[ethcore] remove error_chain (#10616)

* Derive Display for BlockError

* Convert error_chain errors

* Convert ethcore usages of errors

* Fix remaining compile errors in ethcore

* Fix other crates

* Fix tests compilation

* Implement error for Snapshot error

* Remove redundant into

ethcore/src/snapshot/error.rs

@@ -16,6 +16,7 @@
 
 //! Snapshot-related errors.
 
+use std::error;
 use std::fmt;
 
 use types::ids::BlockId;
@@ -69,6 +70,17 @@ pub enum Error {
 	UnlinkedAncientBlockChain,
 }
 
+impl error::Error for Error {
+	fn source(&self) -> Option<&(error::Error + 'static)> {
+		match self {
+			Error::Trie(e) => Some(e),
+			Error::Decoder(e) => Some(e),
+			Error::Io(e) => Some(e),
+			_ => None,
+		}
+	}
+}
+
 impl fmt::Display for Error {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		match *self {

ethcore/src/snapshot/service.rs

@@ -30,7 +30,7 @@ use super::io::{SnapshotReader, LooseReader, SnapshotWriter, LooseWriter};
 use blockchain::{BlockChain, BlockChainDB, BlockChainDBHandler};
 use client::{BlockInfo, BlockChainClient, Client, ChainInfo, ClientIoMessage};
 use engines::EthEngine;
-use error::{Error, ErrorKind as SnapshotErrorKind};
+use error::Error;
 use snapshot::{Error as SnapshotError};
 use hash::keccak;
 use types::ids::BlockId;
@@ -697,7 +697,7 @@ impl Service {
 		let mut restoration = self.restoration.lock();
 		match self.feed_chunk_with_restoration(&mut restoration, hash, chunk, is_state) {
 			Ok(()) |
-			Err(Error(SnapshotErrorKind::Snapshot(SnapshotError::RestorationAborted), _)) => (),
+			Err(Error::Snapshot(SnapshotError::RestorationAborted)) => (),
 			Err(e) => {
 				warn!("Encountered error during snapshot restoration: {}", e);
 				*self.restoration.lock() = None;

ethcore/src/snapshot/tests/proof_of_work.rs

@@ -18,7 +18,7 @@
 
 use std::sync::atomic::AtomicBool;
 use tempdir::TempDir;
-use error::{Error, ErrorKind};
+use error::Error;
 
 use blockchain::generator::{BlockGenerator, BlockBuilder};
 use blockchain::{BlockChain, ExtrasInsert};
@@ -143,7 +143,7 @@ fn checks_flag() {
 	let mut rebuilder = SNAPSHOT_MODE.rebuilder(chain, db.clone(), &manifest).unwrap();
 
 	match rebuilder.feed(&chunk, engine.as_ref(), &AtomicBool::new(false)) {
-		Err(Error(ErrorKind::Snapshot(SnapshotError::RestorationAborted), _)) => {}
+		Err(Error::Snapshot(SnapshotError::RestorationAborted)) => {}
 		_ => panic!("Wrong result on abort flag set")
 	}
 }

ethcore/src/snapshot/tests/state.rs

@@ -26,7 +26,7 @@ use snapshot::{chunk_state, Error as SnapshotError, Progress, StateRebuilder, SN
 use snapshot::io::{PackedReader, PackedWriter, SnapshotReader, SnapshotWriter};
 use super::helpers::StateProducer;
 
-use error::{Error, ErrorKind};
+use error::Error;
 
 use rand::{XorShiftRng, SeedableRng};
 use ethereum_types::H256;
@@ -196,7 +196,7 @@ fn checks_flag() {
 			let chunk = ::snappy::decompress(&raw).unwrap();
 
 			match rebuilder.feed(&chunk, &flag) {
-				Err(Error(ErrorKind::Snapshot(SnapshotError::RestorationAborted), _)) => {},
+				Err(Error::Snapshot(SnapshotError::RestorationAborted)) => {},
 				_ => panic!("unexpected result when feeding with flag off"),
 			}
 		}