownBlock(format!("{}", end.hash)))?;
+			.ok_or_else(|| ClientError::UnknownBlock(format!("{}", end.hash)))?;
 		while *current.number() > begin.number {
 			current = storage.read_header(current.parent_hash())?
-				.ok_or_else(|| ClientErrorKind::UnknownBlock(format!("{}", current.parent_hash())))?;
+				.ok_or_else(|| ClientError::UnknownBlock(format!("{}", current.parent_hash())))?;
 		}
 
 		Ok(begin.hash == current.hash())

substrate/core/client/db/src/cache/list_storage.rs

@@ -20,7 +20,7 @@ use std::sync::Arc;
 
 use kvdb::{KeyValueDB, DBTransaction};
 
-use client::error::{Error as ClientError, ErrorKind as ClientErrorKind, Result as ClientResult};
+use client::error::{Error as ClientError, Result as ClientResult};
 use parity_codec::{Encode, Decode};
 use runtime_primitives::generic::BlockId;
 use runtime_primitives::traits::{Block as BlockT, Header as HeaderT, NumberFor};
@@ -59,7 +59,7 @@ pub trait Storage<Block: BlockT, T: CacheItemT> {
 		self.read_entry(at)
 			.and_then(|entry| entry
 				.ok_or_else(|| ClientError::from(
-					ClientErrorKind::Backend(format!("Referenced cache entry at {:?} is not found", at)))))
+					ClientError::Backend(format!("Referenced cache entry at {:?} is not found", at)))))
 	}
 }
 
@@ -151,7 +151,7 @@ impl<Block: BlockT, T: CacheItemT> Storage<Block, T> for DbStorage {
 			.map_err(db_err)
 			.and_then(|entry| match entry {
 				Some(entry) => StorageEntry::<Block, T>::decode(&mut &entry[..])
-					.ok_or_else(|| ClientErrorKind::Backend("Failed to decode cache entry".into()).into())
+					.ok_or_else(|| ClientError::Backend("Failed to decode cache entry".into()))
 					.map(Some),
 				None => Ok(None),
 			})
@@ -236,9 +236,9 @@ mod meta {
 	pub fn decode<Block: BlockT>(encoded: &[u8]) -> ClientResult<Metadata<Block>> {
 		let input = &mut &*encoded;
 		let finalized: Option<ComplexBlockId<Block>> = Decode::decode(input)
-			.ok_or_else(|| ClientError::from(ClientErrorKind::Backend("Error decoding cache meta".into())))?;
+			.ok_or_else(|| ClientError::from(ClientError::Backend("Error decoding cache meta".into())))?;
 		let unfinalized: Vec<ComplexBlockId<Block>> = Decode::decode(input)
-			.ok_or_else(|| ClientError::from(ClientErrorKind::Backend("Error decoding cache meta".into())))?;
+			.ok_or_else(|| ClientError::from(ClientError::Backend("Error decoding cache meta".into())))?;
 
 		Ok(Metadata { finalized, unfinalized })
 	}
@@ -253,19 +253,19 @@ pub mod tests {
 
 	impl<Block: BlockT, T: CacheItemT> Storage<Block, T> for FaultyStorage {
 		fn read_id(&self, _at: NumberFor<Block>) -> ClientResult<Option<Block::Hash>> {
-			Err(ClientErrorKind::Backend("TestError".into()).into())
+			Err(ClientError::Backend("TestError".into()))
 		}
 
 		fn read_header(&self, _at: &Block::Hash) -> ClientResult<Option<Block::Header>> {
-			Err(ClientErrorKind::Backend("TestError".into()).into())
+			Err(ClientError::Backend("TestError".into()))
 		}
 
 		fn read_meta(&self) -> ClientResult<Metadata<Block>> {
-			Err(ClientErrorKind::Backend("TestError".into()).into())
+			Err(ClientError::Backend("TestError".into()))
 		}
 
 		fn read_entry(&self, _at: &ComplexBlockId<Block>) -> ClientResult<Option<StorageEntry<Block, T>>> {
-			Err(ClientErrorKind::Backend("TestError".into()).into())
+			Err(ClientError::Backend("TestError".into()))
 		}
 	}
 

substrate/core/client/db/src/lib.rs

@@ -225,7 +225,7 @@ impl<Block: BlockT> client::blockchain::Backend<Block> for BlockchainDb<Block> {
 		match read_db(&*self.db, columns::KEY_LOOKUP, columns::BODY, id)? {
 			Some(body) => match Decode::decode(&mut &body[..]) {
 				Some(body) => Ok(Some(body)),
-				None => return Err(client::error::ErrorKind::Backend("Error decoding body".into()).into()),
+				None => return Err(client::error::Error::Backend("Error decoding body".into())),
 			}
 			None => Ok(None),
 		}
@@ -235,7 +235,7 @@ impl<Block: BlockT> client::blockchain::Backend<Block> for BlockchainDb<Block> {
 		match read_db(&*self.db, columns::KEY_LOOKUP, columns::JUSTIFICATION, id)? {
 			Some(justification) => match Decode::decode(&mut &justification[..]) {
 				Some(justification) => Ok(Some(justification)),
-				None => return Err(client::error::ErrorKind::Backend("Error decoding justification".into()).into()),
+				None => return Err(client::error::Error::Backend("Error decoding justification".into())),
 			}
 			None => Ok(None),
 		}
@@ -326,14 +326,14 @@ where Block: BlockT<Hash=H256>,
 	fn reset_storage(&mut self, mut top: StorageOverlay, children: ChildrenStorageOverlay) -> Result<H256, client::error::Error> {
 
 		if top.iter().any(|(k, _)| well_known_keys::is_child_storage_key(k)) {
-			return Err(client::error::ErrorKind::GenesisInvalid.into());
+			return Err(client::error::Error::GenesisInvalid.into());
 		}
 
 		let mut transaction: PrefixedMemoryDB<Blake2Hasher> = Default::default();
 
 		for (child_key, child_map) in children {
 			if !well_known_keys::is_child_storage_key(&child_key) {
-				return Err(client::error::ErrorKind::GenesisInvalid.into());
+				return Err(client::error::Error::GenesisInvalid.into());
 			}
 
 			let (root, is_default, update) = self.old_state.child_storage_root(&child_key, child_map.into_iter().map(|(k, v)| (k, Some(v))));
@@ -684,7 +684,7 @@ impl<Block: BlockT<Hash=H256>> Backend<Block> {
 						(&r.number, &r.hash)
 					);
 
-					return Err(::client::error::ErrorKind::NotInFinalizedChain.into());
+					return Err(::client::error::Error::NotInFinalizedChain.into());
 				}
 
 				retracted.push(r.hash.clone());
@@ -726,7 +726,7 @@ impl<Block: BlockT<Hash=H256>> Backend<Block> {
 	) -> Result<(), client::error::Error> {
 		let last_finalized = last_finalized.unwrap_or_else(|| self.blockchain.meta.read().finalized_hash);
 		if *header.parent_hash() != last_finalized {
-			return Err(::client::error::ErrorKind::NonSequentialFinalization(
+			return Err(::client::error::Error::NonSequentialFinalization(
 				format!("Last finalized {:?} not parent of {:?}", last_finalized, header.hash()),
 			).into());
 		}
@@ -926,7 +926,7 @@ impl<Block: BlockT<Hash=H256>> Backend<Block> {
 					(number.clone(), hash.clone())
 				)?;
 			} else {
-				return Err(client::error::ErrorKind::UnknownBlock(format!("Cannot set head {:?}", set_head)).into())
+				return Err(client::error::Error::UnknownBlock(format!("Cannot set head {:?}", set_head)))
 			}
 		}
 
@@ -1138,12 +1138,12 @@ impl<Block> client::backend::Backend<Block, Blake2Hasher> for Backend<Block> whe
 				Some(commit) => {
 					apply_state_commit(&mut transaction, commit);
 					let removed = self.blockchain.header(BlockId::Number(best))?.ok_or_else(
-						|| client::error::ErrorKind::UnknownBlock(
+						|| client::error::Error::UnknownBlock(
 							format!("Error reverting to {}. Block hash not found.", best)))?;
 
 					best -= As::sa(1);  // prev block
 					let hash = self.blockchain.hash(best)?.ok_or_else(
-						|| client::error::ErrorKind::UnknownBlock(
+						|| client::error::Error::UnknownBlock(
 							format!("Error reverting to {}. Block hash not found.", best)))?;
 					let key = utils::number_and_hash_to_lookup_key(best.clone(), &hash);
 					transaction.put(columns::META, meta_keys::BEST_BLOCK, &key);
@@ -1185,10 +1185,10 @@ impl<Block> client::backend::Backend<Block, Blake2Hasher> for Backend<Block> whe
 					let state = DbState::new(self.storage.clone(), root);
 					Ok(CachingState::new(state, self.shared_cache.clone(), Some(hash)))
 				} else {
-					Err(client::error::ErrorKind::UnknownBlock(format!("State already discarded for {:?}", block)).into())
+					Err(client::error::Error::UnknownBlock(format!("State already discarded for {:?}", block)))
 				}
 			},
-			Ok(None) => Err(client::error::ErrorKind::UnknownBlock(format!("Unknown state for block {:?}", block)).into()),
+			Ok(None) => Err(client::error::Error::UnknownBlock(format!("Unknown state for block {:?}", block))),
 			Err(e) => Err(e),
 		}
 	}

substrate/core/client/db/src/light.rs

@@ -26,7 +26,7 @@ use client::blockchain::{BlockStatus, Cache as BlockchainCache,
 	HeaderBackend as BlockchainHeaderBackend, Info as BlockchainInfo};
 use client::cht;
 use client::leaves::{LeafSet, FinalizationDisplaced};
-use client::error::{ErrorKind as ClientErrorKind, Result as ClientResult};
+use client::error::{Error as ClientError, Result as ClientResult};
 use client::light::blockchain::Storage as LightBlockchainStorage;
 use parity_codec::{Decode, Encode};
 use primitives::Blake2Hasher;
@@ -256,7 +256,7 @@ impl<Block: BlockT> LightStorage<Block> {
 	) -> ClientResult<()> {
 		let meta = self.meta.read();
 		if &meta.finalized_hash != header.parent_hash() {
-			return Err(::client::error::ErrorKind::NonSequentialFinalization(
+			return Err(::client::error::Error::NonSequentialFinalization(
 				format!("Last finalized {:?} not parent of {:?}",
 					meta.finalized_hash, hash),
 			).into())
@@ -330,7 +330,7 @@ impl<Block: BlockT> LightStorage<Block> {
 		cht_size: u64,
 		block: NumberFor<Block>
 	) -> ClientResult<Block::Hash> {
-		let no_cht_for_block = || ClientErrorKind::Backend(format!("CHT for block {} not exists", block)).into();
+		let no_cht_for_block = || ClientError::Backend(format!("CHT for block {} not exists", block));
 
 		let cht_number = cht::block_to_cht_number(cht_size, block).ok_or_else(no_cht_for_block)?;
 		let cht_start = cht::start_number(cht_size, cht_number);
@@ -474,7 +474,7 @@ impl<Block> LightBlockchainStorage<Block> for LightStorage<Block>
 			self.db.write(transaction).map_err(db_err)?;
 			Ok(())
 		} else {
-			Err(ClientErrorKind::UnknownBlock(format!("Cannot set head {:?}", id)).into())
+			Err(ClientError::UnknownBlock(format!("Cannot set head {:?}", id)))
 		}
 	}
 
@@ -514,7 +514,7 @@ impl<Block> LightBlockchainStorage<Block> for LightStorage<Block>
 
 			Ok(())
 		} else {
-			Err(ClientErrorKind::UnknownBlock(format!("Cannot finalize block {:?}", id)).into())
+			Err(ClientError::UnknownBlock(format!("Cannot finalize block {:?}", id)))
 		}
 	}
 

substrate/core/client/db/src/utils.rs

@@ -105,7 +105,7 @@ pub fn number_and_hash_to_lookup_key<N, H>(number: N, hash: H) -> Vec<u8> where
 /// all block lookup keys start with the block number.
 pub fn lookup_key_to_number<N>(key: &[u8]) -> client::error::Result<N> where N: As<u64> {
 	if key.len() < 4 {
-		return Err(client::error::ErrorKind::Backend("Invalid block key".into()).into());
+		return Err(client::error::Error::Backend("Invalid block key".into()));
 	}
 	Ok((key[0] as u64) << 24
 		| (key[1] as u64) << 16
@@ -187,21 +187,21 @@ pub fn block_id_to_lookup_key<Block>(
 /// Maps database error to client error
 pub fn db_err(err: io::Error) -> client::error::Error {
 	use std::error::Error;
-	client::error::ErrorKind::Backend(err.description().into()).into()
+	client::error::Error::Backend(err.description().into())
 }
 
 /// Open RocksDB database.
 pub fn open_database(config: &DatabaseSettings, col_meta: Option<u32>, db_type: &str) -> client::error::Result<Arc<KeyValueDB>> {
 	let mut db_config = DatabaseConfig::with_columns(Some(NUM_COLUMNS));
 	db_config.memory_budget = config.cache_size;
-	let path = config.path.to_str().ok_or_else(|| client::error::ErrorKind::Backend("Invalid database path".into()))?;
+	let path = config.path.to_str().ok_or_else(|| client::error::Error::Backend("Invalid database path".into()))?;
 	let db = Database::open(&db_config, &path).map_err(db_err)?;
 
 	// check database type
 	match db.get(col_meta, meta_keys::TYPE).map_err(db_err)? {
 		Some(stored_type) => {
 			if db_type.as_bytes() != &*stored_type {
-				return Err(client::error::ErrorKind::Backend(
+				return Err(client::error::Error::Backend(
 					format!("Unexpected database type. Expected: {}", db_type)).into());
 			}
 		},
@@ -237,7 +237,7 @@ pub fn read_header<Block: BlockT>(
 		Some(header) => match Block::Header::decode(&mut &header[..]) {
 			Some(header) => Ok(Some(header)),
 			None => return Err(
-				client::error::ErrorKind::Backend("Error decoding header".into()).into()
+				client::error::Error::Backend("Error decoding header".into())
 			),
 		}
 		None => Ok(None),
@@ -252,7 +252,7 @@ pub fn require_header<Block: BlockT>(
 	id: BlockId<Block>,
 ) -> client::error::Result<Block::Header> {
 	read_header(db, col_index, col, id)
-		.and_then(|header| header.ok_or_else(|| client::error::ErrorKind::UnknownBlock(format!("{}", id)).into()))
+		.and_then(|header| header.ok_or_else(|| client::error::Error::UnknownBlock(format!("{}", id))))
 }
 
 /// Read meta from the database.
@@ -266,7 +266,7 @@ pub fn read_meta<Block>(db: &KeyValueDB, col_meta: Option<u32>, col_header: Opti
 	let genesis_hash: Block::Hash = match db.get(col_meta, meta_keys::GENESIS_HASH).map_err(db_err)? {
 		Some(h) => match Decode::decode(&mut &h[..]) {
 			Some(h) => h,
-			None => return Err(client::error::ErrorKind::Backend("Error decoding genesis hash".into()).into()),
+			None => return Err(client::error::Error::Backend("Error decoding genesis hash".into())),
 		},
 		None => return Ok(Meta {
 			best_hash: Default::default(),

substrate/core/client/src/block_builder/block_builder.rs

@@ -51,11 +51,11 @@ where
 	/// build upon.
 	pub fn at_block(block_id: &BlockId<Block>, api: &'a A) -> error::Result<Self> {
 		let number = api.block_number_from_id(block_id)?
-			.ok_or_else(|| error::ErrorKind::UnknownBlock(format!("{}", block_id)))?
+			.ok_or_else(|| error::Error::UnknownBlock(format!("{}", block_id)))?
 			+ One::one();
 
 		let parent_hash = api.block_hash_from_id(block_id)?
-			.ok_or_else(|| error::ErrorKind::UnknownBlock(format!("{}", block_id)))?;
+			.ok_or_else(|| error::Error::UnknownBlock(format!("{}", block_id)))?;
 		let header = <<Block as BlockT>::Header as HeaderT>::new(
 			number,
 			Default::default(),
@@ -89,7 +89,7 @@ where
 					Ok(())
 				}
 				Err(e) => {
-					Err(error::ErrorKind::ApplyExtrinsicFailed(e).into())
+					Err(error::Error::ApplyExtrinsicFailed(e))
 				}
 			}
 		})

substrate/core/client/src/blockchain.rs

@@ -23,7 +23,7 @@ use runtime_primitives::generic::BlockId;
 use runtime_primitives::Justification;
 use consensus::well_known_cache_keys;
 
-use crate::error::{ErrorKind, Result};
+use crate::error::{Error, Result};
 
 /// Blockchain database header backend. Does not perform any validation.
 pub trait HeaderBackend<Block: BlockT>: Send + Sync {
@@ -56,19 +56,19 @@ pub trait HeaderBackend<Block: BlockT>: Send + Sync {
 
 	/// Get block header. Returns `UnknownBlock` error if block is not found.
 	fn expect_header(&self, id: BlockId<Block>) -> Result<Block::Header> {
-		self.header(id)?.ok_or_else(|| ErrorKind::UnknownBlock(format!("{}", id)).into())
+		self.header(id)?.ok_or_else(|| Error::UnknownBlock(format!("{}", id)))
 	}
 
 	/// Convert an arbitrary block ID into a block number. Returns `UnknownBlock` error if block is not found.
 	fn expect_block_number_from_id(&self, id: &BlockId<Block>) -> Result<NumberFor<Block>> {
 		self.block_number_from_id(id)
-			.and_then(|n| n.ok_or_else(|| ErrorKind::UnknownBlock(format!("{}", id)).into()))
+			.and_then(|n| n.ok_or_else(|| Error::UnknownBlock(format!("{}", id))))
 	}
 
 	/// Convert an arbitrary block ID into a block hash. Returns `UnknownBlock` error if block is not found.
 	fn expect_block_hash_from_id(&self, id: &BlockId<Block>) -> Result<Block::Hash> {
 		self.block_hash_from_id(id)
-			.and_then(|n| n.ok_or_else(|| ErrorKind::UnknownBlock(format!("{}", id)).into()))
+			.and_then(|n| n.ok_or_else(|| Error::UnknownBlock(format!("{}", id))))
 	}
 }
 
@@ -196,7 +196,7 @@ pub fn tree_route<Block: BlockT, Backend: HeaderBackend<Block>>(
 	let load_header = |id: BlockId<Block>| {
 		match backend.header(id) {
 			Ok(Some(hdr)) => Ok(hdr),
-			Ok(None) => Err(ErrorKind::UnknownBlock(format!("Unknown block {:?}", id)).into()),
+			Ok(None) => Err(Error::UnknownBlock(format!("Unknown block {:?}", id))),
 			Err(e) => Err(e),
 		}
 	};

substrate/core/client/src/call_executor.rs

@@ -274,7 +274,7 @@ where
 		let mut overlay = OverlayedChanges::default();
 		let state = self.backend.state_at(*id)?;
 		let mut ext = Ext::new(&mut overlay, &state, self.backend.changes_trie_storage(), NeverOffchainExt::new());
-		self.executor.runtime_version(&mut ext).ok_or(error::ErrorKind::VersionInvalid.into())
+		self.executor.runtime_version(&mut ext).ok_or(error::Error::VersionInvalid.into())
 	}
 
 	fn call_at_state<

substrate/core/client/src/children.rs

@@ -32,7 +32,7 @@ pub fn read_children<
 
 	let raw_val_opt = match db.get(column, &buf[..]) {
 		Ok(raw_val_opt) => raw_val_opt,
-		Err(_) => return Err(error::ErrorKind::Backend("Error reading value from database".into()).into()),
+		Err(_) => return Err(error::Error::Backend("Error reading value from database".into())),
 	};
 
 	let raw_val = match raw_val_opt {
@@ -42,7 +42,7 @@ pub fn read_children<
 
 	let children: Vec<V> = match Decode::decode(&mut &raw_val[..]) {
 		Some(children) => children,
-		None => return Err(error::ErrorKind::Backend("Error decoding children".into()).into()),
+		None => return Err(error::Error::Backend("Error decoding children".into())),
 	};
 
 	Ok(children)
@@ -118,4 +118,4 @@ mod tests {
 		assert_eq!(r1, vec![1_3, 1_5]);
 		assert_eq!(r2.len(), 0);		
 	}
-}
+}

substrate/core/client/src/cht.rs

@@ -35,7 +35,7 @@ use state_machine::backend::InMemory as InMemoryState;
 use state_machine::{MemoryDB, TrieBackend, Backend as StateBackend,
 	prove_read_on_trie_backend, read_proof_check, read_proof_check_on_proving_backend};
 
-use crate::error::{Error as ClientError, ErrorKind as ClientErrorKind, Result as ClientResult};
+use crate::error::{Error as ClientError, Result as ClientResult};
 
 /// The size of each CHT. This value is passed to every CHT-related function from
 /// production code. Other values are passed from tests.
@@ -160,11 +160,11 @@ fn do_check_proof<Header, Hasher, F>(
 	let root: Hasher::Out = convert_hash(&local_root);
 	let local_cht_key = encode_cht_key(local_number);
 	let local_cht_value = checker(root, &local_cht_key)?;
-	let local_cht_value = local_cht_value.ok_or_else(|| ClientErrorKind::InvalidCHTProof)?;
-	let local_hash = decode_cht_value(&local_cht_value).ok_or_else(|| ClientErrorKind::InvalidCHTProof)?;
+	let local_cht_value = local_cht_value.ok_or_else(|| ClientError::InvalidCHTProof)?;
+	let local_hash = decode_cht_value(&local_cht_value).ok_or_else(|| ClientError::InvalidCHTProof)?;
 	match &local_hash[..] == remote_hash.as_ref() {
 		true => Ok(()),
-		false => Err(ClientErrorKind::InvalidCHTProof.into()),
+		false => Err(ClientError::InvalidCHTProof.into()),
 	}
 
 }
@@ -186,7 +186,7 @@ pub fn for_each_cht_group<Header, I, F, P>(
 	for block in blocks {
 		let new_cht_num = match block_to_cht_number(cht_size, block.as_()) {
 			Some(new_cht_num) => new_cht_num,
-			None => return Err(ClientErrorKind::Backend(format!(
+			None => return Err(ClientError::Backend(format!(
 				"Cannot compute CHT root for the block #{}", block)).into()
 			),
 		};
@@ -234,7 +234,7 @@ fn build_pairs<Header, I>(
 	let mut hash_number = start_num;
 	for hash in hashes.into_iter().take(cht_size as usize) {
 		let hash = hash?.ok_or_else(|| ClientError::from(
-			ClientErrorKind::MissingHashRequiredForCHT(cht_num.as_(), hash_number.as_())
+			ClientError::MissingHashRequiredForCHT(cht_num.as_(), hash_number.as_())
 		))?;
 		pairs.push((
 			encode_cht_key(hash_number).to_vec(),
@@ -246,7 +246,7 @@ fn build_pairs<Header, I>(
 	if pairs.len() as u64 == cht_size {
 		Ok(pairs)
 	} else {
-		Err(ClientErrorKind::MissingHashRequiredForCHT(cht_num.as_(), hash_number.as_()).into())
+		Err(ClientError::MissingHashRequiredForCHT(cht_num.as_(), hash_number.as_()))
 	}
 }
 

substrate/core/client/src/client.rs

@@ -57,7 +57,7 @@ use executor::{RuntimeVersion, RuntimeInfo};
 use crate::notifications::{StorageNotifications, StorageEventStream};
 use crate::light::{call_executor::prove_execution, fetcher::ChangesProof};
 use crate::cht;
-use crate::error::{self, ErrorKind};
+use crate::error;
 use crate::in_mem;
 use crate::block_builder::{self, api::BlockBuilder as BlockBuilderAPI};
 use crate::genesis;
@@ -65,7 +65,6 @@ use consensus;
 use substrate_telemetry::{telemetry, SUBSTRATE_INFO};
 
 use log::{info, trace, warn};
-use error_chain::bail;
 
 /// Type that implements `futures::Stream` of block import events.
 pub type ImportNotifications<Block> = mpsc::UnboundedReceiver<BlockImportNotification<Block>>;
@@ -383,7 +382,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 
 	/// Reads given header and generates CHT-based header proof for CHT of given size.
 	pub fn header_proof_with_cht_size(&self, id: &BlockId<Block>, cht_size: u64) -> error::Result<(Block::Header, Vec<Vec<u8>>)> {
-		let proof_error = || error::ErrorKind::Backend(format!("Failed to generate header proof for {:?}", id));
+		let proof_error = || error::Error::Backend(format!("Failed to generate header proof for {:?}", id));
 		let header = self.backend.blockchain().expect_header(*id)?;
 		let block_num = *header.number();
 		let cht_num = cht::block_to_cht_number(cht_size, block_num).ok_or_else(proof_error)?;
@@ -409,7 +408,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
  		let first = first.as_();
 		let last_num = self.backend.blockchain().expect_block_number_from_id(&last)?.as_();
 		if first > last_num {
-			return Err(error::ErrorKind::ChangesTrieAccessFailed("Invalid changes trie range".into()).into());
+			return Err(error::Error::ChangesTrieAccessFailed("Invalid changes trie range".into()));
 		}
  		let finalized_number = self.backend.blockchain().info()?.finalized_number;
 		let oldest = storage.oldest_changes_trie_block(&config, finalized_number.as_());
@@ -440,7 +439,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 			self.backend.blockchain().info()?.best_number.as_(),
 			&key.0)
 		.and_then(|r| r.map(|r| r.map(|(block, tx)| (As::sa(block), tx))).collect::<Result<_, _>>())
-		.map_err(|err| error::ErrorKind::ChangesTrieAccessFailed(err).into())
+		.map_err(|err| error::Error::ChangesTrieAccessFailed(err))
 	}
 
 	/// Get proof for computation of (block, extrinsic) pairs where key has been changed at given blocks range.
@@ -532,7 +531,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 			max_number.as_(),
 			&key.0
 		)
-		.map_err(|err| error::Error::from(error::ErrorKind::ChangesTrieAccessFailed(err)))?;
+		.map_err(|err| error::Error::from(error::Error::ChangesTrieAccessFailed(err)))?;
 
 		// now gather proofs for all changes tries roots that were touched during key_changes_proof
 		// execution AND are unknown (i.e. replaced with CHT) to the requester
@@ -586,7 +585,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		let storage = self.backend.changes_trie_storage();
 		match (config, storage) {
 			(Some(config), Some(storage)) => Ok((config, storage)),
-			_ => Err(error::ErrorKind::ChangesTriesNotSupported.into()),
+			_ => Err(error::Error::ChangesTriesNotSupported.into()),
 		}
 	}
 
@@ -910,7 +909,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 			warn!("Safety violation: attempted to revert finalized block {:?} which is not in the \
 				same chain as last finalized {:?}", retracted, last_finalized);
 
-			bail!(error::ErrorKind::NotInFinalizedChain);
+			return Err(error::Error::NotInFinalizedChain);
 		}
 
 		let route_from_best = crate::blockchain::tree_route(
@@ -1241,7 +1240,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		let load_header = |id: Block::Hash| -> error::Result<Block::Header> {
 			match self.backend.blockchain().header(BlockId::Hash(id))? {
 				Some(hdr) => Ok(hdr),
-				None => Err(ErrorKind::UnknownBlock(format!("Unknown block {:?}", id)).into()),
+				None => Err(Error::UnknownBlock(format!("Unknown block {:?}", id))),
 			}
 		};
 

substrate/core/client/src/error.rs

@@ -16,159 +16,117 @@
 
 //! Substrate client possible errors.
 
-// Silence: `use of deprecated item 'std::error::Error::cause': replaced by Error::source, which can support downcasting`
-// https://github.com/paritytech/substrate/issues/1547
-#![allow(deprecated)]
-#![allow(missing_docs)]
-
-use std;
+use std::{self, error, result};
 use state_machine;
 use runtime_primitives::ApplyError;
 use consensus;
-use error_chain::*;
+use derive_more::{Display, From};
 
-error_chain! {
-	links {
-		Consensus(consensus::Error, consensus::ErrorKind);
-	}
-	errors {
-		/// Backend error.
-		Backend(s: String) {
-			description("Unrecoverable backend error"),
-			display("Backend error: {}", s),
-		}
+/// Client Result type alias
+pub type Result<T> = result::Result<T, Error>;
 
-		/// Unknown block.
-		UnknownBlock(h: String) {
-			description("unknown block"),
-			display("UnknownBlock: {}", &*h),
-		}
+/// Substrate Client error
+#[derive(Debug, Display, From)]
+pub enum Error {
+	/// Consensus Error
+	#[display(fmt = "Consensus: {}", _0)]
+	Consensus(consensus::Error),
+	/// Backend error.
+	#[display(fmt = "Backend error: {}", _0)]
+	Backend(String),
+	/// Unknown block.
+	#[display(fmt = "UnknownBlock: {}", _0)]
+	UnknownBlock(String),
+	/// Applying extrinsic error.
+	#[display(fmt = "Extrinsic error: {:?}", _0)]
+	ApplyExtrinsicFailed(ApplyError),
+	/// Execution error.
+	#[display(fmt = "Execution: {}", _0)]
+	Execution(Box<state_machine::Error>),
+	/// Blockchain error.
+	#[display(fmt = "Blockchain: {}", _0)]
+	Blockchain(Box<Error>),
+	/// Invalid authorities set received from the runtime.
+	#[display(fmt = "Current state of blockchain has invalid authorities set")]
+	InvalidAuthoritiesSet,
+	/// Could not get runtime version.
+	#[display(fmt = "On-chain runtime does not specify version")]
+	VersionInvalid,
+	/// Genesis config is invalid.
+	#[display(fmt = "Genesis config provided is invalid")]
+	GenesisInvalid,
+	/// Bad justification for header.
+	#[display(fmt = "bad justification for header: {}", _0)]
+	BadJustification(String),
+	/// Not available on light client.
+	#[display(fmt = "This method is not currently available when running in light client mode")]
+	NotAvailableOnLightClient,
+	/// Invalid remote CHT-based proof.
+	#[display(fmt = "Remote node has responded with invalid header proof")]
+	InvalidCHTProof,
+	/// Remote fetch has been cancelled.
+	#[display(fmt = "Remote data fetch has been cancelled")]
+	RemoteFetchCancelled,
+	/// Remote fetch has been failed.
+	#[display(fmt = "Remote data fetch has been failed")]
+	RemoteFetchFailed,
+	/// Error decoding call result.
+	#[display(fmt = "Error decoding call result of {}", _0)]
+	CallResultDecode(&'static str),
+	/// Error converting a parameter between runtime and node.
+	#[display(fmt = "Error converting `{}` between runtime and node", _0)]
+	RuntimeParamConversion(&'static str),
+	/// Changes tries are not supported.
+	#[display(fmt = "Changes tries are not supported by the runtime")]
+	ChangesTriesNotSupported,
+	/// Key changes query has failed.
+	#[display(fmt = "Failed to check changes proof: {}", _0)]
+	ChangesTrieAccessFailed(String),
+	/// Last finalized block not parent of current.
+	#[display(fmt = "Did not finalize blocks in sequential order.")]
+	NonSequentialFinalization(String),
+	/// Safety violation: new best block not descendent of last finalized.
+	#[display(fmt = "Potential long-range attack: block not in finalized chain.")]
+	NotInFinalizedChain,
+	/// Hash that is required for building CHT is missing.
+	#[display(fmt = "Failed to get hash of block#{} for building CHT#{}", _0, _1)]
+	MissingHashRequiredForCHT(u64, u64),
+	/// A convenience variant for String
+	#[display(fmt = "{}", _0)]
+	Msg(String),
+}
 
-		/// Applying extrinsic error.
-		ApplyExtrinsicFailed(e: ApplyError) {
-			description("Extrinsic error"),
-			display("Extrinsic error: {:?}", e),
-		}
-
-		/// Execution error.
-		Execution(e: Box<state_machine::Error>) {
-			description("execution error"),
-			display("Execution: {}", e),
-		}
-
-		/// Blockchain error.
-		Blockchain(e: Box<std::error::Error + Send>) {
-			description("Blockchain error"),
-			display("Blockchain: {}", e),
-		}
-
-		/// Could not get runtime version.
-		VersionInvalid {
-			description("Runtime version error"),
-			display("On-chain runtime does not specify version"),
-		}
-
-		/// Genesis config is invalid.
-		GenesisInvalid {
-			description("Genesis config error"),
-			display("Genesis config provided is invalid"),
-		}
-
-		/// Bad justification for header.
-		BadJustification(h: String) {
-			description("bad justification for header"),
-			display("bad justification for header: {}", &*h),
-		}
-
-		/// Not available on light client.
-		NotAvailableOnLightClient {
-			description("not available on light client"),
-			display("This method is not currently available when running in light client mode"),
-		}
-
-		/// Invalid remote CHT-based proof.
-		InvalidCHTProof {
-			description("invalid header proof"),
-			display("Remote node has responded with invalid header proof"),
-		}
-
-		/// Remote fetch has been cancelled.
-		RemoteFetchCancelled {
-			description("remote fetch cancelled"),
-			display("Remote data fetch has been cancelled"),
-		}
-
-		/// Remote fetch has been failed.
-		RemoteFetchFailed {
-			description("remote fetch failed"),
-			display("Remote data fetch has been failed"),
-		}
-
-		/// Error decoding call result.
-		CallResultDecode(method: &'static str) {
-			description("Error decoding call result")
-			display("Error decoding call result of {}", method)
-		}
-
-		/// Error converting a parameter between runtime and node.
-		RuntimeParamConversion(param: &'static str) {
-			description("Error converting parameter between runtime and node")
-			display("Error converting `{}` between runtime and node", param)
-		}
-
-		/// Changes tries are not supported.
-		ChangesTriesNotSupported {
-			description("changes tries are not supported"),
-			display("Changes tries are not supported by the runtime"),
-		}
-
-		/// Key changes query has failed.
-		ChangesTrieAccessFailed(e: String) {
-			description("invalid changes proof"),
-			display("Failed to check changes proof: {}", e),
-		}
-
-		/// Last finalized block not parent of current.
-		NonSequentialFinalization(s: String) {
-			description("Did not finalize blocks in sequential order."),
-			display("Did not finalize blocks in sequential order."),
-		}
-
-		/// Safety violation: new best block not descendent of last finalized.
-		NotInFinalizedChain {
-			description("Potential long-range attack: block not in finalized chain."),
-			display("Potential long-range attack: block not in finalized chain."),
-		}
-
-		/// Hash that is required for building CHT is missing.
-		MissingHashRequiredForCHT(cht_num: u64, block_number: u64) {
-			description("missed hash required for building CHT"),
-			display("Failed to get hash of block#{} for building CHT#{}", block_number, cht_num),
+impl error::Error for Error {
+	fn source(&self) -> Option<&(error::Error + 'static)> {
+		match self {
+			Error::Consensus(e) => Some(e),
+			Error::Blockchain(e) => Some(e),
+			_ => None,
 		}
 	}
 }
 
-impl From<Box<state_machine::Error>> for Error {
-	fn from(e: Box<state_machine::Error>) -> Self {
-		ErrorKind::Execution(e).into()
+impl From<String> for Error {
+	fn from(s: String) -> Self {
+		Error::Msg(s)
 	}
 }
 
-impl From<state_machine::backend::Void> for Error {
-	fn from(e: state_machine::backend::Void) -> Self {
-		match e {}
+impl<'a> From<&'a str> for Error {
+	fn from(s: &'a str) -> Self {
+		Error::Msg(s.into())
 	}
 }
 
 impl Error {
 	/// Chain a blockchain error.
-	pub fn from_blockchain(e: Box<std::error::Error + Send>) -> Self {
-		ErrorKind::Blockchain(e).into()
+	pub fn from_blockchain(e: Box<Error>) -> Self {
+		Error::Blockchain(e)
 	}
 
 	/// Chain a state error.
 	pub fn from_state(e: Box<state_machine::Error + Send>) -> Self {
-		ErrorKind::Execution(e).into()
+		Error::Execution(e)
 	}
 }
 

substrate/core/client/src/in_mem.rs

@@ -207,7 +207,7 @@ impl<Block: BlockT> Blockchain<Block> {
 	pub fn set_head(&self, id: BlockId<Block>) -> error::Result<()> {
 		let header = match self.header(id)? {
 			Some(h) => h,
-			None => return Err(error::ErrorKind::UnknownBlock(format!("{}", id)).into()),
+			None => return Err(error::Error::UnknownBlock(format!("{}", id))),
 		};
 
 		self.apply_head(&header)
@@ -258,7 +258,7 @@ impl<Block: BlockT> Blockchain<Block> {
 	fn finalize_header(&self, id: BlockId<Block>, justification: Option<Justification>) -> error::Result<()> {
 		let hash = match self.header(id)? {
 			Some(h) => h.hash(),
-			None => return Err(error::ErrorKind::UnknownBlock(format!("{}", id)).into()),
+			None => return Err(error::Error::UnknownBlock(format!("{}", id))),
 		};
 
 		let mut storage = self.storage.write();
@@ -416,12 +416,12 @@ impl<Block: BlockT> light::blockchain::Storage<Block> for Blockchain<Block>
 
 	fn header_cht_root(&self, _cht_size: u64, block: NumberFor<Block>) -> error::Result<Block::Hash> {
 		self.storage.read().header_cht_roots.get(&block).cloned()
-			.ok_or_else(|| error::ErrorKind::Backend(format!("Header CHT for block {} not exists", block)).into())
+			.ok_or_else(|| error::Error::Backend(format!("Header CHT for block {} not exists", block)))
 	}
 
 	fn changes_trie_cht_root(&self, _cht_size: u64, block: NumberFor<Block>) -> error::Result<Block::Hash> {
 		self.storage.read().changes_trie_cht_roots.get(&block).cloned()
-			.ok_or_else(|| error::ErrorKind::Backend(format!("Changes trie CHT for block {} not exists", block)).into())
+			.ok_or_else(|| error::Error::Backend(format!("Changes trie CHT for block {} not exists", block)))
 	}
 
 	fn cache(&self) -> Option<Arc<blockchain::Cache<Block>>> {
@@ -665,7 +665,7 @@ where
 
 		match self.blockchain.id(block).and_then(|id| self.states.read().get(&id).cloned()) {
 			Some(state) => Ok(state),
-			None => Err(error::ErrorKind::UnknownBlock(format!("{}", block)).into()),
+			None => Err(error::Error::UnknownBlock(format!("{}", block))),
 		}
 	}
 
@@ -717,11 +717,11 @@ impl<H: Hasher> state_machine::ChangesTrieStorage<H> for ChangesTrieStorage<H> w
 /// Check that genesis storage is valid.
 pub fn check_genesis_storage(top: &StorageOverlay, children: &ChildrenStorageOverlay) -> error::Result<()> {
 	if top.iter().any(|(k, _)| well_known_keys::is_child_storage_key(k)) {
-		return Err(error::ErrorKind::GenesisInvalid.into());
+		return Err(error::Error::GenesisInvalid.into());
 	}
 
 	if children.keys().any(|child_key| !well_known_keys::is_child_storage_key(&child_key)) {
-		return Err(error::ErrorKind::GenesisInvalid.into());
+		return Err(error::Error::GenesisInvalid.into());
 	}
 
 	Ok(())

substrate/core/client/src/leaves.rs

@@ -85,11 +85,11 @@ impl<H, N> LeafSet<H, N> where
 			let raw_hash = &mut &key[prefix.len()..];
 			let hash = match Decode::decode(raw_hash) {
 				Some(hash) => hash,
-				None => return Err(error::ErrorKind::Backend("Error decoding hash".into()).into()),
+				None => return Err(error::Error::Backend("Error decoding hash".into())),
 			};
 			let number = match Decode::decode(&mut &value[..]) {
 				Some(number) => number,
-				None => return Err(error::ErrorKind::Backend("Error decoding number".into()).into()),
+				None => return Err(error::Error::Backend("Error decoding number".into())),
 			};
 			storage.entry(Reverse(number)).or_insert_with(Vec::new).push(hash);
 		}

substrate/core/client/src/light/backend.rs

@@ -28,7 +28,7 @@ use runtime_primitives::traits::{Block as BlockT, NumberFor, Zero, Header};
 use crate::in_mem::{self, check_genesis_storage};
 use crate::backend::{AuxStore, Backend as ClientBackend, BlockImportOperation, RemoteBackend, NewBlockState};
 use crate::blockchain::HeaderBackend as BlockchainHeaderBackend;
-use crate::error::{Error as ClientError, ErrorKind as ClientErrorKind, Result as ClientResult};
+use crate::error::{Error as ClientError, Result as ClientResult};
 use crate::light::blockchain::{Blockchain, Storage as BlockchainStorage};
 use crate::light::fetcher::{Fetcher, RemoteReadRequest};
 use hash_db::Hasher;
@@ -208,7 +208,7 @@ impl<S, F, Block, H> ClientBackend<Block, H> for Backend<S, F, H> where
 	}
 
 	fn revert(&self, _n: NumberFor<Block>) -> ClientResult<NumberFor<Block>> {
-		Err(ClientErrorKind::NotAvailableOnLightClient.into())
+		Err(ClientError::NotAvailableOnLightClient.into())
 	}
 }
 
@@ -323,13 +323,13 @@ where
 		let mut header = self.cached_header.read().clone();
 		if header.is_none() {
 			let cached_header = self.blockchain.upgrade()
-				.ok_or_else(|| ClientErrorKind::UnknownBlock(format!("{}", self.block)).into())
+				.ok_or_else(|| ClientError::UnknownBlock(format!("{}", self.block)))
 				.and_then(|blockchain| blockchain.expect_header(BlockId::Hash(self.block)))?;
 			header = Some(cached_header.clone());
 			*self.cached_header.write() = Some(cached_header);
 		}
 
-		self.fetcher.upgrade().ok_or(ClientErrorKind::NotAvailableOnLightClient)?
+		self.fetcher.upgrade().ok_or(ClientError::NotAvailableOnLightClient)?
 			.remote_read(RemoteReadRequest {
 				block: self.block,
 				header: header.expect("if block above guarantees that header is_some(); qed"),
@@ -340,7 +340,7 @@ where
 	}
 
 	fn child_storage(&self, _storage_key: &[u8], _key: &[u8]) -> ClientResult<Option<Vec<u8>>> {
-		Err(ClientErrorKind::NotAvailableOnLightClient.into())
+		Err(ClientError::NotAvailableOnLightClient.into())
 	}
 
 	fn for_keys_with_prefix<A: FnMut(&[u8])>(&self, _prefix: &[u8], _action: A) {

substrate/core/client/src/light/blockchain.rs

@@ -29,7 +29,7 @@ use crate::backend::{AuxStore, NewBlockState};
 use crate::blockchain::{Backend as BlockchainBackend, BlockStatus, Cache as BlockchainCache,
 	HeaderBackend as BlockchainHeaderBackend, Info as BlockchainInfo, ProvideCache};
 use crate::cht;
-use crate::error::{ErrorKind as ClientErrorKind, Result as ClientResult};
+use crate::error::{Error as ClientError, Result as ClientResult};
 use crate::light::fetcher::{Fetcher, RemoteHeaderRequest};
 
 /// Light client blockchain storage.
@@ -114,7 +114,7 @@ impl<S, F, Block> BlockchainHeaderBackend<Block> for Blockchain<S, F> where Bloc
 					return Ok(None);
 				}
 
-				self.fetcher().upgrade().ok_or(ClientErrorKind::NotAvailableOnLightClient)?
+				self.fetcher().upgrade().ok_or(ClientError::NotAvailableOnLightClient)?
 					.remote_header(RemoteHeaderRequest {
 						cht_root: self.storage.header_cht_root(cht::SIZE, number)?,
 						block: number,
@@ -202,22 +202,22 @@ pub mod tests {
 
 	impl BlockchainHeaderBackend<Block> for DummyStorage {
 		fn header(&self, _id: BlockId<Block>) -> ClientResult<Option<Header>> {
-			Err(ClientErrorKind::Backend("Test error".into()).into())
+			Err(ClientError::Backend("Test error".into()))
 		}
 
 		fn info(&self) -> ClientResult<Info<Block>> {
-			Err(ClientErrorKind::Backend("Test error".into()).into())
+			Err(ClientError::Backend("Test error".into()))
 		}
 
 		fn status(&self, _id: BlockId<Block>) -> ClientResult<BlockStatus> {
-			Err(ClientErrorKind::Backend("Test error".into()).into())
+			Err(ClientError::Backend("Test error".into()))
 		}
 
 		fn number(&self, hash: Hash) -> ClientResult<Option<NumberFor<Block>>> {
 			if hash == Default::default() {
 				Ok(Some(Default::default()))
 			} else {
-				Err(ClientErrorKind::Backend("Test error".into()).into())
+				Err(ClientError::Backend("Test error".into()))
 			}
 		}
 
@@ -225,7 +225,7 @@ pub mod tests {
 			if number == 0 {
 				Ok(Some(Default::default()))
 			} else {
-				Err(ClientErrorKind::Backend("Test error".into()).into())
+				Err(ClientError::Backend("Test error".into()))
 			}
 		}
 	}
@@ -261,26 +261,26 @@ pub mod tests {
 		}
 
 		fn set_head(&self, _block: BlockId<Block>) -> ClientResult<()> {
-			Err(ClientErrorKind::Backend("Test error".into()).into())
+			Err(ClientError::Backend("Test error".into()))
 		}
 
 		fn finalize_header(&self, _block: BlockId<Block>) -> ClientResult<()> {
-			Err(ClientErrorKind::Backend("Test error".into()).into())
+			Err(ClientError::Backend("Test error".into()))
 		}
 
 		fn last_finalized(&self) -> ClientResult<Hash> {
-			Err(ClientErrorKind::Backend("Test error".into()).into())
+			Err(ClientError::Backend("Test error".into()))
 		}
 
 		fn header_cht_root(&self, _cht_size: u64, _block: u64) -> ClientResult<Hash> {
-			Err(ClientErrorKind::Backend("Test error".into()).into())
+			Err(ClientError::Backend("Test error".into()))
 		}
 
 		fn changes_trie_cht_root(&self, cht_size: u64, block: u64) -> ClientResult<Hash> {
 			cht::block_to_cht_number(cht_size, block)
 				.and_then(|cht_num| self.changes_tries_cht_roots.get(&cht_num))
 				.cloned()
-				.ok_or_else(|| ClientErrorKind::Backend(
+				.ok_or_else(|| ClientError::Backend(
 					format!("Test error: CHT for block #{} not found", block)
 				).into())
 		}

substrate/core/client/src/light/call_executor.rs

@@ -31,7 +31,7 @@ use hash_db::Hasher;
 use crate::backend::RemoteBackend;
 use crate::blockchain::Backend as ChainBackend;
 use crate::call_executor::CallExecutor;
-use crate::error::{Error as ClientError, ErrorKind as ClientErrorKind, Result as ClientResult};
+use crate::error::{Error as ClientError, Result as ClientResult};
 use crate::light::fetcher::{Fetcher, RemoteCallRequest};
 use executor::{RuntimeVersion, NativeVersion};
 use heapsize::HeapSizeOf;
@@ -126,7 +126,7 @@ where
 	) -> ClientResult<NativeOrEncoded<R>> where ExecutionManager<EM>: Clone {
 		// it is only possible to execute contextual call if changes are empty
 		if !changes.is_empty() || initialized_block.is_some() {
-			return Err(ClientErrorKind::NotAvailableOnLightClient.into());
+			return Err(ClientError::NotAvailableOnLightClient.into());
 		}
 
 		self.call(at, method, call_data, (&execution_manager).into(), side_effects_handler).map(NativeOrEncoded::Encoded)
@@ -135,7 +135,7 @@ where
 	fn runtime_version(&self, id: &BlockId<Block>) -> ClientResult<RuntimeVersion> {
 		let call_result = self.call(id, "version", &[], ExecutionStrategy::NativeElseWasm, NeverOffchainExt::new())?;
 		RuntimeVersion::decode(&mut call_result.as_slice())
-			.ok_or_else(|| ClientErrorKind::VersionInvalid.into())
+			.ok_or_else(|| ClientError::VersionInvalid.into())
 	}
 
 	fn call_at_state<
@@ -156,7 +156,7 @@ where
 		_native_call: Option<NC>,
 		_side_effects_handler: Option<&mut O>,
 	) -> ClientResult<(NativeOrEncoded<R>, S::Transaction, Option<MemoryDB<Blake2Hasher>>)> {
-		Err(ClientErrorKind::NotAvailableOnLightClient.into())
+		Err(ClientError::NotAvailableOnLightClient.into())
 	}
 
 	fn prove_at_trie_state<S: state_machine::TrieBackendStorage<Blake2Hasher>>(
@@ -166,7 +166,7 @@ where
 		_method: &str,
 		_call_data: &[u8]
 	) -> ClientResult<(Vec<u8>, Vec<Vec<u8>>)> {
-		Err(ClientErrorKind::NotAvailableOnLightClient.into())
+		Err(ClientError::NotAvailableOnLightClient.into())
 	}
 
 	fn native_runtime_version(&self) -> Option<&NativeVersion> {
@@ -275,7 +275,7 @@ impl<Block, B, Remote, Local> CallExecutor<Block, Blake2Hasher> for
 				ExecutionManager::NativeWhenPossible,
 				native_call,
 				side_effects_handler,
-			).map_err(|e| ClientErrorKind::Execution(Box::new(e.to_string())).into()),
+			).map_err(|e| ClientError::Execution(Box::new(e.to_string()))),
 			false => CallExecutor::contextual_call::<
 				_,
 				_,
@@ -296,7 +296,7 @@ impl<Block, B, Remote, Local> CallExecutor<Block, Blake2Hasher> for
 				ExecutionManager::NativeWhenPossible,
 				native_call,
 				side_effects_handler,
-			).map_err(|e| ClientErrorKind::Execution(Box::new(e.to_string())).into()),
+			).map_err(|e| ClientError::Execution(Box::new(e.to_string()))),
 		}
 	}
 
@@ -346,7 +346,7 @@ impl<Block, B, Remote, Local> CallExecutor<Block, Blake2Hasher> for
 				ExecutionManager::NativeWhenPossible,
 				native_call,
 				side_effects_handler,
-			).map_err(|e| ClientErrorKind::Execution(Box::new(e.to_string())).into())
+			).map_err(|e| ClientError::Execution(Box::new(e.to_string())))
 	}
 
 	fn prove_at_trie_state<S: state_machine::TrieBackendStorage<Blake2Hasher>>(

substrate/core/client/src/light/fetcher.rs

@@ -29,7 +29,7 @@ use state_machine::{CodeExecutor, ChangesTrieRootsStorage, ChangesTrieAnchorBloc
 	TrieBackend, read_proof_check, key_changes_proof_check, create_proof_check_backend_storage};
 
 use crate::cht;
-use crate::error::{Error as ClientError, ErrorKind as ClientErrorKind, Result as ClientResult};
+use crate::error::{Error as ClientError, Result as ClientResult};
 use crate::light::blockchain::{Blockchain, Storage as BlockchainStorage};
 use crate::light::call_executor::check_execution_proof;
 
@@ -193,7 +193,7 @@ impl<E, H, B: BlockT, S: BlockchainStorage<B>, F> LightDataChecker<E, H, B, S, F
 		// since we need roots of all changes tries for the range begin..max
 		// => remote node can't use max block greater that one that we have passed
 		if remote_proof.max_block > request.max_block.0 || remote_proof.max_block < request.last_block.0 {
-			return Err(ClientErrorKind::ChangesTrieAccessFailed(format!(
+			return Err(ClientError::ChangesTrieAccessFailed(format!(
 				"Invalid max_block used by the remote node: {}. Local: {}..{}..{}",
 				remote_proof.max_block, request.first_block.0, request.last_block.0, request.max_block.0,
 			)).into());
@@ -209,7 +209,7 @@ impl<E, H, B: BlockT, S: BlockchainStorage<B>, F> LightDataChecker<E, H, B, S, F
 			.map(|last_root| *last_root >= request.tries_roots.0)
 			.unwrap_or(false);
 		if is_extra_first_root || is_extra_last_root {
-			return Err(ClientErrorKind::ChangesTrieAccessFailed(format!(
+			return Err(ClientError::ChangesTrieAccessFailed(format!(
 				"Extra changes tries roots proofs provided by the remote node: [{:?}..{:?}]. Expected in range: [{}; {})",
 				remote_proof.roots.keys().next(), remote_proof.roots.keys().next_back(),
 				request.first_block.0, request.tries_roots.0,
@@ -247,7 +247,7 @@ impl<E, H, B: BlockT, S: BlockchainStorage<B>, F> LightDataChecker<E, H, B, S, F
 			remote_max_block.as_(),
 			&request.key)
 		.map(|pairs| pairs.into_iter().map(|(b, x)| (As::sa(b), x)).collect())
-		.map_err(|err| ClientErrorKind::ChangesTrieAccessFailed(err).into())
+		.map_err(|err| ClientError::ChangesTrieAccessFailed(err))
 	}
 
 	/// Check CHT-based proof for changes tries roots.
@@ -283,7 +283,7 @@ impl<E, H, B: BlockT, S: BlockchainStorage<B>, F> LightDataChecker<E, H, B, S, F
 				let mut cht_root = H::Out::default();
 				cht_root.as_mut().copy_from_slice(local_cht_root.as_ref());
 				if !storage.contains(&cht_root, &[]) {
-					return Err(ClientErrorKind::InvalidCHTProof.into());
+					return Err(ClientError::InvalidCHTProof.into());
 				}
 
 				// check proof for single changes trie root
@@ -320,7 +320,7 @@ impl<E, Block, H, S, F> FetchChecker<Block> for LightDataChecker<E, H, Block, S,
 		remote_proof: Vec<Vec<u8>>
 	) -> ClientResult<Block::Header> {
 		let remote_header = remote_header.ok_or_else(||
-			ClientError::from(ClientErrorKind::InvalidCHTProof))?;
+			ClientError::from(ClientError::InvalidCHTProof))?;
 		let remote_header_hash = remote_header.hash();
 		cht::check_proof::<Block::Header, H>(
 			request.cht_root,
@@ -473,7 +473,7 @@ pub mod tests {
 			let builder = remote_client.new_block().unwrap();
 			remote_client.import(BlockOrigin::Own, builder.bake().unwrap()).unwrap();
 			local_headers_hashes.push(remote_client.block_hash(i + 1)
-				.map_err(|_| ClientErrorKind::Backend("TestError".into()).into()));
+				.map_err(|_| ClientError::Backend("TestError".into())));
 		}
 
 		// 'fetch' header proof from remote node