Move ethcore::Error to error_chain (#8386)

* WIP

* Convert Ethcore error to use error_chain

* Use error_chain for ImportError and BlockImportError

* Fix error pattern matches for error_chain in miner

* Implement explicit From for AccountsError

* Fix pattern matches for ErrorKinds

* Handle ethcore error_chain in light client

* Explicitly define Result type to avoid shadowing

* Fix remaining Error pattern matches

* Fix tab space formatting

* Helps if the tests compile

* Fix error chain matching after merge

ethcore/src/verification/queue/kind.rs

@@ -69,7 +69,7 @@ pub mod blocks {
 	use super::{Kind, BlockLike};
 
 	use engines::EthEngine;
-	use error::{Error, BlockError};
+	use error::{Error, ErrorKind, BlockError};
 	use header::Header;
 	use verification::{PreverifiedBlock, verify_block_basic, verify_block_unordered};
 
@@ -88,7 +88,7 @@ pub mod blocks {
 		fn create(input: Self::Input, engine: &EthEngine) -> Result<Self::Unverified, Error> {
 			match verify_block_basic(&input.header, &input.bytes, engine) {
 				Ok(()) => Ok(input),
-				Err(Error::Block(BlockError::TemporarilyInvalid(oob))) => {
+				Err(Error(ErrorKind::Block(BlockError::TemporarilyInvalid(oob)), _)) => {
 					debug!(target: "client", "Block received too early {}: {:?}", input.hash(), oob);
 					Err(BlockError::TemporarilyInvalid(oob).into())
 				},

ethcore/src/verification/queue/mod.rs

@@ -472,17 +472,17 @@ impl<K: Kind> VerificationQueue<K> {
 		let h = input.hash();
 		{
 			if self.processing.read().contains_key(&h) {
-				return Err(ImportError::AlreadyQueued.into());
+				bail!(ErrorKind::Import(ImportErrorKind::AlreadyQueued));
 			}
 
 			let mut bad = self.verification.bad.lock();
 			if bad.contains(&h) {
-				return Err(ImportError::KnownBad.into());
+				bail!(ErrorKind::Import(ImportErrorKind::KnownBad));
 			}
 
 			if bad.contains(&input.parent_hash()) {
 				bad.insert(h.clone());
-				return Err(ImportError::KnownBad.into());
+				bail!(ErrorKind::Import(ImportErrorKind::KnownBad));
 			}
 		}
 
@@ -502,7 +502,7 @@ impl<K: Kind> VerificationQueue<K> {
 			Err(err) => {
 				match err {
 					// Don't mark future blocks as bad.
-					Error::Block(BlockError::TemporarilyInvalid(_)) => {},
+					Error(ErrorKind::Block(BlockError::TemporarilyInvalid(_)), _) => {},
 					_ => {
 						self.verification.bad.lock().insert(h.clone());
 					}
@@ -773,7 +773,7 @@ mod tests {
 		match duplicate_import {
 			Err(e) => {
 				match e {
-					Error::Import(ImportError::AlreadyQueued) => {},
+					Error(ErrorKind::Import(ImportErrorKind::AlreadyQueued), _) => {},
 					_ => { panic!("must return AlreadyQueued error"); }
 				}
 			}