Port try macro to new ? operator. (#3962)

* initial untry sweep

* restore try in ipc codegen, fix inference

* change a few missed try instances

dapps/src/apps/fetcher/installers.rs

@@ -35,30 +35,30 @@ fn write_response_and_check_hash(
 	response: fetch::Response
 ) -> Result<(fs::File, PathBuf), ValidationError> {
 	// try to parse id
-	let id = try!(id.parse().map_err(|_| ValidationError::InvalidContentId));
+	let id = id.parse().map_err(|_| ValidationError::InvalidContentId)?;
 
 	// check if content exists
 	if content_path.exists() {
 		warn!(target: "dapps", "Overwriting existing content at 0x{:?}", id);
-		try!(fs::remove_dir_all(&content_path))
+		fs::remove_dir_all(&content_path)?
 	}
 
 	// create directory
-	try!(fs::create_dir_all(&content_path));
+	fs::create_dir_all(&content_path)?;
 
 	// append filename
 	content_path.push(filename);
 
 	// Now write the response
-	let mut file = io::BufWriter::new(try!(fs::File::create(&content_path)));
+	let mut file = io::BufWriter::new(fs::File::create(&content_path)?);
 	let mut reader = io::BufReader::new(response);
-	try!(io::copy(&mut reader, &mut file));
-	try!(file.flush());
+	io::copy(&mut reader, &mut file)?;
+	file.flush()?;
 
 	// Validate hash
 	// TODO [ToDr] calculate sha3 in-flight while reading the response
-	let mut file = io::BufReader::new(try!(fs::File::open(&content_path)));
-	let hash = try!(sha3(&mut file));
+	let mut file = io::BufReader::new(fs::File::open(&content_path)?);
+	let hash = sha3(&mut file)?;
 	if id == hash {
 		Ok((file.into_inner(), content_path))
 	} else {
@@ -93,7 +93,7 @@ impl ContentValidator for Content {
 	fn validate_and_install(&self, response: fetch::Response) -> Result<ValidatorResponse, ValidationError> {
 		let validate = |content_path: PathBuf| {
 			// Create dir
-			let (_, content_path) = try!(write_response_and_check_hash(self.id.as_str(), content_path.clone(), self.id.as_str(), response));
+			let (_, content_path) = write_response_and_check_hash(self.id.as_str(), content_path.clone(), self.id.as_str(), response)?;
 
 			Ok(LocalPageEndpoint::single_file(content_path, self.mime.clone(), PageCache::Enabled))
 		};
@@ -131,7 +131,7 @@ impl Dapp {
 
 	fn find_manifest(zip: &mut zip::ZipArchive<fs::File>) -> Result<(Manifest, PathBuf), ValidationError> {
 		for i in 0..zip.len() {
-			let mut file = try!(zip.by_index(i));
+			let mut file = zip.by_index(i)?;
 
 			if !file.name().ends_with(MANIFEST_FILENAME) {
 				continue;
@@ -159,18 +159,18 @@ impl ContentValidator for Dapp {
 
 	fn validate_and_install(&self, response: fetch::Response) -> Result<ValidatorResponse, ValidationError> {
 		let validate = |dapp_path: PathBuf| {
-			let (file, zip_path) = try!(write_response_and_check_hash(self.id.as_str(), dapp_path.clone(), &format!("{}.zip", self.id), response));
+			let (file, zip_path) = write_response_and_check_hash(self.id.as_str(), dapp_path.clone(), &format!("{}.zip", self.id), response)?;
 			trace!(target: "dapps", "Opening dapp bundle at {:?}", zip_path);
 			// Unpack archive
-			let mut zip = try!(zip::ZipArchive::new(file));
+			let mut zip = zip::ZipArchive::new(file)?;
 			// First find manifest file
-			let (mut manifest, manifest_dir) = try!(Self::find_manifest(&mut zip));
+			let (mut manifest, manifest_dir) = Self::find_manifest(&mut zip)?;
 			// Overwrite id to match hash
 			manifest.id = self.id.clone();
 
 			// Unpack zip
 			for i in 0..zip.len() {
-				let mut file = try!(zip.by_index(i));
+				let mut file = zip.by_index(i)?;
 				let is_dir = file.name().chars().rev().next() == Some('/');
 
 				let file_path = PathBuf::from(file.name());
@@ -180,22 +180,22 @@ impl ContentValidator for Dapp {
 					let p = dapp_path.join(location_in_manifest_base);
 					// Check if it's a directory
 					if is_dir {
-						try!(fs::create_dir_all(p));
+						fs::create_dir_all(p)?;
 					} else {
-						let mut target = try!(fs::File::create(p));
-						try!(io::copy(&mut file, &mut target));
+						let mut target = fs::File::create(p)?;
+						io::copy(&mut file, &mut target)?;
 					}
 				}
 			}
 
 			// Remove zip
-			try!(fs::remove_file(&zip_path));
+			fs::remove_file(&zip_path)?;
 
 			// Write manifest
-			let manifest_str = try!(serialize_manifest(&manifest).map_err(ValidationError::ManifestSerialization));
+			let manifest_str = serialize_manifest(&manifest).map_err(ValidationError::ManifestSerialization)?;
 			let manifest_path = dapp_path.join(MANIFEST_FILENAME);
-			let mut manifest_file = try!(fs::File::create(manifest_path));
-			try!(manifest_file.write_all(manifest_str.as_bytes()));
+			let mut manifest_file = fs::File::create(manifest_path)?;
+			manifest_file.write_all(manifest_str.as_bytes())?;
 			// Create endpoint
 			let endpoint = LocalPageEndpoint::new(dapp_path, manifest.clone().into(), PageCache::Enabled, self.embeddable_on.clone());
 			Ok(endpoint)

dapps/src/apps/fs.rs

@@ -37,8 +37,8 @@ fn local_dapps(dapps_path: String) -> Vec<LocalDapp> {
 
 	let files = files.expect("Check is done earlier");
 	files.map(|dir| {
-			let entry = try!(dir);
-			let file_type = try!(entry.file_type());
+			let entry = dir?;
+			let file_type = entry.file_type()?;
 
 			// skip files
 			if file_type.is_file() {
@@ -79,7 +79,7 @@ fn read_manifest(name: &str, mut path: PathBuf) -> EndpointInfo {
 		.and_then(|mut f| {
 			// Reat file
 			let mut s = String::new();
-			try!(f.read_to_string(&mut s).map_err(|e| format!("{:?}", e)));
+			f.read_to_string(&mut s).map_err(|e| format!("{:?}", e))?;
 			// Try to deserialize manifest
 			deserialize_manifest(s)
 		})

dapps/src/lib.rs

@@ -188,7 +188,7 @@ impl ServerBuilder {
 			self.sync_status.clone(),
 			self.web_proxy_tokens.clone(),
 			self.remote.clone(),
-			try!(self.fetch()),
+			self.fetch()?,
 		)
 	}
 
@@ -206,7 +206,7 @@ impl ServerBuilder {
 			self.sync_status.clone(),
 			self.web_proxy_tokens.clone(),
 			self.remote.clone(),
-			try!(self.fetch()),
+			self.fetch()?,
 		)
 	}
 
@@ -288,7 +288,7 @@ impl Server {
 		});
 		let hosts = Self::allowed_hosts(hosts, format!("{}", addr));
 
-		try!(hyper::Server::http(addr))
+		hyper::Server::http(addr)?
 			.handle(move |ctrl| router::Router::new(
 				ctrl,
 				signer_address.clone(),

dapps/src/url.rs

@@ -85,9 +85,9 @@ impl Url {
 			_ => None,
 		};
 
-		let port = try!(raw_url.port_or_known_default().ok_or_else(|| format!("Unknown port for scheme: `{}`", raw_url.scheme())));
-		let host = try!(raw_url.host().ok_or_else(|| "Valid host, because only data:, mailto: protocols does not have host.".to_owned())).to_owned();
-		let path = try!(raw_url.path_segments().ok_or_else(|| "Valid path segments. In HTTP we won't get cannot-be-a-base URLs".to_owned()))
+		let port = raw_url.port_or_known_default().ok_or_else(|| format!("Unknown port for scheme: `{}`", raw_url.scheme()))?;
+		let host = raw_url.host().ok_or_else(|| "Valid host, because only data:, mailto: protocols does not have host.".to_owned())?.to_owned();
+		let path = raw_url.path_segments().ok_or_else(|| "Valid path segments. In HTTP we won't get cannot-be-a-base URLs".to_owned())?
 					.map(|part| part.to_owned()).collect();
 		let query = raw_url.query().map(|x| x.to_owned());
 

db/src/database.rs

@@ -73,10 +73,10 @@ impl WriteCache {
 
 				match *cache_entry {
 					WriteCacheEntry::Write(ref val) => {
-						try!(batch.put(&key, val));
+						batch.put(&key, val)?;
 					},
 					WriteCacheEntry::Remove => {
-						try!(batch.delete(&key));
+						batch.delete(&key)?;
 					},
 				}
 				key.clone()
@@ -87,14 +87,14 @@ impl WriteCache {
 			removed_so_far = removed_so_far + 1;
 		}
 		if removed_so_far > 0 {
-			try!(db.write(batch));
+			db.write(batch)?;
 		}
 		Ok(())
 	}
 
 	/// flushes until cache is empty
 	fn flush_all(&mut self, db: &DB) -> Result<(), Error> {
-		while !self.is_empty() { try!(self.flush(db, FLUSH_BATCH_SIZE)); }
+		while !self.is_empty() { self.flush(db, FLUSH_BATCH_SIZE)?; }
 		Ok(())
 	}
 
@@ -104,7 +104,7 @@ impl WriteCache {
 
 	fn try_shrink(&mut self, db: &DB) -> Result<(), Error> {
 		if self.entries.len() > self.preferred_len {
-			try!(self.flush(db, FLUSH_BATCH_SIZE));
+			self.flush(db, FLUSH_BATCH_SIZE)?;
 		}
 		Ok(())
 	}
@@ -135,7 +135,7 @@ impl Database {
 		if db_lock.is_none() { return Ok(()); }
 		let db = db_lock.as_ref().unwrap();
 
-		try!(cache_lock.try_shrink(&db));
+		cache_lock.try_shrink(&db)?;
 		Ok(())
 	}
 
@@ -145,7 +145,7 @@ impl Database {
 		if db_lock.is_none() { return Ok(()); }
 		let db = db_lock.as_ref().expect("we should have exited with Ok(()) on the previous step");
 
-		try!(cache_lock.flush_all(&db));
+		cache_lock.flush_all(&db)?;
 		Ok(())
 
 	}
@@ -174,7 +174,7 @@ impl DatabaseService for Database {
 			opts.set_block_based_table_factory(&block_opts);
 			opts.set_prefix_extractor_fixed_size(size);
 		}
-		*db = Some(try!(DB::open(&opts, &path)));
+		*db = Some(DB::open(&opts, &path)?);
 
 		Ok(())
 	}
@@ -185,7 +185,7 @@ impl DatabaseService for Database {
 	}
 
 	fn close(&self) -> Result<(), Error> {
-		try!(self.flush_all());
+		self.flush_all()?;
 
 		let mut db = self.db.write();
 		if db.is_none() { return Err(Error::IsClosed); }
@@ -231,9 +231,9 @@ impl DatabaseService for Database {
 			}
 		}
 		let db_lock = self.db.read();
-		let db = try!(db_lock.as_ref().ok_or(Error::IsClosed));
+		let db = db_lock.as_ref().ok_or(Error::IsClosed)?;
 
-		match try!(db.get(key)) {
+		match db.get(key)? {
 			Some(db_vec) => {
 				Ok(Some(db_vec.to_vec()))
 			},
@@ -243,7 +243,7 @@ impl DatabaseService for Database {
 
 	fn get_by_prefix(&self, prefix: &[u8]) -> Result<Option<Vec<u8>>, Error> {
 		let db_lock = self.db.read();
-		let db = try!(db_lock.as_ref().ok_or(Error::IsClosed));
+		let db = db_lock.as_ref().ok_or(Error::IsClosed)?;
 
 		let mut iter = db.iterator(IteratorMode::From(prefix, Direction::Forward));
 		match iter.next() {
@@ -255,14 +255,14 @@ impl DatabaseService for Database {
 
 	fn is_empty(&self) -> Result<bool, Error> {
 		let db_lock = self.db.read();
-		let db = try!(db_lock.as_ref().ok_or(Error::IsClosed));
+		let db = db_lock.as_ref().ok_or(Error::IsClosed)?;
 
 		Ok(db.iterator(IteratorMode::Start).next().is_none())
 	}
 
 	fn iter(&self) -> Result<IteratorHandle, Error> {
 		let db_lock = self.db.read();
-		let db = try!(db_lock.as_ref().ok_or(Error::IsClosed));
+		let db = db_lock.as_ref().ok_or(Error::IsClosed)?;
 
 		let mut iterators = self.iterators.write();
 		let next_iterator = iterators.keys().last().unwrap_or(&0) + 1;

db/src/lib.rs.in

@@ -52,27 +52,27 @@ impl std::convert::From<nanoipc::SocketError> for ServiceError {
 
 pub fn blocks_service_url(db_path: &str) -> Result<String, std::io::Error> {
 	let mut path = PathBuf::from(db_path);
-	try!(::std::fs::create_dir_all(db_path));
+	::std::fs::create_dir_all(db_path)?;
 	path.push("blocks.ipc");
 	Ok(format!("ipc://{}", path.to_str().unwrap()))
 }
 
 pub fn extras_service_url(db_path: &str) -> Result<String, ::std::io::Error> {
 	let mut path = PathBuf::from(db_path);
-	try!(::std::fs::create_dir_all(db_path));
+	::std::fs::create_dir_all(db_path)?;
 	path.push("extras.ipc");
 	Ok(format!("ipc://{}", path.to_str().unwrap()))
 }
 
 pub fn blocks_client(db_path: &str) -> Result<DatabaseConnection, ServiceError> {
-	let url = try!(blocks_service_url(db_path));
-	let client = try!(nanoipc::generic_client::<DatabaseClient<_>>(&url));
+	let url = blocks_service_url(db_path)?;
+	let client = nanoipc::generic_client::<DatabaseClient<_>>(&url)?;
 	Ok(client)
 }
 
 pub fn extras_client(db_path: &str) -> Result<DatabaseConnection, ServiceError> {
-	let url = try!(extras_service_url(db_path));
-	let client = try!(nanoipc::generic_client::<DatabaseClient<_>>(&url));
+	let url = extras_service_url(db_path)?;
+	let client = nanoipc::generic_client::<DatabaseClient<_>>(&url)?;
 	Ok(client)
 }
 

ethash/src/compute.rs

@@ -116,17 +116,17 @@ impl Light {
 	pub fn from_file(block_number: u64) -> io::Result<Light> {
 		let seed_compute = SeedHashCompute::new();
 		let path = Light::file_path(seed_compute.get_seedhash(block_number));
-		let mut file = try!(File::open(path));
+		let mut file = File::open(path)?;
 
 		let cache_size = get_cache_size(block_number);
-		if try!(file.metadata()).len() != cache_size as u64 {
+		if file.metadata()?.len() != cache_size as u64 {
 			return Err(io::Error::new(io::ErrorKind::Other, "Cache file size mismatch"));
 		}
 		let num_nodes = cache_size / NODE_BYTES;
 		let mut nodes: Vec<Node> = Vec::new();
 		nodes.resize(num_nodes, unsafe { mem::uninitialized() });
 		let buf = unsafe { slice::from_raw_parts_mut(nodes.as_mut_ptr() as *mut u8, cache_size) };
-		try!(file.read_exact(buf));
+		file.read_exact(buf)?;
 		Ok(Light {
 			cache: nodes,
 			block_number: block_number,
@@ -144,16 +144,16 @@ impl Light {
 
 			if deprecated.exists() {
 				debug!(target: "ethash", "removing: {:?}", &deprecated);
-				try!(fs::remove_file(deprecated));
+				fs::remove_file(deprecated)?;
 			}
 		}
 
-		try!(fs::create_dir_all(path.parent().unwrap()));
-		let mut file = try!(File::create(&path));
+		fs::create_dir_all(path.parent().unwrap())?;
+		let mut file = File::create(&path)?;
 
 		let cache_size = self.cache.len() * NODE_BYTES;
 		let buf = unsafe { slice::from_raw_parts(self.cache.as_ptr() as *const u8, cache_size) };
-		try!(file.write(buf));
+		file.write(buf)?;
 		Ok(path)
 	}
 }

ethcore/light/src/net/buffer_flow.rs

@@ -135,10 +135,10 @@ impl RlpDecodable for CostTable {
 		let mut header_proofs = None;
 
 		for row in rlp.iter() {
-			let msg_id: u8 = try!(row.val_at(0));
+			let msg_id: u8 = row.val_at(0)?;
 			let cost = {
-				let base = try!(row.val_at(1));
-				let per = try!(row.val_at(2));
+				let base = row.val_at(1)?;
+				let per = row.val_at(2)?;
 
 				Cost(base, per)
 			};
@@ -155,12 +155,12 @@ impl RlpDecodable for CostTable {
 		}
 
 		Ok(CostTable {
-			headers: try!(headers.ok_or(DecoderError::Custom("No headers cost specified"))),
-			bodies: try!(bodies.ok_or(DecoderError::Custom("No bodies cost specified"))),
-			receipts: try!(receipts.ok_or(DecoderError::Custom("No receipts cost specified"))),
-			state_proofs: try!(state_proofs.ok_or(DecoderError::Custom("No proofs cost specified"))),
-			contract_codes: try!(contract_codes.ok_or(DecoderError::Custom("No contract codes specified"))),
-			header_proofs: try!(header_proofs.ok_or(DecoderError::Custom("No header proofs cost specified"))),
+			headers: headers.ok_or(DecoderError::Custom("No headers cost specified"))?,
+			bodies: bodies.ok_or(DecoderError::Custom("No bodies cost specified"))?,
+			receipts: receipts.ok_or(DecoderError::Custom("No receipts cost specified"))?,
+			state_proofs: state_proofs.ok_or(DecoderError::Custom("No proofs cost specified"))?,
+			contract_codes: contract_codes.ok_or(DecoderError::Custom("No contract codes specified"))?,
+			header_proofs: header_proofs.ok_or(DecoderError::Custom("No header proofs cost specified"))?,
 		})
 	}
 }

ethcore/light/src/net/mod.rs

@@ -143,7 +143,7 @@ impl Peer {
 		flow_params.recharge(&mut self.local_buffer);
 
 		let max_cost = flow_params.compute_cost(kind, max);
-		try!(self.local_buffer.deduct_cost(max_cost));
+		self.local_buffer.deduct_cost(max_cost)?;
 		Ok(max_cost)
 	}
 
@@ -275,14 +275,14 @@ impl LightProtocol {
 	/// with an event.
 	pub fn request_from(&self, io: &IoContext, peer_id: &PeerId, request: Request) -> Result<ReqId, Error> {
 		let peers = self.peers.read();
-		let peer = try!(peers.get(peer_id).ok_or_else(|| Error::UnknownPeer));
+		let peer = peers.get(peer_id).ok_or_else(|| Error::UnknownPeer)?;
 		let mut peer = peer.lock();
 
 		match peer.remote_flow.as_mut() {
 			Some(&mut (ref mut buf, ref flow)) => {
 				flow.recharge(buf);
 				let max = flow.compute_cost(request.kind(), request.amount());
-				try!(buf.deduct_cost(max));
+				buf.deduct_cost(max)?;
 			}
 			None => return Err(Error::NotServer),
 		}
@@ -386,8 +386,8 @@ impl LightProtocol {
 	//   - check whether request was made
 	//   - check whether request kinds match
 	fn pre_verify_response(&self, peer: &PeerId, kind: request::Kind, raw: &UntrustedRlp) -> Result<ReqId, Error> {
-		let req_id: usize = try!(raw.val_at(0));
-		let cur_buffer: U256 = try!(raw.val_at(1));
+		let req_id: usize = raw.val_at(0)?;
+		let cur_buffer: U256 = raw.val_at(1)?;
 
 		trace!(target: "les", "pre-verifying response from peer {}, kind={:?}", peer, kind);
 
@@ -582,7 +582,7 @@ impl LightProtocol {
 			}
 		};
 
-		let (status, capabilities, flow_params) = try!(status::parse_handshake(data));
+		let (status, capabilities, flow_params) = status::parse_handshake(data)?;
 
 		trace!(target: "les", "Connected peer with chain head {:?}", (status.head_hash, status.head_num));
 
@@ -623,7 +623,7 @@ impl LightProtocol {
 			return Ok(())
 		}
 
-		let announcement = try!(status::parse_announcement(data));
+		let announcement = status::parse_announcement(data)?;
 
 		// scope to ensure locks are dropped before moving into handler-space.
 		{
@@ -676,25 +676,25 @@ impl LightProtocol {
 
 		let mut peer = peer.lock();
 
-		let req_id: u64 = try!(data.val_at(0));
-		let data = try!(data.at(1));
+		let req_id: u64 = data.val_at(0)?;
+		let data = data.at(1)?;
 
 		let start_block = {
-			if try!(data.at(0)).size() == 32 {
-				HashOrNumber::Hash(try!(data.val_at(0)))
+			if data.at(0)?.size() == 32 {
+				HashOrNumber::Hash(data.val_at(0)?)
 			} else {
-				HashOrNumber::Number(try!(data.val_at(0)))
+				HashOrNumber::Number(data.val_at(0)?)
 			}
 		};
 
 		let req = request::Headers {
 			start: start_block,
-			max: ::std::cmp::min(MAX_HEADERS, try!(data.val_at(1))),
-			skip: try!(data.val_at(2)),
-			reverse: try!(data.val_at(3)),
+			max: ::std::cmp::min(MAX_HEADERS, data.val_at(1)?),
+			skip: data.val_at(2)?,
+			reverse: data.val_at(3)?,
 		};
 
-		let max_cost = try!(peer.deduct_max(&self.flow_params, request::Kind::Headers, req.max));
+		let max_cost = peer.deduct_max(&self.flow_params, request::Kind::Headers, req.max)?;
 
 		let response = self.provider.block_headers(req);
 		let actual_cost = self.flow_params.compute_cost(request::Kind::Headers, response.len());
@@ -717,8 +717,8 @@ impl LightProtocol {
 
 	// Receive a response for block headers.
 	fn block_headers(&self, peer: &PeerId, io: &IoContext, raw: UntrustedRlp) -> Result<(), Error> {
-		let req_id = try!(self.pre_verify_response(peer, request::Kind::Headers, &raw));
-		let raw_headers: Vec<_> = try!(raw.at(2)).iter().map(|x| x.as_raw().to_owned()).collect();
+		let req_id = self.pre_verify_response(peer, request::Kind::Headers, &raw)?;
+		let raw_headers: Vec<_> = raw.at(2)?.iter().map(|x| x.as_raw().to_owned()).collect();
 
 		for handler in &self.handlers {
 			handler.on_block_headers(&Ctx {
@@ -745,13 +745,16 @@ impl LightProtocol {
 		};
 		let mut peer = peer.lock();
 
-		let req_id: u64 = try!(data.val_at(0));
+		let req_id: u64 = data.val_at(0)?;
 
 		let req = request::Bodies {
-			block_hashes: try!(try!(data.at(1)).iter().take(MAX_BODIES).map(|x| x.as_val()).collect())
+			block_hashes: data.at(1)?.iter()
+				.take(MAX_BODIES)
+				.map(|x| x.as_val())
+				.collect::<Result<_, _>>()?
 		};
 
-		let max_cost = try!(peer.deduct_max(&self.flow_params, request::Kind::Bodies, req.block_hashes.len()));
+		let max_cost = peer.deduct_max(&self.flow_params, request::Kind::Bodies, req.block_hashes.len())?;
 
 		let response = self.provider.block_bodies(req);
 		let response_len = response.iter().filter(|x| &x[..] != &::rlp::EMPTY_LIST_RLP).count();
@@ -776,8 +779,8 @@ impl LightProtocol {
 
 	// Receive a response for block bodies.
 	fn block_bodies(&self, peer: &PeerId, io: &IoContext, raw: UntrustedRlp) -> Result<(), Error> {
-		let req_id = try!(self.pre_verify_response(peer, request::Kind::Bodies, &raw));
-		let raw_bodies: Vec<Bytes> = try!(raw.at(2)).iter().map(|x| x.as_raw().to_owned()).collect();
+		let req_id = self.pre_verify_response(peer, request::Kind::Bodies, &raw)?;
+		let raw_bodies: Vec<Bytes> = raw.at(2)?.iter().map(|x| x.as_raw().to_owned()).collect();
 
 		for handler in &self.handlers {
 			handler.on_block_bodies(&Ctx {
@@ -804,13 +807,16 @@ impl LightProtocol {
 		};
 		let mut peer = peer.lock();
 
-		let req_id: u64 = try!(data.val_at(0));
+		let req_id: u64 = data.val_at(0)?;
 
 		let req = request::Receipts {
-			block_hashes: try!(try!(data.at(1)).iter().take(MAX_RECEIPTS).map(|x| x.as_val()).collect())
+			block_hashes: data.at(1)?.iter()
+				.take(MAX_RECEIPTS)
+				.map(|x| x.as_val())
+				.collect::<Result<_,_>>()?
 		};
 
-		let max_cost = try!(peer.deduct_max(&self.flow_params, request::Kind::Receipts, req.block_hashes.len()));
+		let max_cost = peer.deduct_max(&self.flow_params, request::Kind::Receipts, req.block_hashes.len())?;
 
 		let response = self.provider.receipts(req);
 		let response_len = response.iter().filter(|x| &x[..] != &::rlp::EMPTY_LIST_RLP).count();
@@ -835,11 +841,11 @@ impl LightProtocol {
 
 	// Receive a response for receipts.
 	fn receipts(&self, peer: &PeerId, io: &IoContext, raw: UntrustedRlp) -> Result<(), Error> {
-		let req_id = try!(self.pre_verify_response(peer, request::Kind::Receipts, &raw));
-		let raw_receipts: Vec<Vec<Receipt>> = try!(try!(raw.at(2))
+		let req_id = self.pre_verify_response(peer, request::Kind::Receipts, &raw)?;
+		let raw_receipts: Vec<Vec<Receipt>> = raw.at(2)?
 			.iter()
 			.map(|x| x.as_val())
-			.collect());
+			.collect::<Result<_,_>>()?;
 
 		for handler in &self.handlers {
 			handler.on_receipts(&Ctx {
@@ -866,24 +872,24 @@ impl LightProtocol {
 		};
 		let mut peer = peer.lock();
 
-		let req_id: u64 = try!(data.val_at(0));
+		let req_id: u64 = data.val_at(0)?;
 
 		let req = {
-			let requests: Result<Vec<_>, Error> = try!(data.at(1)).iter().take(MAX_PROOFS).map(|x| {
+			let requests: Result<Vec<_>, Error> = data.at(1)?.iter().take(MAX_PROOFS).map(|x| {
 				Ok(request::StateProof {
-					block: try!(x.val_at(0)),
-					key1: try!(x.val_at(1)),
-					key2: if try!(x.at(2)).is_empty() { None } else { Some(try!(x.val_at(2))) },
-					from_level: try!(x.val_at(3)),
+					block: x.val_at(0)?,
+					key1: x.val_at(1)?,
+					key2: if x.at(2)?.is_empty() { None } else { Some(x.val_at(2)?) },
+					from_level: x.val_at(3)?,
 				})
 			}).collect();
 
 			request::StateProofs {
-				requests: try!(requests),
+				requests: requests?,
 			}
 		};
 
-		let max_cost = try!(peer.deduct_max(&self.flow_params, request::Kind::StateProofs, req.requests.len()));
+		let max_cost = peer.deduct_max(&self.flow_params, request::Kind::StateProofs, req.requests.len())?;
 
 		let response = self.provider.proofs(req);
 		let response_len = response.iter().filter(|x| &x[..] != &::rlp::EMPTY_LIST_RLP).count();
@@ -908,9 +914,9 @@ impl LightProtocol {
 
 	// Receive a response for proofs.
 	fn proofs(&self, peer: &PeerId, io: &IoContext, raw: UntrustedRlp) -> Result<(), Error> {
-		let req_id = try!(self.pre_verify_response(peer, request::Kind::StateProofs, &raw));
+		let req_id = self.pre_verify_response(peer, request::Kind::StateProofs, &raw)?;
 
-		let raw_proofs: Vec<Vec<Bytes>> = try!(raw.at(2)).iter()
+		let raw_proofs: Vec<Vec<Bytes>> = raw.at(2)?.iter()
 			.map(|x| x.iter().map(|node| node.as_raw().to_owned()).collect())
 			.collect();
 
@@ -939,22 +945,22 @@ impl LightProtocol {
 		};
 		let mut peer = peer.lock();
 
-		let req_id: u64 = try!(data.val_at(0));
+		let req_id: u64 = data.val_at(0)?;
 
 		let req = {
-			let requests: Result<Vec<_>, Error> = try!(data.at(1)).iter().take(MAX_CODES).map(|x| {
+			let requests: Result<Vec<_>, Error> = data.at(1)?.iter().take(MAX_CODES).map(|x| {
 				Ok(request::ContractCode {
-					block_hash: try!(x.val_at(0)),
-					account_key: try!(x.val_at(1)),
+					block_hash: x.val_at(0)?,
+					account_key: x.val_at(1)?,
 				})
 			}).collect();
 
 			request::ContractCodes {
-				code_requests: try!(requests),
+				code_requests: requests?,
 			}
 		};
 
-		let max_cost = try!(peer.deduct_max(&self.flow_params, request::Kind::Codes, req.code_requests.len()));
+		let max_cost = peer.deduct_max(&self.flow_params, request::Kind::Codes, req.code_requests.len())?;
 
 		let response = self.provider.contract_codes(req);
 		let response_len = response.iter().filter(|x| !x.is_empty()).count();
@@ -979,9 +985,11 @@ impl LightProtocol {
 
 	// Receive a response for contract code.
 	fn contract_code(&self, peer: &PeerId, io: &IoContext, raw: UntrustedRlp) -> Result<(), Error> {
-		let req_id = try!(self.pre_verify_response(peer, request::Kind::Codes, &raw));
+		let req_id = self.pre_verify_response(peer, request::Kind::Codes, &raw)?;
 
-		let raw_code: Vec<Bytes> = try!(try!(raw.at(2)).iter().map(|x| x.as_val()).collect());
+		let raw_code: Vec<Bytes> = raw.at(2)?.iter()
+			.map(|x| x.as_val())
+			.collect::<Result<_,_>>()?;
 
 		for handler in &self.handlers {
 			handler.on_code(&Ctx {
@@ -1008,23 +1016,23 @@ impl LightProtocol {
 		};
 		let mut peer = peer.lock();
 
-		let req_id: u64 = try!(data.val_at(0));
+		let req_id: u64 = data.val_at(0)?;
 
 		let req = {
-			let requests: Result<Vec<_>, Error> = try!(data.at(1)).iter().take(MAX_PROOFS).map(|x| {
+			let requests: Result<Vec<_>, Error> = data.at(1)?.iter().take(MAX_PROOFS).map(|x| {
 				Ok(request::HeaderProof {
-					cht_number: try!(x.val_at(0)),
-					block_number: try!(x.val_at(1)),
-					from_level: try!(x.val_at(2)),
+					cht_number: x.val_at(0)?,
+					block_number: x.val_at(1)?,
+					from_level: x.val_at(2)?,
 				})
 			}).collect();
 
 			request::HeaderProofs {
-				requests: try!(requests),
+				requests: requests?,
 			}
 		};
 
-		let max_cost = try!(peer.deduct_max(&self.flow_params, request::Kind::HeaderProofs, req.requests.len()));
+		let max_cost = peer.deduct_max(&self.flow_params, request::Kind::HeaderProofs, req.requests.len())?;
 
 		let response = self.provider.header_proofs(req);
 		let response_len = response.iter().filter(|x| &x[..] != ::rlp::EMPTY_LIST_RLP).count();
@@ -1051,13 +1059,15 @@ impl LightProtocol {
 	fn header_proofs(&self, peer: &PeerId, io: &IoContext, raw: UntrustedRlp) -> Result<(), Error> {
 		fn decode_res(raw: UntrustedRlp) -> Result<(Bytes, Vec<Bytes>), ::rlp::DecoderError> {
 			Ok((
-				try!(raw.val_at(0)),
-				try!(raw.at(1)).iter().map(|x| x.as_raw().to_owned()).collect(),
+				raw.val_at(0)?,
+				raw.at(1)?.iter().map(|x| x.as_raw().to_owned()).collect(),
 			))
 		}
 
-		let req_id = try!(self.pre_verify_response(peer, request::Kind::HeaderProofs, &raw));
-		let raw_proofs: Vec<_> = try!(try!(raw.at(2)).iter().map(decode_res).collect());
+		let req_id = self.pre_verify_response(peer, request::Kind::HeaderProofs, &raw)?;
+		let raw_proofs: Vec<_> = raw.at(2)?.iter()
+			.map(decode_res)
+			.collect::<Result<_,_>>()?;
 
 		for handler in &self.handlers {
 			handler.on_header_proofs(&Ctx {
@@ -1074,7 +1084,10 @@ impl LightProtocol {
 	fn relay_transactions(&self, peer: &PeerId, io: &IoContext, data: UntrustedRlp) -> Result<(), Error> {
 		const MAX_TRANSACTIONS: usize = 256;
 
-		let txs: Vec<_> = try!(data.iter().take(MAX_TRANSACTIONS).map(|x| x.as_val::<SignedTransaction>()).collect());
+		let txs: Vec<_> = data.iter()
+			.take(MAX_TRANSACTIONS)
+			.map(|x| x.as_val::<SignedTransaction>())
+			.collect::<Result<_,_>>()?;
 
 		debug!(target: "les", "Received {} transactions to relay from peer {}", txs.len(), peer);
 

ethcore/light/src/net/status.rs

@@ -100,7 +100,7 @@ impl<'a> Parser<'a> {
 	fn expect_raw(&mut self, key: Key) -> Result<UntrustedRlp<'a>, DecoderError> {
 		trace!(target: "les", "Expecting key {}", key.as_str());
 		let pre_pos = self.pos;
-		if let Some((k, val)) = try!(self.get_next()) {
+		if let Some((k, val)) = self.get_next()? {
 			if k == key { return Ok(val) }
 		}
 
@@ -111,12 +111,12 @@ impl<'a> Parser<'a> {
 	// get the next key and value RLP.
 	fn get_next(&mut self) -> Result<Option<(Key, UntrustedRlp<'a>)>, DecoderError> {
 		while self.pos < self.rlp.item_count() {
-			let pair = try!(self.rlp.at(self.pos));
-			let k: String = try!(pair.val_at(0));
+			let pair = self.rlp.at(self.pos)?;
+			let k: String = pair.val_at(0)?;
 
 			self.pos += 1;
 			match Key::from_str(&k) {
-				Some(key) => return Ok(Some((key , try!(pair.at(1))))),
+				Some(key) => return Ok(Some((key , pair.at(1)?))),
 				None => continue,
 			}
 		}
@@ -205,12 +205,12 @@ pub fn parse_handshake(rlp: UntrustedRlp) -> Result<(Status, Capabilities, Optio
 	};
 
 	let status = Status {
-		protocol_version: try!(parser.expect(Key::ProtocolVersion)),
-		network_id: try!(parser.expect(Key::NetworkId)),
-		head_td: try!(parser.expect(Key::HeadTD)),
-		head_hash: try!(parser.expect(Key::HeadHash)),
-		head_num: try!(parser.expect(Key::HeadNum)),
-		genesis_hash: try!(parser.expect(Key::GenesisHash)),
+		protocol_version: parser.expect(Key::ProtocolVersion)?,
+		network_id: parser.expect(Key::NetworkId)?,
+		head_td: parser.expect(Key::HeadTD)?,
+		head_hash: parser.expect(Key::HeadHash)?,
+		head_num: parser.expect(Key::HeadNum)?,
+		genesis_hash: parser.expect(Key::GenesisHash)?,
 		last_head: None,
 	};
 
@@ -298,10 +298,10 @@ pub fn parse_announcement(rlp: UntrustedRlp) -> Result<Announcement, DecoderErro
 	let mut last_key = None;
 
 	let mut announcement = Announcement {
-		head_hash: try!(rlp.val_at(0)),
-		head_num: try!(rlp.val_at(1)),
-		head_td: try!(rlp.val_at(2)),
-		reorg_depth: try!(rlp.val_at(3)),
+		head_hash: rlp.val_at(0)?,
+		head_num: rlp.val_at(1)?,
+		head_td: rlp.val_at(2)?,
+		reorg_depth: rlp.val_at(3)?,
 		serve_headers: false,
 		serve_state_since: None,
 		serve_chain_since: None,
@@ -313,14 +313,14 @@ pub fn parse_announcement(rlp: UntrustedRlp) -> Result<Announcement, DecoderErro
 		rlp: rlp,
 	};
 
-	while let Some((key, item)) = try!(parser.get_next()) {
+	while let Some((key, item)) = parser.get_next()? {
 		if Some(key) <= last_key { return Err(DecoderError::Custom("Invalid announcement key ordering")) }
 		last_key = Some(key);
 
 		match key {
 			Key::ServeHeaders => announcement.serve_headers = true,
-			Key::ServeStateSince => announcement.serve_state_since = Some(try!(item.as_val())),
-			Key::ServeChainSince => announcement.serve_chain_since = Some(try!(item.as_val())),
+			Key::ServeStateSince => announcement.serve_state_since = Some(item.as_val()?),
+			Key::ServeChainSince => announcement.serve_chain_since = Some(item.as_val()?),
 			Key::TxRelay => announcement.tx_relay = true,
 			_ => return Err(DecoderError::Custom("Nonsensical key in announcement")),
 		}

ethcore/src/account_provider/mod.rs

@@ -127,32 +127,32 @@ impl AccountProvider {
 		let acc = Random.generate().expect("secp context has generation capabilities; qed");
 		let public = acc.public().clone();
 		let secret = acc.secret().clone();
-		let address = try!(self.sstore.insert_account(secret, password));
+		let address = self.sstore.insert_account(secret, password)?;
 		Ok((address, public))
 	}
 
 	/// Inserts new account into underlying store.
 	/// Does not unlock account!
 	pub fn insert_account(&self, secret: Secret, password: &str) -> Result<Address, Error> {
-		let address = try!(self.sstore.insert_account(secret, password));
+		let address = self.sstore.insert_account(secret, password)?;
 		Ok(address)
 	}
 
 	/// Import a new presale wallet.
 	pub fn import_presale(&self, presale_json: &[u8], password: &str) -> Result<Address, Error> {
-		let address = try!(self.sstore.import_presale(presale_json, password));
+		let address = self.sstore.import_presale(presale_json, password)?;
 		Ok(Address::from(address).into())
 	}
 
 	/// Import a new presale wallet.
 	pub fn import_wallet(&self, json: &[u8], password: &str) -> Result<Address, Error> {
-		let address = try!(self.sstore.import_wallet(json, password));
+		let address = self.sstore.import_wallet(json, password)?;
 		Ok(Address::from(address).into())
 	}
 
 	/// Returns addresses of all accounts.
 	pub fn accounts(&self) -> Result<Vec<Address>, Error> {
-		let accounts = try!(self.sstore.accounts());
+		let accounts = self.sstore.accounts()?;
 		Ok(accounts)
 	}
 
@@ -229,7 +229,7 @@ impl AccountProvider {
 
 	/// Returns each account along with name and meta.
 	pub fn accounts_info(&self) -> Result<HashMap<Address, AccountMeta>, Error> {
-		let r: HashMap<Address, AccountMeta> = try!(self.sstore.accounts())
+		let r: HashMap<Address, AccountMeta> = self.sstore.accounts()?
 			.into_iter()
 			.map(|a| (a.clone(), self.account_meta(a).ok().unwrap_or_default()))
 			.collect();
@@ -239,21 +239,21 @@ impl AccountProvider {
 	/// Returns each account along with name and meta.
 	pub fn account_meta(&self, account: Address) -> Result<AccountMeta, Error> {
 		Ok(AccountMeta {
-			name: try!(self.sstore.name(&account)),
-			meta: try!(self.sstore.meta(&account)),
+			name: self.sstore.name(&account)?,
+			meta: self.sstore.meta(&account)?,
 			uuid: self.sstore.uuid(&account).ok().map(Into::into),	// allowed to not have a Uuid
 		})
 	}
 
 	/// Returns each account along with name and meta.
 	pub fn set_account_name(&self, account: Address, name: String) -> Result<(), Error> {
-		try!(self.sstore.set_name(&account, name));
+		self.sstore.set_name(&account, name)?;
 		Ok(())
 	}
 
 	/// Returns each account along with name and meta.
 	pub fn set_account_meta(&self, account: Address, meta: String) -> Result<(), Error> {
-		try!(self.sstore.set_meta(&account, meta));
+		self.sstore.set_meta(&account, meta)?;
 		Ok(())
 	}
 
@@ -265,7 +265,7 @@ impl AccountProvider {
 
 	/// Permanently removes an account.
 	pub fn kill_account(&self, account: &Address, password: &str) -> Result<(), Error> {
-		try!(self.sstore.remove_account(account, &password));
+		self.sstore.remove_account(account, &password)?;
 		Ok(())
 	}
 
@@ -278,7 +278,7 @@ impl AccountProvider {
 	fn unlock_account(&self, account: Address, password: String, unlock: Unlock) -> Result<(), Error> {
 		// verify password by signing dump message
 		// result may be discarded
-		let _ = try!(self.sstore.sign(&account, &password, &Default::default()));
+		let _ = self.sstore.sign(&account, &password, &Default::default())?;
 
 		// check if account is already unlocked pernamently, if it is, do nothing
 		let mut unlocked = self.unlocked.write();
@@ -299,7 +299,7 @@ impl AccountProvider {
 
 	fn password(&self, account: &Address) -> Result<String, Error> {
 		let mut unlocked = self.unlocked.write();
-		let data = try!(unlocked.get(account).ok_or(Error::NotUnlocked)).clone();
+		let data = unlocked.get(account).ok_or(Error::NotUnlocked)?.clone();
 		if let Unlock::Temp = data.unlock {
 			unlocked.remove(account).expect("data exists: so key must exist: qed");
 		}
@@ -335,25 +335,25 @@ impl AccountProvider {
 
 	/// Signs the message. If password is not provided the account must be unlocked.
 	pub fn sign(&self, account: Address, password: Option<String>, message: Message) -> Result<Signature, Error> {
-		let password = try!(password.map(Ok).unwrap_or_else(|| self.password(&account)));
-		Ok(try!(self.sstore.sign(&account, &password, &message)))
+		let password = password.map(Ok).unwrap_or_else(|| self.password(&account))?;
+		Ok(self.sstore.sign(&account, &password, &message)?)
 	}
 
 	/// Signs given message with supplied token. Returns a token to use in next signing within this session.
 	pub fn sign_with_token(&self, account: Address, token: AccountToken, message: Message) -> Result<(Signature, AccountToken), Error> {
-		let is_std_password = try!(self.sstore.test_password(&account, &token));
+		let is_std_password = self.sstore.test_password(&account, &token)?;
 
 		let new_token = random_string(16);
 		let signature = if is_std_password {
 			// Insert to transient store
-			try!(self.sstore.copy_account(&self.transient_sstore, &account, &token, &new_token));
+			self.sstore.copy_account(&self.transient_sstore, &account, &token, &new_token)?;
 			// sign
-			try!(self.sstore.sign(&account, &token, &message))
+			self.sstore.sign(&account, &token, &message)?
 		} else {
 			// check transient store
-			try!(self.transient_sstore.change_password(&account, &token, &new_token));
+			self.transient_sstore.change_password(&account, &token, &new_token)?;
 			// and sign
-			try!(self.transient_sstore.sign(&account, &new_token, &message))
+			self.transient_sstore.sign(&account, &new_token, &message)?
 		};
 
 		Ok((signature, new_token))
@@ -363,19 +363,19 @@ impl AccountProvider {
 	pub fn decrypt_with_token(&self, account: Address, token: AccountToken, shared_mac: &[u8], message: &[u8])
 		-> Result<(Vec<u8>, AccountToken), Error>
 	{
-		let is_std_password = try!(self.sstore.test_password(&account, &token));
+		let is_std_password = self.sstore.test_password(&account, &token)?;
 
 		let new_token = random_string(16);
 		let message = if is_std_password {
 			// Insert to transient store
-			try!(self.sstore.copy_account(&self.transient_sstore, &account, &token, &new_token));
+			self.sstore.copy_account(&self.transient_sstore, &account, &token, &new_token)?;
 			// decrypt
-			try!(self.sstore.decrypt(&account, &token, shared_mac, message))
+			self.sstore.decrypt(&account, &token, shared_mac, message)?
 		} else {
 			// check transient store
-			try!(self.transient_sstore.change_password(&account, &token, &new_token));
+			self.transient_sstore.change_password(&account, &token, &new_token)?;
 			// and decrypt
-			try!(self.transient_sstore.decrypt(&account, &token, shared_mac, message))
+			self.transient_sstore.decrypt(&account, &token, shared_mac, message)?
 		};
 
 		Ok((message, new_token))
@@ -383,8 +383,8 @@ impl AccountProvider {
 
 	/// Decrypts a message. If password is not provided the account must be unlocked.
 	pub fn decrypt(&self, account: Address, password: Option<String>, shared_mac: &[u8], message: &[u8]) -> Result<Vec<u8>, Error> {
-		let password = try!(password.map(Ok).unwrap_or_else(|| self.password(&account)));
-		Ok(try!(self.sstore.decrypt(&account, &password, shared_mac, message)))
+		let password = password.map(Ok).unwrap_or_else(|| self.password(&account))?;
+		Ok(self.sstore.decrypt(&account, &password, shared_mac, message)?)
 	}
 
 	/// Returns the underlying `SecretStore` reference if one exists.

ethcore/src/block.rs

@@ -67,7 +67,7 @@ impl Block {
 
 impl Decodable for Block {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
-		if decoder.as_raw().len() != try!(decoder.as_rlp().payload_info()).total() {
+		if decoder.as_raw().len() != decoder.as_rlp().payload_info()?.total() {
 			return Err(DecoderError::RlpIsTooBig);
 		}
 		let d = decoder.as_rlp();
@@ -75,9 +75,9 @@ impl Decodable for Block {
 			return Err(DecoderError::RlpIncorrectListLen);
 		}
 		Ok(Block {
-			header: try!(d.val_at(0)),
-			transactions: try!(d.val_at(1)),
-			uncles: try!(d.val_at(2)),
+			header: d.val_at(0)?,
+			transactions: d.val_at(1)?,
+			uncles: d.val_at(2)?,
 		})
 	}
 }
@@ -252,7 +252,7 @@ impl<'x> OpenBlock<'x> {
 		gas_range_target: (U256, U256),
 		extra_data: Bytes,
 	) -> Result<Self, Error> {
-		let state = try!(State::from_existing(db, parent.state_root().clone(), engine.account_start_nonce(), factories));
+		let state = State::from_existing(db, parent.state_root().clone(), engine.account_start_nonce(), factories)?;
 		let mut r = OpenBlock {
 			block: ExecutedBlock::new(state, tracing),
 			engine: engine,
@@ -521,12 +521,12 @@ pub fn enact(
 ) -> Result<LockedBlock, Error> {
 	{
 		if ::log::max_log_level() >= ::log::LogLevel::Trace {
-			let s = try!(State::from_existing(db.boxed_clone(), parent.state_root().clone(), engine.account_start_nonce(), factories.clone()));
+			let s = State::from_existing(db.boxed_clone(), parent.state_root().clone(), engine.account_start_nonce(), factories.clone())?;
 			trace!(target: "enact", "num={}, root={}, author={}, author_balance={}\n", header.number(), s.root(), header.author(), s.balance(&header.author()));
 		}
 	}
 
-	let mut b = try!(OpenBlock::new(engine, factories, tracing, db, parent, last_hashes, Address::new(), (3141562.into(), 31415620.into()), vec![]));
+	let mut b = OpenBlock::new(engine, factories, tracing, db, parent, last_hashes, Address::new(), (3141562.into(), 31415620.into()), vec![])?;
 	b.set_difficulty(*header.difficulty());
 	b.set_gas_limit(*header.gas_limit());
 	b.set_timestamp(header.timestamp());
@@ -536,9 +536,9 @@ pub fn enact(
 	b.set_transactions_root(header.transactions_root().clone());
 	b.set_receipts_root(header.receipts_root().clone());
 
-	try!(push_transactions(&mut b, transactions));
+	push_transactions(&mut b, transactions)?;
 	for u in uncles {
-		try!(b.push_uncle(u.clone()));
+		b.push_uncle(u.clone())?;
 	}
 	Ok(b.close_and_lock())
 }
@@ -547,7 +547,7 @@ pub fn enact(
 #[cfg(not(feature = "slow-blocks"))]
 fn push_transactions(block: &mut OpenBlock, transactions: &[SignedTransaction]) -> Result<(), Error> {
 	for t in transactions {
-		try!(block.push_transaction(t.clone(), None));
+		block.push_transaction(t.clone(), None)?;
 	}
 	Ok(())
 }
@@ -560,7 +560,7 @@ fn push_transactions(block: &mut OpenBlock, transactions: &[SignedTransaction])
 	for t in transactions {
 		let hash = t.hash();
 		let start = time::Instant::now();
-		try!(block.push_transaction(t.clone(), None));
+		block.push_transaction(t.clone(), None)?;
 		let took = start.elapsed();
 		if took > time::Duration::from_millis(slow_tx) {
 			warn!("Heavy transaction in block {:?}: {:?}", block.header().number(), hash);
@@ -627,7 +627,7 @@ mod tests {
 		factories: Factories,
 	) -> Result<SealedBlock, Error> {
 		let header = BlockView::new(block_bytes).header_view();
-		Ok(try!(try!(enact_bytes(block_bytes, engine, tracing, db, parent, last_hashes, factories)).seal(engine, header.seal())))
+		Ok(enact_bytes(block_bytes, engine, tracing, db, parent, last_hashes, factories)?.seal(engine, header.seal())?)
 	}
 
 	#[test]

ethcore/src/blockchain/extras.rs

@@ -157,10 +157,10 @@ impl Decodable for BlockDetails {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		let details = BlockDetails {
-			number: try!(d.val_at(0)),
-			total_difficulty: try!(d.val_at(1)),
-			parent: try!(d.val_at(2)),
-			children: try!(d.val_at(3)),
+			number: d.val_at(0)?,
+			total_difficulty: d.val_at(1)?,
+			parent: d.val_at(2)?,
+			children: d.val_at(3)?,
 		};
 		Ok(details)
 	}
@@ -193,8 +193,8 @@ impl Decodable for TransactionAddress {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		let tx_address = TransactionAddress {
-			block_hash: try!(d.val_at(0)),
-			index: try!(d.val_at(1)),
+			block_hash: d.val_at(0)?,
+			index: d.val_at(1)?,
 		};
 
 		Ok(tx_address)
@@ -226,7 +226,7 @@ impl BlockReceipts {
 impl Decodable for BlockReceipts {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		Ok(BlockReceipts {
-			receipts: try!(Decodable::decode(decoder))
+			receipts: Decodable::decode(decoder)?
 		})
 	}
 }

ethcore/src/blooms/bloom_group.rs

@@ -53,7 +53,7 @@ impl Into<bc::BloomGroup> for BloomGroup {
 
 impl Decodable for BloomGroup {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
-		let blooms = try!(Decodable::decode(decoder));
+		let blooms = Decodable::decode(decoder)?;
 		let group = BloomGroup {
 			blooms: blooms
 		};

ethcore/src/client/client.rs

@@ -167,7 +167,7 @@ impl Client {
 	) -> Result<Arc<Client>, ClientError> {
 
 		let path = path.to_path_buf();
-		let db = Arc::new(try!(Database::open(&db_config, &path.to_str().expect("DB path could not be converted to string.")).map_err(ClientError::Database)));
+		let db = Arc::new(Database::open(&db_config, &path.to_str().expect("DB path could not be converted to string.")).map_err(ClientError::Database)?);
 		let trie_spec = match config.fat_db {
 			true => TrieSpec::Fat,
 			false => TrieSpec::Secure,
@@ -186,8 +186,8 @@ impl Client {
 			// Sets the correct state root.
 			state_db = spec.ensure_db_good(state_db, &factories)?;
 			let mut batch = DBTransaction::new(&db);
-			try!(state_db.journal_under(&mut batch, 0, &spec.genesis_header().hash()));
-			try!(db.write(batch).map_err(ClientError::Database));
+			state_db.journal_under(&mut batch, 0, &spec.genesis_header().hash())?;
+			db.write(batch).map_err(ClientError::Database)?;
 		}
 
 		let gb = spec.genesis_block();
@@ -210,8 +210,8 @@ impl Client {
 				for era in earliest..(latest - history + 1) {
 					trace!("Removing era {}", era);
 					let mut batch = DBTransaction::new(&db);
-					try!(state_db.mark_canonical(&mut batch, era, &chain.block_hash(era).expect("Old block not found in the database")));
-					try!(db.write(batch).map_err(ClientError::Database));
+					state_db.mark_canonical(&mut batch, era, &chain.block_hash(era).expect("Old block not found in the database"))?;
+					db.write(batch).map_err(ClientError::Database)?;
 				}
 			}
 		}
@@ -252,7 +252,7 @@ impl Client {
 			last_hashes: RwLock::new(VecDeque::new()),
 			factories: factories,
 			history: history,
-			rng: Mutex::new(try!(OsRng::new().map_err(::util::UtilError::StdIo))),
+			rng: Mutex::new(OsRng::new().map_err(::util::UtilError::StdIo)?),
 			on_mode_change: Mutex::new(None),
 			registrar: Mutex::new(None),
 		});
@@ -370,9 +370,9 @@ impl Client {
 			let db = self.state_db.lock().boxed_clone_canon(header.parent_hash());
 
 			let enact_result = enact_verified(block, engine, self.tracedb.read().tracing_enabled(), db, &parent, last_hashes, self.factories.clone());
-			let locked_block = try!(enact_result.map_err(|e| {
+			let locked_block = enact_result.map_err(|e| {
 				warn!(target: "client", "Block import failed for #{} ({})\nError: {:?}", header.number(), header.hash(), e);
-			}));
+			})?;
 
 			// Final Verification
 			if let Err(e) = self.verifier.verify_block_final(header, locked_block.block().header()) {
@@ -511,14 +511,14 @@ impl Client {
 			let chain = self.chain.read();
 
 			// verify block.
-			try!(::snapshot::verify_old_block(
+			::snapshot::verify_old_block(
 				&mut *rng,
 				&header,
 				&*self.engine,
 				&*chain,
 				Some(&block_bytes),
 				false,
-			));
+			)?;
 
 			// Commit results
 			let receipts = ::rlp::decode(&receipts_bytes);
@@ -739,7 +739,7 @@ impl Client {
 	pub fn take_snapshot<W: snapshot_io::SnapshotWriter + Send>(&self, writer: W, at: BlockId, p: &snapshot::Progress) -> Result<(), EthcoreError> {
 		let db = self.state_db.lock().journal_db().boxed_clone();
 		let best_block_number = self.chain_info().best_block_number;
-		let block_number = try!(self.block_number(at).ok_or(snapshot::Error::InvalidStartingBlock(at)));
+		let block_number = self.block_number(at).ok_or(snapshot::Error::InvalidStartingBlock(at))?;
 
 		if best_block_number > self.history + block_number && db.is_pruned() {
 			return Err(snapshot::Error::OldBlockPrunedDB.into());
@@ -765,7 +765,7 @@ impl Client {
 			},
 		};
 
-		try!(snapshot::take_snapshot(&self.chain.read(), start_hash, db.as_hashdb(), writer, p));
+		snapshot::take_snapshot(&self.chain.read(), start_hash, db.as_hashdb(), writer, p)?;
 
 		Ok(())
 	}
@@ -829,7 +829,7 @@ impl snapshot::DatabaseRestore for Client {
 		let mut tracedb = self.tracedb.write();
 		self.miner.clear();
 		let db = self.db.write();
-		try!(db.restore(new_db));
+		db.restore(new_db)?;
 
 		let cache_size = state_db.cache_size();
 		*state_db = StateDB::new(journaldb::new(db.clone(), self.pruning, ::db::COL_STATE), cache_size);
@@ -842,7 +842,7 @@ impl snapshot::DatabaseRestore for Client {
 
 impl BlockChainClient for Client {
 	fn call(&self, t: &SignedTransaction, block: BlockId, analytics: CallAnalytics) -> Result<Executed, CallError> {
-		let header = try!(self.block_header(block).ok_or(CallError::StatePruned));
+		let header = self.block_header(block).ok_or(CallError::StatePruned)?;
 		let view = HeaderView::new(&header);
 		let last_hashes = self.build_last_hashes(view.parent_hash());
 		let env_info = EnvInfo {
@@ -855,13 +855,13 @@ impl BlockChainClient for Client {
 			gas_limit: U256::max_value(),
 		};
 		// that's just a copy of the state.
-		let mut state = try!(self.state_at(block).ok_or(CallError::StatePruned));
+		let mut state = self.state_at(block).ok_or(CallError::StatePruned)?;
 		let original_state = if analytics.state_diffing { Some(state.clone()) } else { None };
 
-		let sender = try!(t.sender().map_err(|e| {
+		let sender = t.sender().map_err(|e| {
 			let message = format!("Transaction malformed: {:?}", e);
 			ExecutionError::TransactionMalformed(message)
-		}));
+		})?;
 		let balance = state.balance(&sender);
 		let needed_balance = t.value + t.gas * t.gas_price;
 		if balance < needed_balance {
@@ -869,7 +869,7 @@ impl BlockChainClient for Client {
 			state.add_balance(&sender, &(needed_balance - balance), CleanupMode::NoEmpty);
 		}
 		let options = TransactOptions { tracing: analytics.transaction_tracing, vm_tracing: analytics.vm_tracing, check_nonce: false };
-		let mut ret = try!(Executive::new(&mut state, &env_info, &*self.engine, &self.factories.vm).transact(t, options));
+		let mut ret = Executive::new(&mut state, &env_info, &*self.engine, &self.factories.vm).transact(t, options)?;
 
 		// TODO gav move this into Executive.
 		ret.state_diff = original_state.map(|original| state.diff_from(original));
@@ -878,10 +878,10 @@ impl BlockChainClient for Client {
 	}
 
 	fn replay(&self, id: TransactionId, analytics: CallAnalytics) -> Result<Executed, CallError> {
-		let address = try!(self.transaction_address(id).ok_or(CallError::TransactionNotFound));
-		let header_data = try!(self.block_header(BlockId::Hash(address.block_hash)).ok_or(CallError::StatePruned));
-		let body_data = try!(self.block_body(BlockId::Hash(address.block_hash)).ok_or(CallError::StatePruned));
-		let mut state = try!(self.state_at_beginning(BlockId::Hash(address.block_hash)).ok_or(CallError::StatePruned));
+		let address = self.transaction_address(id).ok_or(CallError::TransactionNotFound)?;
+		let header_data = self.block_header(BlockId::Hash(address.block_hash)).ok_or(CallError::StatePruned)?;
+		let body_data = self.block_body(BlockId::Hash(address.block_hash)).ok_or(CallError::StatePruned)?;
+		let mut state = self.state_at_beginning(BlockId::Hash(address.block_hash)).ok_or(CallError::StatePruned)?;
 		let txs = BodyView::new(&body_data).transactions();
 
 		if address.index >= txs.len() {
@@ -909,7 +909,7 @@ impl BlockChainClient for Client {
 		let t = &txs[address.index];
 
 		let original_state = if analytics.state_diffing { Some(state.clone()) } else { None };
-		let mut ret = try!(Executive::new(&mut state, &env_info, &*self.engine, &self.factories.vm).transact(t, options));
+		let mut ret = Executive::new(&mut state, &env_info, &*self.engine, &self.factories.vm).transact(t, options)?;
 		ret.state_diff = original_state.map(|original| state.diff_from(original));
 
 		Ok(ret)
@@ -1221,7 +1221,7 @@ impl BlockChainClient for Client {
 				return Err(BlockImportError::Block(BlockError::UnknownParent(unverified.parent_hash())));
 			}
 		}
-		Ok(try!(self.block_queue.import(unverified)))
+		Ok(self.block_queue.import(unverified)?)
 	}
 
 	fn import_block_with_receipts(&self, block_bytes: Bytes, receipts_bytes: Bytes) -> Result<H256, BlockImportError> {

ethcore/src/client/registry.rs

@@ -43,7 +43,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_bool().ok_or("Invalid type returned")); r })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_bool().ok_or("Invalid type returned")?; r })) 
 	}
 
 	/// Auto-generated from: `{"constant":false,"inputs":[{"name":"_name","type":"bytes32"}],"name":"reserve","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"}`
@@ -55,7 +55,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_bool().ok_or("Invalid type returned")); r })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_bool().ok_or("Invalid type returned")?; r })) 
 	}
 
 	/// Auto-generated from: `{"constant":false,"inputs":[{"name":"_name","type":"bytes32"},{"name":"_key","type":"string"},{"name":"_value","type":"bytes32"}],"name":"set","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"}`
@@ -67,7 +67,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_bool().ok_or("Invalid type returned")); r })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_bool().ok_or("Invalid type returned")?; r })) 
 	}
 
 	/// Auto-generated from: `{"constant":false,"inputs":[{"name":"_name","type":"bytes32"}],"name":"drop","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"}`
@@ -79,7 +79,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_bool().ok_or("Invalid type returned")); r })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_bool().ok_or("Invalid type returned")?; r })) 
 	}
 
 	/// Auto-generated from: `{"constant":true,"inputs":[{"name":"_name","type":"bytes32"},{"name":"_key","type":"string"}],"name":"getAddress","outputs":[{"name":"","type":"address"}],"payable":false,"type":"function"}`
@@ -91,7 +91,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_address().ok_or("Invalid type returned")); util::Address::from(r) })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_address().ok_or("Invalid type returned")?; util::Address::from(r) })) 
 	}
 
 	/// Auto-generated from: `{"constant":false,"inputs":[{"name":"_amount","type":"uint256"}],"name":"setFee","outputs":[],"payable":false,"type":"function"}`
@@ -115,7 +115,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_bool().ok_or("Invalid type returned")); r })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_bool().ok_or("Invalid type returned")?; r })) 
 	}
 
 	/// Auto-generated from: `{"constant":true,"inputs":[],"name":"owner","outputs":[{"name":"","type":"address"}],"payable":false,"type":"function"}`
@@ -127,7 +127,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_address().ok_or("Invalid type returned")); util::Address::from(r) })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_address().ok_or("Invalid type returned")?; util::Address::from(r) })) 
 	}
 
 	/// Auto-generated from: `{"constant":true,"inputs":[{"name":"_name","type":"bytes32"}],"name":"reserved","outputs":[{"name":"reserved","type":"bool"}],"payable":false,"type":"function"}`
@@ -139,7 +139,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_bool().ok_or("Invalid type returned")); r })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_bool().ok_or("Invalid type returned")?; r })) 
 	}
 
 	/// Auto-generated from: `{"constant":false,"inputs":[],"name":"drain","outputs":[],"payable":false,"type":"function"}`
@@ -163,7 +163,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_bool().ok_or("Invalid type returned")); r })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_bool().ok_or("Invalid type returned")?; r })) 
 	}
 
 	/// Auto-generated from: `{"constant":true,"inputs":[{"name":"_name","type":"bytes32"},{"name":"_key","type":"string"}],"name":"getUint","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"}`
@@ -175,7 +175,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_uint().ok_or("Invalid type returned")); util::U256::from(r.as_ref()) })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_uint().ok_or("Invalid type returned")?; util::U256::from(r.as_ref()) })) 
 	}
 
 	/// Auto-generated from: `{"constant":true,"inputs":[{"name":"_name","type":"bytes32"},{"name":"_key","type":"string"}],"name":"get","outputs":[{"name":"","type":"bytes32"}],"payable":false,"type":"function"}`
@@ -187,7 +187,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_fixed_bytes().ok_or("Invalid type returned")); util::H256::from_slice(r.as_ref()) })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_fixed_bytes().ok_or("Invalid type returned")?; util::H256::from_slice(r.as_ref()) })) 
 	}
 
 	/// Auto-generated from: `{"constant":true,"inputs":[],"name":"fee","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"}`
@@ -199,7 +199,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_uint().ok_or("Invalid type returned")); util::U256::from(r.as_ref()) })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_uint().ok_or("Invalid type returned")?; util::U256::from(r.as_ref()) })) 
 	}
 
 	/// Auto-generated from: `{"constant":true,"inputs":[{"name":"_name","type":"bytes32"}],"name":"getOwner","outputs":[{"name":"","type":"address"}],"payable":false,"type":"function"}`
@@ -211,7 +211,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_address().ok_or("Invalid type returned")); util::Address::from(r) })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_address().ok_or("Invalid type returned")?; util::Address::from(r) })) 
 	}
 
 	/// Auto-generated from: `{"constant":true,"inputs":[{"name":"","type":"address"}],"name":"reverse","outputs":[{"name":"","type":"string"}],"payable":false,"type":"function"}`
@@ -223,7 +223,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_string().ok_or("Invalid type returned")); r })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_string().ok_or("Invalid type returned")?; r })) 
 	}
 
 	/// Auto-generated from: `{"constant":false,"inputs":[{"name":"_name","type":"bytes32"},{"name":"_key","type":"string"},{"name":"_value","type":"uint256"}],"name":"setUint","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"}`
@@ -235,7 +235,7 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_bool().ok_or("Invalid type returned")); r })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_bool().ok_or("Invalid type returned")?; r })) 
 	}
 
 	/// Auto-generated from: `{"constant":false,"inputs":[],"name":"removeReverse","outputs":[],"payable":false,"type":"function"}`
@@ -259,6 +259,6 @@ impl Registry {
 		).map_err(Self::as_string)?;
 		let output = call.decode_output((self.do_call)(self.address.clone(), data)?).map_err(Self::as_string)?;
 		let mut result = output.into_iter().rev().collect::<Vec<_>>();
-		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = try!(r.to_bool().ok_or("Invalid type returned")); r })) 
+		Ok(({ let r = result.pop().ok_or("Invalid return arity")?; let r = r.to_bool().ok_or("Invalid type returned")?; r })) 
 	}
 }

ethcore/src/engines/authority_round.rs

@@ -107,7 +107,7 @@ impl AuthorityRound {
 				params: params,
 				our_params: our_params,
 				builtins: builtins,
-				transition_service: try!(IoService::<()>::start()),
+				transition_service: IoService::<()>::start()?,
 				message_channel: Mutex::new(None),
 				step: AtomicUsize::new(initial_step),
 				proposed: AtomicBool::new(false),
@@ -117,7 +117,7 @@ impl AuthorityRound {
 		// Do not initialize timeouts for tests.
 		if should_timeout {
 			let handler = TransitionHandler { engine: Arc::downgrade(&engine) };
-			try!(engine.transition_service.register_handler(Arc::new(handler)));
+			engine.transition_service.register_handler(Arc::new(handler))?;
 		}
 		Ok(engine)
 	}
@@ -263,20 +263,20 @@ impl Engine for AuthorityRound {
 
 	/// Check if the signature belongs to the correct proposer.
 	fn verify_block_unordered(&self, header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
-		let header_step = try!(header_step(header));
+		let header_step = header_step(header)?;
 		// Give one step slack if step is lagging, double vote is still not possible.
 		if header_step <= self.step.load(AtomicOrdering::SeqCst) + 1 {
-			let proposer_signature = try!(header_signature(header));
-			let ok_sig = try!(verify_address(self.step_proposer(header_step), &proposer_signature, &header.bare_hash()));
+			let proposer_signature = header_signature(header)?;
+			let ok_sig = verify_address(self.step_proposer(header_step), &proposer_signature, &header.bare_hash())?;
 			if ok_sig {
 				Ok(())
 			} else {
 				trace!(target: "poa", "verify_block_unordered: invalid seal signature");
-				try!(Err(BlockError::InvalidSeal))
+				Err(BlockError::InvalidSeal)?
 			}
 		} else {
 			trace!(target: "poa", "verify_block_unordered: block from the future");
-			try!(Err(BlockError::InvalidSeal))
+			Err(BlockError::InvalidSeal)?
 		}
 	}
 
@@ -285,11 +285,11 @@ impl Engine for AuthorityRound {
 			return Err(From::from(BlockError::RidiculousNumber(OutOfBounds { min: Some(1), max: None, found: header.number() })));
 		}
 
-		let step = try!(header_step(header));
+		let step = header_step(header)?;
 		// Check if parent is from a previous step.
-		if step == try!(header_step(parent)) {
+		if step == header_step(parent)? {
 			trace!(target: "poa", "Multiple blocks proposed for step {}.", step);
-			try!(Err(EngineError::DoubleVote(header.author().clone())));
+			Err(EngineError::DoubleVote(header.author().clone()))?;
 		}
 
 		let gas_limit_divisor = self.our_params.gas_limit_bound_divisor;
@@ -302,7 +302,7 @@ impl Engine for AuthorityRound {
 	}
 
 	fn verify_transaction_basic(&self, t: &SignedTransaction, _header: &Header) -> Result<(), Error> {
-		try!(t.check_low_s());
+		t.check_low_s()?;
 		Ok(())
 	}
 

ethcore/src/engines/basic_authority.rs

@@ -143,10 +143,10 @@ impl Engine for BasicAuthority {
 		use rlp::{UntrustedRlp, View};
 
 		// check the signature is legit.
-		let sig = try!(UntrustedRlp::new(&header.seal()[0]).as_val::<H520>());
-		let signer = public_to_address(&try!(recover(&sig.into(), &header.bare_hash())));
+		let sig = UntrustedRlp::new(&header.seal()[0]).as_val::<H520>()?;
+		let signer = public_to_address(&recover(&sig.into(), &header.bare_hash())?);
 		if !self.our_params.authorities.contains(&signer) {
-			return try!(Err(BlockError::InvalidSeal));
+			return Err(BlockError::InvalidSeal)?;
 		}
 		Ok(())
 	}
@@ -171,7 +171,7 @@ impl Engine for BasicAuthority {
 	}
 
 	fn verify_transaction_basic(&self, t: &SignedTransaction, _header: &Header) -> result::Result<(), Error> {
-		try!(t.check_low_s());
+		t.check_low_s()?;
 		Ok(())
 	}
 

ethcore/src/engines/tendermint/message.rs

@@ -51,9 +51,9 @@ impl ConsensusMessage {
 
 	pub fn new_proposal(header: &Header) -> Result<Self, ::rlp::DecoderError> {
 		Ok(ConsensusMessage {
-			signature: try!(UntrustedRlp::new(header.seal().get(1).expect("seal passed basic verification; seal has 3 fields; qed").as_slice()).as_val()),
+			signature: UntrustedRlp::new(header.seal().get(1).expect("seal passed basic verification; seal has 3 fields; qed").as_slice()).as_val()?,
 			height: header.number() as Height,
-			round: try!(consensus_round(header)),
+			round: consensus_round(header)?,
 			step: Step::Propose,
 			block_hash: Some(header.bare_hash()),
 		})
@@ -92,7 +92,7 @@ impl ConsensusMessage {
 	pub fn verify(&self) -> Result<Address, Error> {
 		let full_rlp = ::rlp::encode(self);
 		let block_info = Rlp::new(&full_rlp).at(1);
-		let public_key = try!(recover(&self.signature.into(), &block_info.as_raw().sha3()));
+		let public_key = recover(&self.signature.into(), &block_info.as_raw().sha3())?;
 		Ok(public_to_address(&public_key))
 	}
 
@@ -134,7 +134,7 @@ impl Ord for ConsensusMessage {
 
 impl Decodable for Step {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
-		match try!(decoder.as_rlp().as_val()) {
+		match decoder.as_rlp().as_val()? {
 			0u8 => Ok(Step::Propose),
 			1 => Ok(Step::Prevote),
 			2 => Ok(Step::Precommit),
@@ -153,13 +153,13 @@ impl Encodable for Step {
 impl Decodable for ConsensusMessage {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let rlp = decoder.as_rlp();
-		let m = try!(rlp.at(1));
-		let block_message: H256 = try!(m.val_at(3));
+		let m = rlp.at(1)?;
+		let block_message: H256 = m.val_at(3)?;
 		Ok(ConsensusMessage {
-			signature: try!(rlp.val_at(0)),
-			height: try!(m.val_at(0)),
-			round: try!(m.val_at(1)),
-			step: try!(m.val_at(2)),
+			signature: rlp.val_at(0)?,
+			height: m.val_at(0)?,
+			round: m.val_at(1)?,
+			step: m.val_at(2)?,
 			block_hash: match block_message.is_zero() {
 				true => None,
 				false => Some(block_message),

ethcore/src/engines/tendermint/mod.rs

@@ -109,7 +109,7 @@ impl Tendermint {
 				params: params,
 				our_params: our_params,
 				builtins: builtins,
-				step_service: try!(IoService::<Step>::start()),
+				step_service: IoService::<Step>::start()?,
 				authority: RwLock::new(Address::default()),
 				password: RwLock::new(None),
 				height: AtomicUsize::new(1),
@@ -123,7 +123,7 @@ impl Tendermint {
 				proposal: RwLock::new(None),
 			});
 		let handler = TransitionHandler { engine: Arc::downgrade(&engine) };
-		try!(engine.step_service.register_handler(Arc::new(handler)));
+		engine.step_service.register_handler(Arc::new(handler))?;
 		Ok(engine)
 	}
 
@@ -455,11 +455,11 @@ impl Engine for Tendermint {
 
 	fn handle_message(&self, rlp: &[u8]) -> Result<(), Error> {
 		let rlp = UntrustedRlp::new(rlp);
-		let message: ConsensusMessage = try!(rlp.as_val());
+		let message: ConsensusMessage = rlp.as_val()?;
 		if !self.votes.is_old_or_known(&message) {
-			let sender = public_to_address(&try!(recover(&message.signature.into(), &try!(rlp.at(1)).as_raw().sha3())));
+			let sender = public_to_address(&recover(&message.signature.into(), &rlp.at(1)?.as_raw().sha3())?);
 			if !self.is_authority(&sender) {
-				try!(Err(EngineError::NotAuthorized(sender)));
+				Err(EngineError::NotAuthorized(sender))?;
 			}
 			self.broadcast_message(rlp.as_raw().to_vec());
 			trace!(target: "poa", "Handling a valid {:?} from {}.", message, sender);
@@ -491,10 +491,10 @@ impl Engine for Tendermint {
 	}
 
 	fn verify_block_unordered(&self, header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
-		let proposal = try!(ConsensusMessage::new_proposal(header));	
-		let proposer = try!(proposal.verify());
+		let proposal = ConsensusMessage::new_proposal(header)?;	
+		let proposer = proposal.verify()?;
 		if !self.is_authority(&proposer) {
-			try!(Err(EngineError::NotAuthorized(proposer)))
+			Err(EngineError::NotAuthorized(proposer))?
 		}
 
 		let precommit_hash = proposal.precommit_hash();
@@ -502,20 +502,20 @@ impl Engine for Tendermint {
 		let mut signature_count = 0;
 		let mut origins = HashSet::new();
 		for rlp in UntrustedRlp::new(signatures_field).iter() {
-			let precommit: ConsensusMessage = ConsensusMessage::new_commit(&proposal, try!(rlp.as_val()));
+			let precommit: ConsensusMessage = ConsensusMessage::new_commit(&proposal, rlp.as_val()?);
 			let address = match self.votes.get(&precommit) {
 				Some(a) => a,
-				None => public_to_address(&try!(recover(&precommit.signature.into(), &precommit_hash))),
+				None => public_to_address(&recover(&precommit.signature.into(), &precommit_hash)?),
 			};
 			if !self.our_params.authorities.contains(&address) {
-				try!(Err(EngineError::NotAuthorized(address.to_owned())))
+				Err(EngineError::NotAuthorized(address.to_owned()))?
 			}
 
 			if origins.insert(address) {
 				signature_count += 1;
 			} else {
 				warn!(target: "poa", "verify_block_unordered: Duplicate signature from {} on the seal.", address);
-				try!(Err(BlockError::InvalidSeal));
+				Err(BlockError::InvalidSeal)?;
 			}
 		}
 
@@ -524,34 +524,34 @@ impl Engine for Tendermint {
 			let signatures_len = signatures_field.len();
 			// Proposal has to have an empty signature list.
 			if signatures_len != 1 {
-				try!(Err(EngineError::BadSealFieldSize(OutOfBounds {
+				Err(EngineError::BadSealFieldSize(OutOfBounds {
 					min: Some(1),
 					max: Some(1),
 					found: signatures_len
-				})));
+				}))?;
 			}
-			try!(self.is_round_proposer(proposal.height, proposal.round, &proposer));
+			self.is_round_proposer(proposal.height, proposal.round, &proposer)?;
 		}
 		Ok(())
 	}
 
 	fn verify_block_family(&self, header: &Header, parent: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
 		if header.number() == 0 {
-			try!(Err(BlockError::RidiculousNumber(OutOfBounds { min: Some(1), max: None, found: header.number() })));
+			Err(BlockError::RidiculousNumber(OutOfBounds { min: Some(1), max: None, found: header.number() }))?;
 		}
 
 		let gas_limit_divisor = self.our_params.gas_limit_bound_divisor;
 		let min_gas = parent.gas_limit().clone() - parent.gas_limit().clone() / gas_limit_divisor;
 		let max_gas = parent.gas_limit().clone() + parent.gas_limit().clone() / gas_limit_divisor;
 		if header.gas_limit() <= &min_gas || header.gas_limit() >= &max_gas {
-			try!(Err(BlockError::InvalidGasLimit(OutOfBounds { min: Some(min_gas), max: Some(max_gas), found: header.gas_limit().clone() })));
+			Err(BlockError::InvalidGasLimit(OutOfBounds { min: Some(min_gas), max: Some(max_gas), found: header.gas_limit().clone() }))?;
 		}
 
 		Ok(())
 	}
 
 	fn verify_transaction_basic(&self, t: &SignedTransaction, _header: &Header) -> Result<(), Error> {
-		try!(t.check_low_s());
+		t.check_low_s()?;
 		Ok(())
 	}
 

ethcore/src/ethereum/ethash.rs

@@ -240,8 +240,8 @@ impl Engine for Ethash {
 				Mismatch { expected: self.seal_fields(), found: header.seal().len() }
 			)));
 		}
-		try!(UntrustedRlp::new(&header.seal()[0]).as_val::<H256>());
-		try!(UntrustedRlp::new(&header.seal()[1]).as_val::<H64>());
+		UntrustedRlp::new(&header.seal()[0]).as_val::<H256>()?;
+		UntrustedRlp::new(&header.seal()[1]).as_val::<H64>()?;
 
 		// TODO: consider removing these lines.
 		let min_difficulty = self.ethash_params.minimum_difficulty;
@@ -312,7 +312,7 @@ impl Engine for Ethash {
 
 	fn verify_transaction_basic(&self, t: &SignedTransaction, header: &Header) -> result::Result<(), Error> {
 		if header.number() >= self.ethash_params.homestead_transition {
-			try!(t.check_low_s());
+			t.check_low_s()?;
 		}
 
 		if let Some(n) = t.network_id() {

ethcore/src/evm/interpreter/gasometer.rs

@@ -159,39 +159,39 @@ impl<Gas: CostType> Gasometer<Gas> {
 				Request::Gas(gas)
 			},
 			instructions::MSTORE | instructions::MLOAD => {
-				Request::GasMem(default_gas, try!(mem_needed_const(stack.peek(0), 32)))
+				Request::GasMem(default_gas, mem_needed_const(stack.peek(0), 32)?)
 			},
 			instructions::MSTORE8 => {
-				Request::GasMem(default_gas, try!(mem_needed_const(stack.peek(0), 1)))
+				Request::GasMem(default_gas, mem_needed_const(stack.peek(0), 1)?)
 			},
 			instructions::RETURN => {
-				Request::GasMem(default_gas, try!(mem_needed(stack.peek(0), stack.peek(1))))
+				Request::GasMem(default_gas, mem_needed(stack.peek(0), stack.peek(1))?)
 			},
 			instructions::SHA3 => {
-				let w = overflowing!(add_gas_usize(try!(Gas::from_u256(*stack.peek(1))), 31));
+				let w = overflowing!(add_gas_usize(Gas::from_u256(*stack.peek(1))?, 31));
 				let words = w >> 5;
 				let gas = Gas::from(schedule.sha3_gas) + (Gas::from(schedule.sha3_word_gas) * words);
-				Request::GasMem(gas, try!(mem_needed(stack.peek(0), stack.peek(1))))
+				Request::GasMem(gas, mem_needed(stack.peek(0), stack.peek(1))?)
 			},
 			instructions::CALLDATACOPY | instructions::CODECOPY => {
-				Request::GasMemCopy(default_gas, try!(mem_needed(stack.peek(0), stack.peek(2))), try!(Gas::from_u256(*stack.peek(2))))
+				Request::GasMemCopy(default_gas, mem_needed(stack.peek(0), stack.peek(2))?, Gas::from_u256(*stack.peek(2))?)
 			},
 			instructions::EXTCODECOPY => {
-				Request::GasMemCopy(schedule.extcodecopy_base_gas.into(), try!(mem_needed(stack.peek(1), stack.peek(3))), try!(Gas::from_u256(*stack.peek(3))))
+				Request::GasMemCopy(schedule.extcodecopy_base_gas.into(), mem_needed(stack.peek(1), stack.peek(3))?, Gas::from_u256(*stack.peek(3))?)
 			},
 			instructions::LOG0...instructions::LOG4 => {
 				let no_of_topics = instructions::get_log_topics(instruction);
 				let log_gas = schedule.log_gas + schedule.log_topic_gas * no_of_topics;
 
-				let data_gas = overflowing!(try!(Gas::from_u256(*stack.peek(1))).overflow_mul(Gas::from(schedule.log_data_gas)));
+				let data_gas = overflowing!(Gas::from_u256(*stack.peek(1))?.overflow_mul(Gas::from(schedule.log_data_gas)));
 				let gas = overflowing!(data_gas.overflow_add(Gas::from(log_gas)));
-				Request::GasMem(gas, try!(mem_needed(stack.peek(0), stack.peek(1))))
+				Request::GasMem(gas, mem_needed(stack.peek(0), stack.peek(1))?)
 			},
 			instructions::CALL | instructions::CALLCODE => {
 				let mut gas = Gas::from(schedule.call_gas);
 				let mem = cmp::max(
-					try!(mem_needed(stack.peek(5), stack.peek(6))),
-					try!(mem_needed(stack.peek(3), stack.peek(4)))
+					mem_needed(stack.peek(5), stack.peek(6))?,
+					mem_needed(stack.peek(3), stack.peek(4))?
 				);
 
 				let address = u256_to_address(stack.peek(1));
@@ -216,8 +216,8 @@ impl<Gas: CostType> Gasometer<Gas> {
 			instructions::DELEGATECALL => {
 				let gas = Gas::from(schedule.call_gas);
 				let mem = cmp::max(
-					try!(mem_needed(stack.peek(4), stack.peek(5))),
-					try!(mem_needed(stack.peek(2), stack.peek(3)))
+					mem_needed(stack.peek(4), stack.peek(5))?,
+					mem_needed(stack.peek(2), stack.peek(3))?
 				);
 				let requested = *stack.peek(0);
 
@@ -225,7 +225,7 @@ impl<Gas: CostType> Gasometer<Gas> {
 			},
 			instructions::CREATE => {
 				let gas = Gas::from(schedule.create_gas);
-				let mem = try!(mem_needed(stack.peek(1), stack.peek(2)));
+				let mem = mem_needed(stack.peek(1), stack.peek(2))?;
 
 				Request::GasMemProvide(gas, mem, None)
 			},
@@ -248,7 +248,7 @@ impl<Gas: CostType> Gasometer<Gas> {
 				}
 			},
 			Request::GasMem(gas, mem_size) => {
-				let (mem_gas_cost, new_mem_gas, new_mem_size) = try!(self.mem_gas_cost(schedule, current_mem_size, &mem_size));
+				let (mem_gas_cost, new_mem_gas, new_mem_size) = self.mem_gas_cost(schedule, current_mem_size, &mem_size)?;
 				let gas = overflowing!(gas.overflow_add(mem_gas_cost));
 				InstructionRequirements {
 					gas_cost: gas,
@@ -258,9 +258,9 @@ impl<Gas: CostType> Gasometer<Gas> {
 				}
 			},
 			Request::GasMemProvide(gas, mem_size, requested) => {
-				let (mem_gas_cost, new_mem_gas, new_mem_size) = try!(self.mem_gas_cost(schedule, current_mem_size, &mem_size));
+				let (mem_gas_cost, new_mem_gas, new_mem_size) = self.mem_gas_cost(schedule, current_mem_size, &mem_size)?;
 				let gas = overflowing!(gas.overflow_add(mem_gas_cost));
-				let provided = try!(self.gas_provided(schedule, gas, requested));
+				let provided = self.gas_provided(schedule, gas, requested)?;
 				let total_gas = overflowing!(gas.overflow_add(provided));
 
 				InstructionRequirements {
@@ -271,7 +271,7 @@ impl<Gas: CostType> Gasometer<Gas> {
 				}
 			},
 			Request::GasMemCopy(gas, mem_size, copy) => {
-				let (mem_gas_cost, new_mem_gas, new_mem_size) = try!(self.mem_gas_cost(schedule, current_mem_size, &mem_size));
+				let (mem_gas_cost, new_mem_gas, new_mem_size) = self.mem_gas_cost(schedule, current_mem_size, &mem_size)?;
 				let copy = overflowing!(add_gas_usize(copy, 31)) >> 5;
 				let copy_gas = Gas::from(schedule.copy_gas) * copy;
 				let gas = overflowing!(gas.overflow_add(copy_gas));
@@ -303,7 +303,7 @@ impl<Gas: CostType> Gasometer<Gas> {
 		let req_mem_size_rounded = (overflowing!(mem_size.overflow_add(Gas::from(31 as usize))) >> 5) << 5;
 
 		let (mem_gas_cost, new_mem_gas) = if req_mem_size_rounded > current_mem_size {
-			let new_mem_gas = try!(gas_for_mem(req_mem_size_rounded));
+			let new_mem_gas = gas_for_mem(req_mem_size_rounded)?;
 			(new_mem_gas - self.current_mem_gas, new_mem_gas)
 		} else {
 			(Gas::from(0), self.current_mem_gas)

ethcore/src/evm/interpreter/mod.rs

@@ -107,7 +107,7 @@ impl<Cost: CostType> evm::Evm for Interpreter<Cost> {
 		let code = &params.code.as_ref().expect("exec always called with code; qed");
 		let valid_jump_destinations = self.cache.jump_destinations(&params.code_hash, code);
 
-		let mut gasometer = Gasometer::<Cost>::new(try!(Cost::from_u256(params.gas)));
+		let mut gasometer = Gasometer::<Cost>::new(Cost::from_u256(params.gas)?);
 		let mut stack = VecStack::with_capacity(ext.schedule().stack_limit, U256::zero());
 		let mut reader = CodeReader::new(code);
 		let infos = &*instructions::INSTRUCTIONS;
@@ -117,14 +117,14 @@ impl<Cost: CostType> evm::Evm for Interpreter<Cost> {
 			reader.position += 1;
 
 			let info = &infos[instruction as usize];
-			try!(self.verify_instruction(ext, instruction, info, &stack));
+			self.verify_instruction(ext, instruction, info, &stack)?;
 
 			// Calculate gas cost
-			let requirements = try!(gasometer.requirements(ext, instruction, info, &stack, self.mem.size()));
+			let requirements = gasometer.requirements(ext, instruction, info, &stack, self.mem.size())?;
 			// TODO: make compile-time removable if too much of a performance hit.
 			let trace_executed = ext.trace_prepare_execute(reader.position - 1, instruction, &requirements.gas_cost.as_u256());
 
-			try!(gasometer.verify_gas(&requirements.gas_cost));
+			gasometer.verify_gas(&requirements.gas_cost)?;
 			self.mem.expand(requirements.memory_required_size);
 			gasometer.current_mem_gas = requirements.memory_total_gas;
 			gasometer.current_gas = gasometer.current_gas - requirements.gas_cost;
@@ -137,9 +137,9 @@ impl<Cost: CostType> evm::Evm for Interpreter<Cost> {
 			};
 
 			// Execute instruction
-			let result = try!(self.exec_instruction(
+			let result = self.exec_instruction(
 				gasometer.current_gas, &params, ext, instruction, &mut reader, &mut stack, requirements.provide_gas
-			));
+			)?;
 
 			evm_debug!({ informant.after_instruction(instruction) });
 
@@ -154,7 +154,7 @@ impl<Cost: CostType> evm::Evm for Interpreter<Cost> {
 			// Advance
 			match result {
 				InstructionResult::JumpToPosition(position) => {
-					let pos = try!(self.verify_jump(position, &valid_jump_destinations));
+					let pos = self.verify_jump(position, &valid_jump_destinations)?;
 					reader.position = pos;
 				},
 				InstructionResult::StopExecutionNeedsReturn(gas, off, size) => {
@@ -513,7 +513,7 @@ impl<Cost: CostType> Interpreter<Cost> {
 				stack.push(ext.env_info().gas_limit.clone());
 			},
 			_ => {
-				try!(self.exec_stack_instruction(instruction, stack));
+				self.exec_stack_instruction(instruction, stack)?;
 			}
 		};
 		Ok(InstructionResult::Ok)

ethcore/src/executive.rs

@@ -122,10 +122,10 @@ impl<'a> Executive<'a> {
 		mut tracer: T,
 		mut vm_tracer: V
 	) -> Result<Executed, ExecutionError> where T: Tracer, V: VMTracer {
-		let sender = try!(t.sender().map_err(|e| {
+		let sender = t.sender().map_err(|e| {
 			let message = format!("Transaction malformed: {:?}", e);
 			ExecutionError::TransactionMalformed(message)
-		}));
+		})?;
 		let nonce = self.state.nonce(&sender);
 
 		let schedule = self.engine.schedule(self.info);
@@ -206,7 +206,7 @@ impl<'a> Executive<'a> {
 		};
 
 		// finalize here!
-		Ok(try!(self.finalize(t, substate, gas_left, output, tracer.traces(), vm_tracer.drain())))
+		Ok(self.finalize(t, substate, gas_left, output, tracer.traces(), vm_tracer.drain())?)
 	}
 
 	fn exec_vm<T, V>(

ethcore/src/header.rs

@@ -265,26 +265,26 @@ impl Decodable for Header {
 		let r = decoder.as_rlp();
 
 		let mut blockheader = Header {
-			parent_hash: try!(r.val_at(0)),
-			uncles_hash: try!(r.val_at(1)),
-			author: try!(r.val_at(2)),
-			state_root: try!(r.val_at(3)),
-			transactions_root: try!(r.val_at(4)),
-			receipts_root: try!(r.val_at(5)),
-			log_bloom: try!(r.val_at(6)),
-			difficulty: try!(r.val_at(7)),
-			number: try!(r.val_at(8)),
-			gas_limit: try!(r.val_at(9)),
-			gas_used: try!(r.val_at(10)),
-			timestamp: try!(r.val_at(11)),
-			extra_data: try!(r.val_at(12)),
+			parent_hash: r.val_at(0)?,
+			uncles_hash: r.val_at(1)?,
+			author: r.val_at(2)?,
+			state_root: r.val_at(3)?,
+			transactions_root: r.val_at(4)?,
+			receipts_root: r.val_at(5)?,
+			log_bloom: r.val_at(6)?,
+			difficulty: r.val_at(7)?,
+			number: r.val_at(8)?,
+			gas_limit: r.val_at(9)?,
+			gas_used: r.val_at(10)?,
+			timestamp: r.val_at(11)?,
+			extra_data: r.val_at(12)?,
 			seal: vec![],
 			hash: RefCell::new(Some(r.as_raw().sha3())),
 			bare_hash: RefCell::new(None),
 		};
 
 		for i in 13..r.item_count() {
-			blockheader.seal.push(try!(r.at(i)).as_raw().to_vec())
+			blockheader.seal.push(r.at(i)?.as_raw().to_vec())
 		}
 
 		Ok(blockheader)

ethcore/src/migrations/state/v7.rs

@@ -109,7 +109,7 @@ impl OverlayRecentV7 {
 	// walk all journal entries in the database backwards.
 	// find migrations for any possible inserted keys.
 	fn walk_journal(&mut self, source: Arc<Database>) -> Result<(), Error> {
-		if let Some(val) = try!(source.get(None, V7_LATEST_ERA_KEY).map_err(Error::Custom)) {
+		if let Some(val) = source.get(None, V7_LATEST_ERA_KEY).map_err(Error::Custom)? {
 			let mut era = decode::<u64>(&val);
 			loop {
 				let mut index: usize = 0;
@@ -120,7 +120,7 @@ impl OverlayRecentV7 {
 						r.out()
 					};
 
-					if let Some(journal_raw) = try!(source.get(None, &entry_key).map_err(Error::Custom)) {
+					if let Some(journal_raw) = source.get(None, &entry_key).map_err(Error::Custom)? {
 						let rlp = Rlp::new(&journal_raw);
 
 						// migrate all inserted keys.
@@ -153,8 +153,8 @@ impl OverlayRecentV7 {
 	// replace all possible inserted/deleted keys with their migrated counterparts
 	// and commit the altered entries.
 	fn migrate_journal(&self, source: Arc<Database>, mut batch: Batch, dest: &mut Database) -> Result<(), Error> {
-		if let Some(val) = try!(source.get(None, V7_LATEST_ERA_KEY).map_err(Error::Custom)) {
-			try!(batch.insert(V7_LATEST_ERA_KEY.into(), val.clone().to_vec(), dest));
+		if let Some(val) = source.get(None, V7_LATEST_ERA_KEY).map_err(Error::Custom)? {
+			batch.insert(V7_LATEST_ERA_KEY.into(), val.clone().to_vec(), dest)?;
 
 			let mut era = decode::<u64>(&val);
 			loop {
@@ -166,7 +166,7 @@ impl OverlayRecentV7 {
 						r.out()
 					};
 
-					if let Some(journal_raw) = try!(source.get(None, &entry_key).map_err(Error::Custom)) {
+					if let Some(journal_raw) = source.get(None, &entry_key).map_err(Error::Custom)? {
 						let rlp = Rlp::new(&journal_raw);
 						let id: H256 = rlp.val_at(0);
 						let mut inserted_keys: Vec<(H256, Bytes)> = Vec::new();
@@ -202,7 +202,7 @@ impl OverlayRecentV7 {
 						stream.append(&deleted_keys);
 
 						// and insert it into the new database.
-						try!(batch.insert(entry_key, stream.out(), dest));
+						batch.insert(entry_key, stream.out(), dest)?;
 
 						index += 1;
 					} else {
@@ -233,7 +233,7 @@ impl Migration for OverlayRecentV7 {
 		let mut batch = Batch::new(config, col);
 
 		// check version metadata.
-		match try!(source.get(None, V7_VERSION_KEY).map_err(Error::Custom)) {
+		match source.get(None, V7_VERSION_KEY).map_err(Error::Custom)? {
 			Some(ref version) if decode::<u32>(&*version) == DB_VERSION => {}
 			_ => return Err(Error::MigrationImpossible), // missing or wrong version
 		}
@@ -255,10 +255,10 @@ impl Migration for OverlayRecentV7 {
 				}
 			}
 
-			try!(batch.insert(key, value.into_vec(), dest));
+			batch.insert(key, value.into_vec(), dest)?;
 		}
 
-		try!(self.walk_journal(source.clone()));
+		self.walk_journal(source.clone())?;
 		self.migrate_journal(source, batch, dest)
 	}
 }

ethcore/src/migrations/v10.rs

@@ -32,7 +32,7 @@ use util::{Database, DBTransaction};
 /// Can be called on upgraded database with no issues (will do nothing).
 pub fn generate_bloom(source: Arc<Database>, dest: &mut Database) -> Result<(), Error> {
 	trace!(target: "migration", "Account bloom upgrade started");
-	let best_block_hash = match try!(source.get(COL_EXTRA, b"best")) {
+	let best_block_hash = match source.get(COL_EXTRA, b"best")? {
 		// no migration needed
 		None => {
 			trace!(target: "migration", "No best block hash, skipping");
@@ -40,7 +40,7 @@ pub fn generate_bloom(source: Arc<Database>, dest: &mut Database) -> Result<(),
 		},
 		Some(hash) => hash,
 	};
-	let best_block_header = match try!(source.get(COL_HEADERS, &best_block_hash)) {
+	let best_block_header = match source.get(COL_HEADERS, &best_block_hash)? {
 		// no best block, nothing to do
 		None => {
 			trace!(target: "migration", "No best block header, skipping");
@@ -58,9 +58,9 @@ pub fn generate_bloom(source: Arc<Database>, dest: &mut Database) -> Result<(),
 			source.clone(),
 			journaldb::Algorithm::OverlayRecent,
 			COL_STATE);
-		let account_trie = try!(TrieDB::new(state_db.as_hashdb(), &state_root).map_err(|e| Error::Custom(format!("Cannot open trie: {:?}", e))));
-		for item in try!(account_trie.iter().map_err(|_| Error::MigrationImpossible)) {
-			let (ref account_key, _) = try!(item.map_err(|_| Error::MigrationImpossible));
+		let account_trie = TrieDB::new(state_db.as_hashdb(), &state_root).map_err(|e| Error::Custom(format!("Cannot open trie: {:?}", e)))?;
+		for item in account_trie.iter().map_err(|_| Error::MigrationImpossible)? {
+			let (ref account_key, _) = item.map_err(|_| Error::MigrationImpossible)?;
 			let account_key_hash = H256::from_slice(account_key);
 			bloom.set(&*account_key_hash);
 		}
@@ -71,8 +71,8 @@ pub fn generate_bloom(source: Arc<Database>, dest: &mut Database) -> Result<(),
 	trace!(target: "migration", "Generated {} bloom updates", bloom_journal.entries.len());
 
 	let mut batch = DBTransaction::new(dest);
-	try!(StateDB::commit_bloom(&mut batch, bloom_journal).map_err(|_| Error::Custom("Failed to commit bloom".to_owned())));
-	try!(dest.write(batch));
+	StateDB::commit_bloom(&mut batch, bloom_journal).map_err(|_| Error::Custom("Failed to commit bloom".to_owned()))?;
+	dest.write(batch)?;
 
 	trace!(target: "migration", "Finished bloom update");
 
@@ -104,12 +104,12 @@ impl Migration for ToV10 {
 		let mut batch = Batch::new(config, col);
 		for (key, value) in source.iter(col) {
 			self.progress.tick();
-			try!(batch.insert(key.to_vec(), value.to_vec(), dest));
+			batch.insert(key.to_vec(), value.to_vec(), dest)?;
 		}
-		try!(batch.commit(dest));
+		batch.commit(dest)?;
 
 		if col == COL_STATE {
-			try!(generate_bloom(source, dest));
+			generate_bloom(source, dest)?;
 		}
 
 		Ok(())

ethcore/src/migrations/v9.rs

@@ -63,17 +63,17 @@ impl Migration for ToV9 {
 			self.progress.tick();
 			match self.extract {
 				Extract::Header => {
-					try!(batch.insert(key.to_vec(), Rlp::new(&value).at(0).as_raw().to_vec(), dest))
+					batch.insert(key.to_vec(), Rlp::new(&value).at(0).as_raw().to_vec(), dest)?
 				},
 				Extract::Body => {
 					let mut body = RlpStream::new_list(2);
 					let block_rlp = Rlp::new(&value);
 					body.append_raw(block_rlp.at(1).as_raw(), 1);
 					body.append_raw(block_rlp.at(2).as_raw(), 1);
-					try!(batch.insert(key.to_vec(), body.out(), dest))
+					batch.insert(key.to_vec(), body.out(), dest)?
 				},
 				Extract::All => {
-					try!(batch.insert(key.to_vec(), value.to_vec(), dest))
+					batch.insert(key.to_vec(), value.to_vec(), dest)?
 				}
 			}
 		}

ethcore/src/miner/miner.rs

@@ -698,10 +698,10 @@ impl MinerService for Miner {
 				let mut state = block.state().clone();
 				let original_state = if analytics.state_diffing { Some(state.clone()) } else { None };
 
-				let sender = try!(t.sender().map_err(|e| {
+				let sender = t.sender().map_err(|e| {
 					let message = format!("Transaction malformed: {:?}", e);
 					ExecutionError::TransactionMalformed(message)
-				}));
+				})?;
 				let balance = state.balance(&sender);
 				let needed_balance = t.value + t.gas * t.gas_price;
 				if balance < needed_balance {
@@ -709,7 +709,7 @@ impl MinerService for Miner {
 					state.add_balance(&sender, &(needed_balance - balance), CleanupMode::NoEmpty);
 				}
 				let options = TransactOptions { tracing: analytics.transaction_tracing, vm_tracing: analytics.vm_tracing, check_nonce: false };
-				let mut ret = try!(Executive::new(&mut state, &env_info, &*self.engine, chain.vm_factory()).transact(t, options));
+				let mut ret = Executive::new(&mut state, &env_info, &*self.engine, chain.vm_factory()).transact(t, options)?;
 
 				// TODO gav move this into Executive.
 				ret.state_diff = original_state.map(|original| state.diff_from(original));
@@ -765,7 +765,7 @@ impl MinerService for Miner {
 	fn set_engine_signer(&self, address: Address, password: String) -> Result<(), AccountError> {
 		if self.seals_internally {
 			if let Some(ref ap) = self.accounts {
-				try!(ap.sign(address.clone(), Some(password.clone()), Default::default()));
+				ap.sign(address.clone(), Some(password.clone()), Default::default())?;
 			}
 			let mut sealing_work = self.sealing_work.lock();
 			sealing_work.enabled = self.engine.is_sealer(&address).unwrap_or(false);
@@ -1104,7 +1104,7 @@ impl MinerService for Miner {
 		result.and_then(|sealed| {
 			let n = sealed.header().number();
 			let h = sealed.header().hash();
-			try!(chain.import_sealed_block(sealed));
+			chain.import_sealed_block(sealed)?;
 			info!(target: "miner", "Submitted block imported OK. #{}: {}", Colour::White.bold().paint(format!("{}", n)), Colour::White.bold().paint(h.hex()));
 			Ok(())
 		})

ethcore/src/miner/price_info.rs

@@ -65,7 +65,7 @@ impl<F: Fn(PriceInfo) + Sync + Send + 'static> Handler<HttpStream> for SetPriceH
 impl PriceInfo {
 	pub fn get<F: Fn(PriceInfo) + Sync + Send + 'static>(set_price: F) -> Result<(), ()> {
 		// TODO: Handle each error type properly
-		let client = try!(Client::new().map_err(|_| ()));
+		let client = Client::new().map_err(|_| ())?;
 		thread::spawn(move || {
 			let (tx, rx) = mpsc::channel();
 			let url = FromStr::from_str("http://api.etherscan.io/api?module=stats&action=ethprice")

ethcore/src/miner/transaction_queue.rs

@@ -264,7 +264,7 @@ struct VerifiedTransaction {
 
 impl VerifiedTransaction {
 	fn new(transaction: SignedTransaction, origin: TransactionOrigin, min_block: Option<BlockNumber>) -> Result<Self, Error> {
-		try!(transaction.sender());
+		transaction.sender()?;
 		Ok(VerifiedTransaction {
 			transaction: transaction,
 			origin: origin,
@@ -732,9 +732,9 @@ impl TransactionQueue {
 		}
 
 		// Verify signature
-		try!(tx.check_low_s());
+		tx.check_low_s()?;
 
-		let vtx = try!(VerifiedTransaction::new(tx, origin, min_block));
+		let vtx = VerifiedTransaction::new(tx, origin, min_block)?;
 		let client_account = fetch_account(&vtx.sender());
 
 		let cost = vtx.transaction.value + vtx.transaction.gas_price * vtx.transaction.gas;
@@ -1138,13 +1138,13 @@ impl TransactionQueue {
 		if nonce > next_nonce {
 			// We have a gap - put to future.
 			// Insert transaction (or replace old one with lower gas price)
-			try!(check_too_cheap(
+			check_too_cheap(
 				Self::replace_transaction(tx, state_nonce, min_gas_price, &mut self.future, &mut self.by_hash, &mut self.local_transactions)
-			));
+			)?;
 			// Enforce limit in Future
 			let removed = self.future.enforce_limit(&mut self.by_hash, &mut self.local_transactions);
 			// Return an error if this transaction was not imported because of limit.
-			try!(check_if_removed(&address, &nonce, removed));
+			check_if_removed(&address, &nonce, removed)?;
 
 			debug!(target: "txqueue", "Importing transaction to future: {:?}", hash);
 			debug!(target: "txqueue", "status: {:?}", self.status());
@@ -1156,9 +1156,9 @@ impl TransactionQueue {
 		self.move_matching_future_to_current(address, nonce + U256::one(), state_nonce);
 
 		// Replace transaction if any
-		try!(check_too_cheap(
+		check_too_cheap(
 			Self::replace_transaction(tx, state_nonce, min_gas_price, &mut self.current, &mut self.by_hash, &mut self.local_transactions)
-		));
+		)?;
 		// Keep track of highest nonce stored in current
 		let new_max = self.last_nonces.get(&address).map_or(nonce, |n| cmp::max(nonce, *n));
 		self.last_nonces.insert(address, new_max);
@@ -1168,7 +1168,7 @@ impl TransactionQueue {
 		// If some transaction were removed because of limit we need to update last_nonces also.
 		self.update_last_nonces(&removed);
 		// Trigger error if the transaction we are importing was removed.
-		try!(check_if_removed(&address, &nonce, removed));
+		check_if_removed(&address, &nonce, removed)?;
 
 		debug!(target: "txqueue", "Imported transaction to current: {:?}", hash);
 		debug!(target: "txqueue", "status: {:?}", self.status());

ethcore/src/pod_state.rs

@@ -64,7 +64,7 @@ impl From<ethjson::spec::State> for PodState {
 impl fmt::Display for PodState {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		for (add, acc) in &self.0 {
-			try!(writeln!(f, "{} => {}", add, acc));
+			writeln!(f, "{} => {}", add, acc)?;
 		}
 		Ok(())
 	}

ethcore/src/service.rs

@@ -77,7 +77,7 @@ impl ClientService {
 		) -> Result<ClientService, Error>
 	{
 		let panic_handler = PanicHandler::new_in_arc();
-		let io_service = try!(IoService::<ClientIoMessage>::start());
+		let io_service = IoService::<ClientIoMessage>::start()?;
 		panic_handler.forward_from(&io_service);
 
 		info!("Configured for {} using {} engine", Colour::White.bold().paint(spec.name.clone()), Colour::Yellow.bold().paint(spec.engine.name()));
@@ -94,7 +94,7 @@ impl ClientService {
 		db_config.wal = config.db_wal;
 
 		let pruning = config.pruning;
-		let client = try!(Client::new(config, &spec, client_path, miner, io_service.channel(), &db_config));
+		let client = Client::new(config, &spec, client_path, miner, io_service.channel(), &db_config)?;
 
 		let snapshot_params = SnapServiceParams {
 			engine: spec.engine.clone(),
@@ -105,14 +105,14 @@ impl ClientService {
 			snapshot_root: snapshot_path.into(),
 			db_restore: client.clone(),
 		};
-		let snapshot = Arc::new(try!(SnapshotService::new(snapshot_params)));
+		let snapshot = Arc::new(SnapshotService::new(snapshot_params)?);
 
 		panic_handler.forward_from(&*client);
 		let client_io = Arc::new(ClientIoHandler {
 			client: client.clone(),
 			snapshot: snapshot.clone(),
 		});
-		try!(io_service.register_handler(client_io));
+		io_service.register_handler(client_io)?;
 
 		spec.engine.register_message_channel(io_service.channel());
 

ethcore/src/snapshot/account.rs

@@ -100,12 +100,12 @@ impl Account {
 			return Ok(::rlp::NULL_RLP.to_vec());
 		}
 
-		let db = try!(TrieDB::new(acct_db, &self.storage_root));
+		let db = TrieDB::new(acct_db, &self.storage_root)?;
 
 		let mut pairs = Vec::new();
 
-		for item in try!(db.iter()) {
-			let (k, v) = try!(item);
+		for item in db.iter()? {
+			let (k, v) = item?;
 			pairs.push((k, v));
 		}
 
@@ -158,24 +158,24 @@ impl Account {
 			return Ok((ACC_EMPTY, None));
 		}
 
-		let nonce = try!(rlp.val_at(0));
-		let balance = try!(rlp.val_at(1));
+		let nonce = rlp.val_at(0)?;
+		let balance = rlp.val_at(1)?;
 		let code_state: CodeState = {
-			let raw: u8 = try!(rlp.val_at(2));
-			try!(CodeState::from(raw))
+			let raw: u8 = rlp.val_at(2)?;
+			CodeState::from(raw)?
 		};
 
 		// load the code if it exists.
 		let (code_hash, new_code) = match code_state {
 			CodeState::Empty => (SHA3_EMPTY, None),
 			CodeState::Inline => {
-				let code: Bytes = try!(rlp.val_at(3));
+				let code: Bytes = rlp.val_at(3)?;
 				let code_hash = acct_db.insert(&code);
 
 				(code_hash, Some(code))
 			}
 			CodeState::Hash => {
-				let code_hash = try!(rlp.val_at(3));
+				let code_hash = rlp.val_at(3)?;
 
 				(code_hash, None)
 			}
@@ -185,12 +185,12 @@ impl Account {
 
 		{
 			let mut storage_trie = TrieDBMut::new(acct_db, &mut storage_root);
-			let pairs = try!(rlp.at(4));
+			let pairs = rlp.at(4)?;
 			for pair_rlp in pairs.iter() {
-				let k: Bytes  = try!(pair_rlp.val_at(0));
-				let v: Bytes = try!(pair_rlp.val_at(1));
+				let k: Bytes  = pair_rlp.val_at(0)?;
+				let v: Bytes = pair_rlp.val_at(1)?;
 
-				try!(storage_trie.insert(&k, &v));
+				storage_trie.insert(&k, &v)?;
 			}
 		}
 

ethcore/src/snapshot/block.rs

@@ -89,21 +89,21 @@ impl AbridgedBlock {
 
 		let mut header: Header = Default::default();
 		header.set_parent_hash(parent_hash);
-		header.set_author(try!(rlp.val_at(0)));
-		header.set_state_root(try!(rlp.val_at(1)));
-		header.set_log_bloom(try!(rlp.val_at(2)));
-		header.set_difficulty(try!(rlp.val_at(3)));
+		header.set_author(rlp.val_at(0)?);
+		header.set_state_root(rlp.val_at(1)?);
+		header.set_log_bloom(rlp.val_at(2)?);
+		header.set_difficulty(rlp.val_at(3)?);
 		header.set_number(number);
-		header.set_gas_limit(try!(rlp.val_at(4)));
-		header.set_gas_used(try!(rlp.val_at(5)));
-		header.set_timestamp(try!(rlp.val_at(6)));
-		header.set_extra_data(try!(rlp.val_at(7)));
+		header.set_gas_limit(rlp.val_at(4)?);
+		header.set_gas_used(rlp.val_at(5)?);
+		header.set_timestamp(rlp.val_at(6)?);
+		header.set_extra_data(rlp.val_at(7)?);
 
-		let transactions = try!(rlp.val_at(8));
-		let uncles: Vec<Header> = try!(rlp.val_at(9));
+		let transactions = rlp.val_at(8)?;
+		let uncles: Vec<Header> = rlp.val_at(9)?;
 
 		header.set_transactions_root(ordered_trie_root(
-			try!(rlp.at(8)).iter().map(|r| r.as_raw().to_owned())
+			rlp.at(8)?.iter().map(|r| r.as_raw().to_owned())
 		));
 		header.set_receipts_root(receipts_root);
 
@@ -113,7 +113,7 @@ impl AbridgedBlock {
 
 		let mut seal_fields = Vec::new();
 		for i in (HEADER_FIELDS + BLOCK_FIELDS)..rlp.item_count() {
-			let seal_rlp = try!(rlp.at(i));
+			let seal_rlp = rlp.at(i)?;
 			seal_fields.push(seal_rlp.as_raw().to_owned());
 		}
 

ethcore/src/snapshot/io.rs

@@ -60,9 +60,9 @@ impl rlp::Decodable for ChunkInfo {
 	fn decode<D: rlp::Decoder>(decoder: &D) -> Result<Self, rlp::DecoderError> {
 		let d = decoder.as_rlp();
 
-		let hash = try!(d.val_at(0));
-		let len = try!(d.val_at(1));
-		let off = try!(d.val_at(2));
+		let hash = d.val_at(0)?;
+		let len = d.val_at(1)?;
+		let off = d.val_at(2)?;
 		Ok(ChunkInfo(hash, len, off))
 	}
 }
@@ -88,7 +88,7 @@ impl PackedWriter {
 	/// Create a new "PackedWriter", to write into the file at the given path.
 	pub fn new(path: &Path) -> io::Result<Self> {
 		Ok(PackedWriter {
-			file: try!(File::create(path)),
+			file: File::create(path)?,
 			state_hashes: Vec::new(),
 			block_hashes: Vec::new(),
 			cur_len: 0,
@@ -98,7 +98,7 @@ impl PackedWriter {
 
 impl SnapshotWriter for PackedWriter {
 	fn write_state_chunk(&mut self, hash: H256, chunk: &[u8]) -> io::Result<()> {
-		try!(self.file.write_all(chunk));
+		self.file.write_all(chunk)?;
 
 		let len = chunk.len() as u64;
 		self.state_hashes.push(ChunkInfo(hash, len, self.cur_len));
@@ -108,7 +108,7 @@ impl SnapshotWriter for PackedWriter {
 	}
 
 	fn write_block_chunk(&mut self, hash: H256, chunk: &[u8]) -> io::Result<()> {
-		try!(self.file.write_all(chunk));
+		self.file.write_all(chunk)?;
 
 		let len = chunk.len() as u64;
 		self.block_hashes.push(ChunkInfo(hash, len, self.cur_len));
@@ -130,7 +130,7 @@ impl SnapshotWriter for PackedWriter {
 
 		let manifest_rlp = stream.out();
 
-		try!(self.file.write_all(&manifest_rlp));
+		self.file.write_all(&manifest_rlp)?;
 		let off = self.cur_len;
 		trace!(target: "snapshot_io", "writing manifest of len {} to offset {}", manifest_rlp.len(), off);
 
@@ -146,7 +146,7 @@ impl SnapshotWriter for PackedWriter {
 				(off >> 56) as u8,
 			];
 
-		try!(self.file.write_all(&off_bytes[..]));
+		self.file.write_all(&off_bytes[..])?;
 
 		Ok(())
 	}
@@ -161,7 +161,7 @@ impl LooseWriter {
 	/// Create a new LooseWriter which will write into the given directory,
 	/// creating it if it doesn't exist.
 	pub fn new(path: PathBuf) -> io::Result<Self> {
-		try!(fs::create_dir_all(&path));
+		fs::create_dir_all(&path)?;
 
 		Ok(LooseWriter {
 			dir: path,
@@ -173,8 +173,8 @@ impl LooseWriter {
 		let mut file_path = self.dir.clone();
 		file_path.push(hash.hex());
 
-		let mut file = try!(File::create(file_path));
-		try!(file.write_all(chunk));
+		let mut file = File::create(file_path)?;
+		file.write_all(chunk)?;
 
 		Ok(())
 	}
@@ -194,8 +194,8 @@ impl SnapshotWriter for LooseWriter {
 		let mut path = self.dir.clone();
 		path.push("MANIFEST");
 
-		let mut file = try!(File::create(path));
-		try!(file.write_all(&rlp[..]));
+		let mut file = File::create(path)?;
+		file.write_all(&rlp[..])?;
 
 		Ok(())
 	}
@@ -224,18 +224,18 @@ impl PackedReader {
 	/// This will fail if any io errors are encountered or the file
 	/// is not a valid packed snapshot.
 	pub fn new(path: &Path) -> Result<Option<Self>, ::error::Error> {
-		let mut file = try!(File::open(path));
-		let file_len = try!(file.metadata()).len();
+		let mut file = File::open(path)?;
+		let file_len = file.metadata()?.len();
 		if file_len < 8 {
 			// ensure we don't seek before beginning.
 			return Ok(None);
 		}
 
 
-		try!(file.seek(SeekFrom::End(-8)));
+		file.seek(SeekFrom::End(-8))?;
 		let mut off_bytes = [0u8; 8];
 
-		try!(file.read_exact(&mut off_bytes[..]));
+		file.read_exact(&mut off_bytes[..])?;
 
 		let manifest_off: u64 =
 			((off_bytes[7] as u64) << 56) +
@@ -252,20 +252,20 @@ impl PackedReader {
 
 		let	mut manifest_buf = vec![0; manifest_len as usize];
 
-		try!(file.seek(SeekFrom::Start(manifest_off)));
-		try!(file.read_exact(&mut manifest_buf));
+		file.seek(SeekFrom::Start(manifest_off))?;
+		file.read_exact(&mut manifest_buf)?;
 
 		let rlp = UntrustedRlp::new(&manifest_buf);
 
-		let state: Vec<ChunkInfo> = try!(rlp.val_at(0));
-		let blocks: Vec<ChunkInfo> = try!(rlp.val_at(1));
+		let state: Vec<ChunkInfo> = rlp.val_at(0)?;
+		let blocks: Vec<ChunkInfo> = rlp.val_at(1)?;
 
 		let manifest = ManifestData {
 			state_hashes: state.iter().map(|c| c.0).collect(),
 			block_hashes: blocks.iter().map(|c| c.0).collect(),
-			state_root: try!(rlp.val_at(2)),
-			block_number: try!(rlp.val_at(3)),
-			block_hash: try!(rlp.val_at(4)),
+			state_root: rlp.val_at(2)?,
+			block_number: rlp.val_at(3)?,
+			block_hash: rlp.val_at(4)?,
 		};
 
 		Ok(Some(PackedReader {
@@ -288,10 +288,10 @@ impl SnapshotReader for PackedReader {
 
 		let mut file = &self.file;
 
-		try!(file.seek(SeekFrom::Start(off)));
+		file.seek(SeekFrom::Start(off))?;
 		let mut buf = vec![0; len as usize];
 
-		try!(file.read_exact(&mut buf[..]));
+		file.read_exact(&mut buf[..])?;
 
 		Ok(buf)
 	}
@@ -310,10 +310,10 @@ impl LooseReader {
 		let mut manifest_buf = Vec::new();
 
 		dir.push("MANIFEST");
-		let mut manifest_file = try!(File::open(&dir));
-		try!(manifest_file.read_to_end(&mut manifest_buf));
+		let mut manifest_file = File::open(&dir)?;
+		manifest_file.read_to_end(&mut manifest_buf)?;
 
-		let manifest = try!(ManifestData::from_rlp(&manifest_buf[..]));
+		let manifest = ManifestData::from_rlp(&manifest_buf[..])?;
 
 		dir.pop();
 
@@ -334,9 +334,9 @@ impl SnapshotReader for LooseReader {
 		path.push(hash.hex());
 
 		let mut buf = Vec::new();
-		let mut file = try!(File::open(&path));
+		let mut file = File::open(&path)?;
 
-		try!(file.read_to_end(&mut buf));
+		file.read_to_end(&mut buf)?;
 
 		Ok(buf)
 	}

ethcore/src/snapshot/mod.rs

@@ -128,22 +128,22 @@ pub fn take_snapshot<W: SnapshotWriter + Send>(
 	writer: W,
 	p: &Progress
 ) -> Result<(), Error> {
-	let start_header = try!(chain.block_header(&block_at)
-		.ok_or(Error::InvalidStartingBlock(BlockId::Hash(block_at))));
+	let start_header = chain.block_header(&block_at)
+		.ok_or(Error::InvalidStartingBlock(BlockId::Hash(block_at)))?;
 	let state_root = start_header.state_root();
 	let number = start_header.number();
 
 	info!("Taking snapshot starting at block {}", number);
 
 	let writer = Mutex::new(writer);
-	let (state_hashes, block_hashes) = try!(scope(|scope| {
+	let (state_hashes, block_hashes) = scope(|scope| {
 		let block_guard = scope.spawn(|| chunk_blocks(chain, block_at, &writer, p));
 		let state_res = chunk_state(state_db, state_root, &writer, p);
 
 		state_res.and_then(|state_hashes| {
 			block_guard.join().map(|block_hashes| (state_hashes, block_hashes))
 		})
-	}));
+	})?;
 
 	info!("produced {} state chunks and {} block chunks.", state_hashes.len(), block_hashes.len());
 
@@ -155,7 +155,7 @@ pub fn take_snapshot<W: SnapshotWriter + Send>(
 		block_hash: block_at,
 	};
 
-	try!(writer.into_inner().finish(manifest_data));
+	writer.into_inner().finish(manifest_data)?;
 
 	p.done.store(true, Ordering::SeqCst);
 
@@ -186,9 +186,9 @@ impl<'a> BlockChunker<'a> {
 		for _ in 0..SNAPSHOT_BLOCKS {
 			if self.current_hash == genesis_hash { break }
 
-			let (block, receipts) = try!(self.chain.block(&self.current_hash)
+			let (block, receipts) = self.chain.block(&self.current_hash)
 				.and_then(|b| self.chain.block_receipts(&self.current_hash).map(|r| (b, r)))
-				.ok_or(Error::BlockNotFound(self.current_hash)));
+				.ok_or(Error::BlockNotFound(self.current_hash))?;
 
 			let view = BlockView::new(&block);
 			let abridged_rlp = AbridgedBlock::from_block_view(&view).into_inner();
@@ -204,7 +204,7 @@ impl<'a> BlockChunker<'a> {
 			// cut off the chunk if too large.
 
 			if new_loaded_size > PREFERRED_CHUNK_SIZE && !self.rlps.is_empty() {
-				try!(self.write_chunk(last));
+				self.write_chunk(last)?;
 				loaded_size = pair.len();
 			} else {
 				loaded_size = new_loaded_size;
@@ -217,7 +217,7 @@ impl<'a> BlockChunker<'a> {
 		}
 
 		if loaded_size != 0 {
-			try!(self.write_chunk(last));
+			self.write_chunk(last)?;
 		}
 
 		Ok(())
@@ -230,9 +230,9 @@ impl<'a> BlockChunker<'a> {
 	fn write_chunk(&mut self, last: H256) -> Result<(), Error> {
 		trace!(target: "snapshot", "prepared block chunk with {} blocks", self.rlps.len());
 
-		let (last_header, last_details) = try!(self.chain.block_header(&last)
+		let (last_header, last_details) = self.chain.block_header(&last)
 			.and_then(|n| self.chain.block_details(&last).map(|d| (n, d)))
-			.ok_or(Error::BlockNotFound(last)));
+			.ok_or(Error::BlockNotFound(last))?;
 
 		let parent_number = last_header.number() - 1;
 		let parent_hash = last_header.parent_hash();
@@ -254,7 +254,7 @@ impl<'a> BlockChunker<'a> {
 		let compressed = &self.snappy_buffer[..size];
 		let hash = compressed.sha3();
 
-		try!(self.writer.lock().write_block_chunk(hash, compressed));
+		self.writer.lock().write_block_chunk(hash, compressed)?;
 		trace!(target: "snapshot", "wrote block chunk. hash: {}, size: {}, uncompressed size: {}", hash.hex(), size, raw_data.len());
 
 		self.progress.size.fetch_add(size, Ordering::SeqCst);
@@ -282,7 +282,7 @@ pub fn chunk_blocks<'a>(chain: &'a BlockChain, start_hash: H256, writer: &Mutex<
 		progress: progress,
 	};
 
-	try!(chunker.chunk_all());
+	chunker.chunk_all()?;
 
 	Ok(chunker.hashes)
 }
@@ -310,7 +310,7 @@ impl<'a> StateChunker<'a> {
 		};
 
 		if self.cur_size + pair.len() >= PREFERRED_CHUNK_SIZE {
-			try!(self.write_chunk());
+			self.write_chunk()?;
 		}
 
 		self.cur_size += pair.len();
@@ -334,7 +334,7 @@ impl<'a> StateChunker<'a> {
 		let compressed = &self.snappy_buffer[..compressed_size];
 		let hash = compressed.sha3();
 
-		try!(self.writer.lock().write_state_chunk(hash, compressed));
+		self.writer.lock().write_state_chunk(hash, compressed)?;
 		trace!(target: "snapshot", "wrote state chunk. size: {}, uncompressed size: {}", compressed_size, raw_data.len());
 
 		self.progress.accounts.fetch_add(num_entries, Ordering::SeqCst);
@@ -353,7 +353,7 @@ impl<'a> StateChunker<'a> {
 /// Returns a list of hashes of chunks created, or any error it may
 /// have encountered.
 pub fn chunk_state<'a>(db: &HashDB, root: &H256, writer: &Mutex<SnapshotWriter + 'a>, progress: &'a Progress) -> Result<Vec<H256>, Error> {
-	let account_trie = try!(TrieDB::new(db, &root));
+	let account_trie = TrieDB::new(db, &root)?;
 
 	let mut chunker = StateChunker {
 		hashes: Vec::new(),
@@ -367,19 +367,19 @@ pub fn chunk_state<'a>(db: &HashDB, root: &H256, writer: &Mutex<SnapshotWriter +
 	let mut used_code = HashSet::new();
 
 	// account_key here is the address' hash.
-	for item in try!(account_trie.iter()) {
-		let (account_key, account_data) = try!(item);
+	for item in account_trie.iter()? {
+		let (account_key, account_data) = item?;
 		let account = Account::from_thin_rlp(&*account_data);
 		let account_key_hash = H256::from_slice(&account_key);
 
 		let account_db = AccountDB::from_hash(db, account_key_hash);
 
-		let fat_rlp = try!(account.to_fat_rlp(&account_db, &mut used_code));
-		try!(chunker.push(account_key, fat_rlp));
+		let fat_rlp = account.to_fat_rlp(&account_db, &mut used_code)?;
+		chunker.push(account_key, fat_rlp)?;
 	}
 
 	if chunker.cur_size != 0 {
-		try!(chunker.write_chunk());
+		chunker.write_chunk()?;
 	}
 
 	Ok(chunker.hashes)
@@ -415,13 +415,13 @@ impl StateRebuilder {
 		// initialize the pairs vector with empty values so we have slots to write into.
 		pairs.resize(rlp.item_count(), (H256::new(), Vec::new()));
 
-		let status = try!(rebuild_accounts(
+		let status = rebuild_accounts(
 			self.db.as_hashdb_mut(),
 			rlp,
 			&mut pairs,
 			&self.known_code,
 			flag
-		));
+		)?;
 
 		for (addr_hash, code_hash) in status.missing_code {
 			self.missing_code.entry(code_hash).or_insert_with(Vec::new).push(addr_hash);
@@ -442,7 +442,7 @@ impl StateRebuilder {
 		// batch trie writes
 		{
 			let mut account_trie = if self.state_root != SHA3_NULL_RLP {
-				try!(TrieDBMut::from_existing(self.db.as_hashdb_mut(), &mut self.state_root))
+				TrieDBMut::from_existing(self.db.as_hashdb_mut(), &mut self.state_root)?
 			} else {
 				TrieDBMut::new(self.db.as_hashdb_mut(), &mut self.state_root)
 			};
@@ -453,14 +453,14 @@ impl StateRebuilder {
 				if &thin_rlp[..] != &empty_rlp[..] {
 					self.bloom.set(&*hash);
 				}
-				try!(account_trie.insert(&hash, &thin_rlp));
+				account_trie.insert(&hash, &thin_rlp)?;
 			}
 		}
 
 		let bloom_journal = self.bloom.drain_journal();
 		let mut batch = backing.transaction();
-		try!(StateDB::commit_bloom(&mut batch, bloom_journal));
-		try!(self.db.inject(&mut batch));
+		StateDB::commit_bloom(&mut batch, bloom_journal)?;
+		self.db.inject(&mut batch)?;
 		backing.write_buffered(batch);
 		trace!(target: "snapshot", "current state root: {:?}", self.state_root);
 		Ok(())
@@ -500,15 +500,15 @@ fn rebuild_accounts(
 	for (account_rlp, out) in account_fat_rlps.into_iter().zip(out_chunk) {
 		if !abort_flag.load(Ordering::SeqCst) { return Err(Error::RestorationAborted.into()) }
 
-		let hash: H256 = try!(account_rlp.val_at(0));
-		let fat_rlp = try!(account_rlp.at(1));
+		let hash: H256 = account_rlp.val_at(0)?;
+		let fat_rlp = account_rlp.at(1)?;
 
 		let thin_rlp = {
 
 			// fill out the storage trie and code while decoding.
 			let (acc, maybe_code) = {
 				let mut acct_db = AccountDBMut::from_hash(db, hash);
-				try!(Account::from_fat_rlp(&mut acct_db, fat_rlp))
+				Account::from_fat_rlp(&mut acct_db, fat_rlp)?
 			};
 
 			let code_hash = acc.code_hash().clone();
@@ -521,9 +521,9 @@ fn rebuild_accounts(
 						match known_code.get(&code_hash) {
 							Some(&first_with) => {
 								// if so, load it from the database.
-								let code = try!(AccountDB::from_hash(db, first_with)
+								let code = AccountDB::from_hash(db, first_with)
 									.get(&code_hash)
-									.ok_or_else(|| Error::MissingCode(vec![first_with])));
+									.ok_or_else(|| Error::MissingCode(vec![first_with]))?;
 
 								// and write it again under a different mangled key
 								AccountDBMut::from_hash(db, hash).emplace(code_hash, code);
@@ -586,7 +586,7 @@ impl BlockRebuilder {
 		Ok(BlockRebuilder {
 			chain: chain,
 			db: db,
-			rng: try!(OsRng::new()),
+			rng: OsRng::new()?,
 			disconnected: Vec::new(),
 			best_number: manifest.block_number,
 			best_hash: manifest.block_hash,
@@ -613,22 +613,22 @@ impl BlockRebuilder {
 		}
 
 		// todo: assert here that these values are consistent with chunks being in order.
-		let mut cur_number = try!(rlp.val_at::<u64>(0)) + 1;
-		let mut parent_hash = try!(rlp.val_at::<H256>(1));
-		let parent_total_difficulty = try!(rlp.val_at::<U256>(2));
+		let mut cur_number = rlp.val_at::<u64>(0)? + 1;
+		let mut parent_hash = rlp.val_at::<H256>(1)?;
+		let parent_total_difficulty = rlp.val_at::<U256>(2)?;
 
 		for idx in 3..item_count {
 			if !abort_flag.load(Ordering::SeqCst) { return Err(Error::RestorationAborted.into()) }
 
-			let pair = try!(rlp.at(idx));
-			let abridged_rlp = try!(pair.at(0)).as_raw().to_owned();
+			let pair = rlp.at(idx)?;
+			let abridged_rlp = pair.at(0)?.as_raw().to_owned();
 			let abridged_block = AbridgedBlock::from_raw(abridged_rlp);
-			let receipts: Vec<::receipt::Receipt> = try!(pair.val_at(1));
+			let receipts: Vec<::receipt::Receipt> = pair.val_at(1)?;
 			let receipts_root = ordered_trie_root(
-				try!(pair.at(1)).iter().map(|r| r.as_raw().to_owned())
+				pair.at(1)?.iter().map(|r| r.as_raw().to_owned())
 			);
 
-			let block = try!(abridged_block.to_block(parent_hash, cur_number, receipts_root));
+			let block = abridged_block.to_block(parent_hash, cur_number, receipts_root)?;
 			let block_bytes = block.rlp_bytes(With);
 			let is_best = cur_number == self.best_number;
 
@@ -642,14 +642,14 @@ impl BlockRebuilder {
 				}
 			}
 
-			try!(verify_old_block(
+			verify_old_block(
 				&mut self.rng,
 				&block.header,
 				engine,
 				&self.chain,
 				Some(&block_bytes),
 				is_best
-			));
+			)?;
 
 			let mut batch = self.db.transaction();
 
@@ -693,7 +693,7 @@ impl BlockRebuilder {
 		let best_number = self.best_number;
 		for num in (0..self.fed_blocks).map(|x| best_number - x) {
 
-			let hash = try!(self.chain.block_hash(num).ok_or(Error::IncompleteChain));
+			let hash = self.chain.block_hash(num).ok_or(Error::IncompleteChain)?;
 
 			if let Some(canon_hash) = canonical.get(&num).cloned() {
 				if canon_hash != hash {

ethcore/src/snapshot/service.rs

@@ -97,11 +97,11 @@ impl Restoration {
 		let state_chunks = manifest.state_hashes.iter().cloned().collect();
 		let block_chunks = manifest.block_hashes.iter().cloned().collect();
 
-		let raw_db = Arc::new(try!(Database::open(params.db_config, &*params.db_path.to_string_lossy())
-			.map_err(UtilError::SimpleString)));
+		let raw_db = Arc::new(Database::open(params.db_config, &*params.db_path.to_string_lossy())
+			.map_err(UtilError::SimpleString)?);
 
 		let chain = BlockChain::new(Default::default(), params.genesis, raw_db.clone(), params.engine);
-		let blocks = try!(BlockRebuilder::new(chain, raw_db.clone(), &manifest));
+		let blocks = BlockRebuilder::new(chain, raw_db.clone(), &manifest)?;
 
 		let root = manifest.state_root.clone();
 		Ok(Restoration {
@@ -122,12 +122,12 @@ impl Restoration {
 	// feeds a state chunk, aborts early if `flag` becomes false.
 	fn feed_state(&mut self, hash: H256, chunk: &[u8], flag: &AtomicBool) -> Result<(), Error> {
 		if self.state_chunks_left.remove(&hash) {
-			let len = try!(snappy::decompress_into(chunk, &mut self.snappy_buffer));
+			let len = snappy::decompress_into(chunk, &mut self.snappy_buffer)?;
 
-			try!(self.state.feed(&self.snappy_buffer[..len], flag));
+			self.state.feed(&self.snappy_buffer[..len], flag)?;
 
 			if let Some(ref mut writer) = self.writer.as_mut() {
-				try!(writer.write_state_chunk(hash, chunk));
+				writer.write_state_chunk(hash, chunk)?;
 			}
 		}
 
@@ -137,11 +137,11 @@ impl Restoration {
 	// feeds a block chunk
 	fn feed_blocks(&mut self, hash: H256, chunk: &[u8], engine: &Engine, flag: &AtomicBool) -> Result<(), Error> {
 		if self.block_chunks_left.remove(&hash) {
-			let len = try!(snappy::decompress_into(chunk, &mut self.snappy_buffer));
+			let len = snappy::decompress_into(chunk, &mut self.snappy_buffer)?;
 
-			try!(self.blocks.feed(&self.snappy_buffer[..len], engine, flag));
+			self.blocks.feed(&self.snappy_buffer[..len], engine, flag)?;
 			if let Some(ref mut writer) = self.writer.as_mut() {
-				 try!(writer.write_block_chunk(hash, chunk));
+				 writer.write_block_chunk(hash, chunk)?;
 			}
 		}
 
@@ -167,13 +167,13 @@ impl Restoration {
 		}
 
 		// check for missing code.
-		try!(self.state.check_missing());
+		self.state.check_missing()?;
 
 		// connect out-of-order chunks and verify chain integrity.
-		try!(self.blocks.finalize(self.canonical_hashes));
+		self.blocks.finalize(self.canonical_hashes)?;
 
 		if let Some(writer) = self.writer {
-			try!(writer.finish(self.manifest));
+			writer.finish(self.manifest)?;
 		}
 
 		self.guard.disarm();
@@ -315,7 +315,7 @@ impl Service {
 	fn replace_client_db(&self) -> Result<(), Error> {
 		let our_db = self.restoration_db();
 
-		try!(self.db_restore.restore_db(&*our_db.to_string_lossy()));
+		self.db_restore.restore_db(&*our_db.to_string_lossy())?;
 		Ok(())
 	}
 
@@ -351,7 +351,7 @@ impl Service {
 
 		let _ = fs::remove_dir_all(&temp_dir);
 
-		let writer = try!(LooseWriter::new(temp_dir.clone()));
+		let writer = LooseWriter::new(temp_dir.clone())?;
 
 		let guard = Guard::new(temp_dir.clone());
 		let res = client.take_snapshot(writer, BlockId::Number(num), &self.progress);
@@ -378,12 +378,12 @@ impl Service {
 		*reader = None;
 
 		if snapshot_dir.exists() {
-			try!(fs::remove_dir_all(&snapshot_dir));
+			fs::remove_dir_all(&snapshot_dir)?;
 		}
 
-		try!(fs::rename(temp_dir, &snapshot_dir));
+		fs::rename(temp_dir, &snapshot_dir)?;
 
-		*reader = Some(try!(LooseReader::new(snapshot_dir)));
+		*reader = Some(LooseReader::new(snapshot_dir)?);
 
 		guard.disarm();
 		Ok(())
@@ -410,11 +410,11 @@ impl Service {
 			}
 		}
 
-		try!(fs::create_dir_all(&rest_dir));
+		fs::create_dir_all(&rest_dir)?;
 
 		// make new restoration.
 		let writer = match recover {
-			true => Some(try!(LooseWriter::new(self.temp_recovery_dir()))),
+			true => Some(LooseWriter::new(self.temp_recovery_dir())?),
 			false => None
 		};
 
@@ -432,7 +432,7 @@ impl Service {
 		let state_chunks = params.manifest.state_hashes.len();
 		let block_chunks = params.manifest.block_hashes.len();
 
-		*res = Some(try!(Restoration::new(params)));
+		*res = Some(Restoration::new(params)?);
 
 		*self.status.lock() = RestorationStatus::Ongoing {
 			state_chunks: state_chunks as u32,
@@ -454,8 +454,8 @@ impl Service {
 		let recover = rest.as_ref().map_or(false, |rest| rest.writer.is_some());
 
 		// destroy the restoration before replacing databases and snapshot.
-		try!(rest.take().map(Restoration::finalize).unwrap_or(Ok(())));
-		try!(self.replace_client_db());
+		rest.take().map(Restoration::finalize).unwrap_or(Ok(()))?;
+		self.replace_client_db()?;
 
 		if recover {
 			let mut reader = self.reader.write();
@@ -465,13 +465,13 @@ impl Service {
 
 			if snapshot_dir.exists() {
 				trace!(target: "snapshot", "removing old snapshot dir at {}", snapshot_dir.to_string_lossy());
-				try!(fs::remove_dir_all(&snapshot_dir));
+				fs::remove_dir_all(&snapshot_dir)?;
 			}
 
 			trace!(target: "snapshot", "copying restored snapshot files over");
-			try!(fs::rename(self.temp_recovery_dir(), &snapshot_dir));
+			fs::rename(self.temp_recovery_dir(), &snapshot_dir)?;
 
-			*reader = Some(try!(LooseReader::new(snapshot_dir)));
+			*reader = Some(LooseReader::new(snapshot_dir)?);
 		}
 
 		let _ = fs::remove_dir_all(self.restoration_dir());
@@ -510,7 +510,7 @@ impl Service {
 
 							match is_done {
 								true => {
-									try!(db.flush().map_err(::util::UtilError::SimpleString));
+									db.flush().map_err(::util::UtilError::SimpleString)?;
 									drop(db);
 									return self.finalize_restoration(&mut *restoration);
 								},

ethcore/src/spec/spec.rs

@@ -259,7 +259,7 @@ impl Spec {
 		{
 			let mut t = factories.trie.create(db.as_hashdb_mut(), &mut root);
 			for (address, account) in self.genesis_state.get().iter() {
-				try!(t.insert(&**address, &account.rlp()));
+				t.insert(&**address, &account.rlp())?;
 			}
 		}
 

ethcore/src/state/account.rs

@@ -450,8 +450,8 @@ impl Account {
 
 		let mut recorder = TrieRecorder::with_depth(from_level);
 
-		let trie = try!(TrieDB::new(db, &self.storage_root));
-		let _ = try!(trie.get_recorded(&storage_key, &mut recorder));
+		let trie = TrieDB::new(db, &self.storage_root)?;
+		let _ = trie.get_recorded(&storage_key, &mut recorder)?;
 
 		Ok(recorder.drain().into_iter().map(|r| r.data).collect())
 	}

ethcore/src/state/mod.rs

@@ -515,11 +515,11 @@ impl State {
 
 		let options = TransactOptions { tracing: tracing, vm_tracing: false, check_nonce: true };
 		let vm_factory = self.factories.vm.clone();
-		let e = try!(Executive::new(self, env_info, engine, &vm_factory).transact(t, options));
+		let e = Executive::new(self, env_info, engine, &vm_factory).transact(t, options)?;
 
 		// TODO uncomment once to_pod() works correctly.
 //		trace!("Applied transaction. Diff:\n{}\n", state_diff::diff_pod(&old, &self.to_pod()));
-		try!(self.commit());
+		self.commit()?;
 		let receipt = Receipt::new(self.root().clone(), e.cumulative_gas_used, e.logs);
 		trace!(target: "state", "Transaction receipt: {:?}", receipt);
 		Ok(ApplyOutcome{receipt: receipt, trace: e.trace})
@@ -551,15 +551,15 @@ impl State {
 		}
 
 		{
-			let mut trie = try!(factories.trie.from_existing(db.as_hashdb_mut(), root));
+			let mut trie = factories.trie.from_existing(db.as_hashdb_mut(), root)?;
 			for (address, ref mut a) in accounts.iter_mut().filter(|&(_, ref a)| a.is_dirty()) {
 				a.state = AccountState::Committed;
 				match a.account {
 					Some(ref mut account) => {
-						try!(trie.insert(address, &account.rlp()));
+						trie.insert(address, &account.rlp())?;
 					},
 					None => {
-						try!(trie.remove(address));
+						trie.remove(address)?;
 					},
 				}
 			}
@@ -771,8 +771,8 @@ impl State {
 	/// `account_key` == sha3(address)
 	pub fn prove_account(&self, account_key: H256, from_level: u32) -> Result<Vec<Bytes>, Box<TrieError>> {
 		let mut recorder = TrieRecorder::with_depth(from_level);
-		let trie = try!(TrieDB::new(self.db.as_hashdb(), &self.root));
-		let _  = try!(trie.get_recorded(&account_key, &mut recorder));
+		let trie = TrieDB::new(self.db.as_hashdb(), &self.root)?;
+		let _  = trie.get_recorded(&account_key, &mut recorder)?;
 
 		Ok(recorder.drain().into_iter().map(|r| r.data).collect())
 	}
@@ -785,8 +785,8 @@ impl State {
 	pub fn prove_storage(&self, account_key: H256, storage_key: H256, from_level: u32) -> Result<Vec<Bytes>, Box<TrieError>> {
 		// TODO: probably could look into cache somehow but it's keyed by
 		// address, not sha3(address).
-		let trie = try!(TrieDB::new(self.db.as_hashdb(), &self.root));
-		let acc = match try!(trie.get(&account_key)) {
+		let trie = TrieDB::new(self.db.as_hashdb(), &self.root)?;
+		let acc = match trie.get(&account_key)? {
 			Some(rlp) => Account::from_rlp(&rlp),
 			None => return Ok(Vec::new()),
 		};
@@ -798,8 +798,8 @@ impl State {
 	/// Get code by address hash.
 	/// Only works when backed by a secure trie.
 	pub fn code_by_address_hash(&self, account_key: H256) -> Result<Option<Bytes>, Box<TrieError>> {
-		let trie = try!(TrieDB::new(self.db.as_hashdb(), &self.root));
-		let mut acc = match try!(trie.get(&account_key)) {
+		let trie = TrieDB::new(self.db.as_hashdb(), &self.root)?;
+		let mut acc = match trie.get(&account_key)? {
 			Some(rlp) => Account::from_rlp(&rlp),
 			None => return Ok(None),
 		};

ethcore/src/state_db.rs

@@ -195,9 +195,9 @@ impl StateDB {
 	pub fn journal_under(&mut self, batch: &mut DBTransaction, now: u64, id: &H256) -> Result<u32, UtilError> {
 		{
  			let mut bloom_lock = self.account_bloom.lock();
- 			try!(Self::commit_bloom(batch, bloom_lock.drain_journal()));
+ 			Self::commit_bloom(batch, bloom_lock.drain_journal())?;
  		}
-		let records = try!(self.db.journal_under(batch, now, id));
+		let records = self.db.journal_under(batch, now, id)?;
 		self.commit_hash = Some(id.clone());
 		self.commit_number = Some(now);
 		Ok(records)

ethcore/src/trace/bloom.rs

@@ -73,7 +73,7 @@ impl Encodable for BlockTracesBloom {
 
 impl Decodable for BlockTracesBloomGroup {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
-		let blooms = try!(Decodable::decode(decoder));
+		let blooms = Decodable::decode(decoder)?;
 		let group = BlockTracesBloomGroup {
 			blooms: blooms
 		};

ethcore/src/types/account_diff.rs

@@ -80,9 +80,9 @@ pub enum Existance {
 impl fmt::Display for Existance {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		match *self {
-			Existance::Born => try!(write!(f, "+++")),
-			Existance::Alive => try!(write!(f, "***")),
-			Existance::Died => try!(write!(f, "XXX")),
+			Existance::Born => write!(f, "+++")?,
+			Existance::Alive => write!(f, "***")?,
+			Existance::Died => write!(f, "XXX")?,
 		}
 		Ok(())
 	}
@@ -117,24 +117,24 @@ impl fmt::Display for AccountDiff {
 		use util::bytes::ToPretty;
 
 		match self.nonce {
-			Diff::Born(ref x) => try!(write!(f, "  non {}", x)),
-			Diff::Changed(ref pre, ref post) => try!(write!(f, "#{} ({} {} {})", post, pre, if pre > post {"-"} else {"+"}, *max(pre, post) - *	min(pre, post))),
+			Diff::Born(ref x) => write!(f, "  non {}", x)?,
+			Diff::Changed(ref pre, ref post) => write!(f, "#{} ({} {} {})", post, pre, if pre > post {"-"} else {"+"}, *max(pre, post) - *	min(pre, post))?,
 			_ => {},
 		}
 		match self.balance {
-			Diff::Born(ref x) => try!(write!(f, "  bal {}", x)),
-			Diff::Changed(ref pre, ref post) => try!(write!(f, "${} ({} {} {})", post, pre, if pre > post {"-"} else {"+"}, *max(pre, post) - *min(pre, post))),
+			Diff::Born(ref x) => write!(f, "  bal {}", x)?,
+			Diff::Changed(ref pre, ref post) => write!(f, "${} ({} {} {})", post, pre, if pre > post {"-"} else {"+"}, *max(pre, post) - *min(pre, post))?,
 			_ => {},
 		}
 		if let Diff::Born(ref x) = self.code {
-			try!(write!(f, "  code {}", x.pretty()));
+			write!(f, "  code {}", x.pretty())?;
 		}
-		try!(write!(f, "\n"));
+		write!(f, "\n")?;
 		for (k, dv) in &self.storage {
 			match *dv {
-				Diff::Born(ref v) => try!(write!(f, "    +  {} => {}\n", interpreted_hash(k), interpreted_hash(v))),
-				Diff::Changed(ref pre, ref post) => try!(write!(f, "    *  {} => {} (was {})\n", interpreted_hash(k), interpreted_hash(post), interpreted_hash(pre))),
-				Diff::Died(_) => try!(write!(f, "    X  {}\n", interpreted_hash(k))),
+				Diff::Born(ref v) => write!(f, "    +  {} => {}\n", interpreted_hash(k), interpreted_hash(v))?,
+				Diff::Changed(ref pre, ref post) => write!(f, "    *  {} => {} (was {})\n", interpreted_hash(k), interpreted_hash(post), interpreted_hash(pre))?,
+				Diff::Died(_) => write!(f, "    X  {}\n", interpreted_hash(k))?,
 				_ => {},
 			}
 		}

ethcore/src/types/log_entry.rs

@@ -50,9 +50,9 @@ impl Decodable for LogEntry {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		let entry = LogEntry {
-			address: try!(d.val_at(0)),
-			topics: try!(d.val_at(1)),
-			data: try!(d.val_at(2)),
+			address: d.val_at(0)?,
+			topics: d.val_at(1)?,
+			data: d.val_at(2)?,
 		};
 		Ok(entry)
 	}

ethcore/src/types/receipt.rs

@@ -64,10 +64,10 @@ impl Decodable for Receipt {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		let receipt = Receipt {
-			state_root: try!(d.val_at(0)),
-			gas_used: try!(d.val_at(1)),
-			log_bloom: try!(d.val_at(2)),
-			logs: try!(d.val_at(3)),
+			state_root: d.val_at(0)?,
+			gas_used: d.val_at(1)?,
+			log_bloom: d.val_at(2)?,
+			logs: d.val_at(3)?,
 		};
 		Ok(receipt)
 	}

ethcore/src/types/snapshot_manifest.rs

@@ -53,11 +53,11 @@ impl ManifestData {
 	pub fn from_rlp(raw: &[u8]) -> Result<Self, DecoderError> {
 		let decoder = UntrustedRlp::new(raw);
 
-		let state_hashes: Vec<H256> = try!(decoder.val_at(0));
-		let block_hashes: Vec<H256> = try!(decoder.val_at(1));
-		let state_root: H256 = try!(decoder.val_at(2));
-		let block_number: u64 = try!(decoder.val_at(3));
-		let block_hash: H256 = try!(decoder.val_at(4));
+		let state_hashes: Vec<H256> = decoder.val_at(0)?;
+		let block_hashes: Vec<H256> = decoder.val_at(1)?;
+		let state_root: H256 = decoder.val_at(2)?;
+		let block_number: u64 = decoder.val_at(3)?;
+		let block_hash: H256 = decoder.val_at(4)?;
 
 		Ok(ManifestData {
 			state_hashes: state_hashes,

ethcore/src/types/state_diff.rs

@@ -41,7 +41,7 @@ impl StateDiff {
 impl fmt::Display for StateDiff {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		for (add, acc) in &self.raw {
-			try!(write!(f, "{} {}: {}", acc.existance(), add, acc));
+			write!(f, "{} {}: {}", acc.existance(), add, acc)?;
 		}
 		Ok(())
 	}

ethcore/src/types/trace_types/error.rs

@@ -86,7 +86,7 @@ impl Encodable for Error {
 impl Decodable for Error {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		use self::Error::*;
-		let value: u8 = try!(decoder.as_rlp().as_val());
+		let value: u8 = decoder.as_rlp().as_val()?;
 		match value {
 			0 => Ok(OutOfGas),
 			1 => Ok(BadJumpDestination),

ethcore/src/types/trace_types/flat.rs

@@ -66,11 +66,11 @@ impl Encodable for FlatTrace {
 impl Decodable for FlatTrace {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
-		let v: Vec<usize> = try!(d.val_at(3));
+		let v: Vec<usize> = d.val_at(3)?;
 		let res = FlatTrace {
-			action: try!(d.val_at(0)),
-			result: try!(d.val_at(1)),
-			subtraces: try!(d.val_at(2)),
+			action: d.val_at(0)?,
+			result: d.val_at(1)?,
+			subtraces: d.val_at(2)?,
 			trace_address: v.into_iter().collect(),
 		};
 
@@ -109,7 +109,7 @@ impl Encodable for FlatTransactionTraces {
 
 impl Decodable for FlatTransactionTraces {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
-		Ok(FlatTransactionTraces(try!(Decodable::decode(decoder))))
+		Ok(FlatTransactionTraces(Decodable::decode(decoder)?))
 	}
 }
 
@@ -150,7 +150,7 @@ impl Encodable for FlatBlockTraces {
 
 impl Decodable for FlatBlockTraces {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
-		Ok(FlatBlockTraces(try!(Decodable::decode(decoder))))
+		Ok(FlatBlockTraces(Decodable::decode(decoder)?))
 	}
 }
 

ethcore/src/types/trace_types/trace.rs

@@ -48,8 +48,8 @@ impl Decodable for CallResult {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		let res = CallResult {
-			gas_used: try!(d.val_at(0)),
-			output: try!(d.val_at(1)),
+			gas_used: d.val_at(0)?,
+			output: d.val_at(1)?,
 		};
 
 		Ok(res)
@@ -81,9 +81,9 @@ impl Decodable for CreateResult {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		let res = CreateResult {
-			gas_used: try!(d.val_at(0)),
-			code: try!(d.val_at(1)),
-			address: try!(d.val_at(2)),
+			gas_used: d.val_at(0)?,
+			code: d.val_at(1)?,
+			address: d.val_at(2)?,
 		};
 
 		Ok(res)
@@ -144,12 +144,12 @@ impl Decodable for Call {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		let res = Call {
-			from: try!(d.val_at(0)),
-			to: try!(d.val_at(1)),
-			value: try!(d.val_at(2)),
-			gas: try!(d.val_at(3)),
-			input: try!(d.val_at(4)),
-			call_type: try!(d.val_at(5)),
+			from: d.val_at(0)?,
+			to: d.val_at(1)?,
+			value: d.val_at(2)?,
+			gas: d.val_at(3)?,
+			input: d.val_at(4)?,
+			call_type: d.val_at(5)?,
 		};
 
 		Ok(res)
@@ -204,10 +204,10 @@ impl Decodable for Create {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		let res = Create {
-			from: try!(d.val_at(0)),
-			value: try!(d.val_at(1)),
-			gas: try!(d.val_at(2)),
-			init: try!(d.val_at(3)),
+			from: d.val_at(0)?,
+			value: d.val_at(1)?,
+			gas: d.val_at(2)?,
+			init: d.val_at(3)?,
 		};
 
 		Ok(res)
@@ -255,9 +255,9 @@ impl Decodable for Suicide {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		let res = Suicide {
-			address: try!(d.val_at(0)),
-			refund_address: try!(d.val_at(1)),
-			balance: try!(d.val_at(2)),
+			address: d.val_at(0)?,
+			refund_address: d.val_at(1)?,
+			balance: d.val_at(2)?,
 		};
 
 		Ok(res)
@@ -300,7 +300,7 @@ impl Encodable for Action {
 impl Decodable for Action {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
-		let action_type: u8 = try!(d.val_at(0));
+		let action_type: u8 = d.val_at(0)?;
 		match action_type {
 			0 => d.val_at(1).map(Action::Call),
 			1 => d.val_at(1).map(Action::Create),
@@ -371,7 +371,7 @@ impl Encodable for Res {
 impl Decodable for Res {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
-		let action_type: u8 = try!(d.val_at(0));
+		let action_type: u8 = d.val_at(0)?;
 		match action_type {
 			0 => d.val_at(1).map(Res::Call),
 			1 => d.val_at(1).map(Res::Create),
@@ -415,8 +415,8 @@ impl Decodable for MemoryDiff {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		Ok(MemoryDiff {
-			offset: try!(d.val_at(0)),
-			data: try!(d.val_at(1)),
+			offset: d.val_at(0)?,
+			data: d.val_at(1)?,
 		})
 	}
 }
@@ -443,8 +443,8 @@ impl Decodable for StorageDiff {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		Ok(StorageDiff {
-			location: try!(d.val_at(0)),
-			value: try!(d.val_at(1)),
+			location: d.val_at(0)?,
+			value: d.val_at(1)?,
 		})
 	}
 }
@@ -477,10 +477,10 @@ impl Decodable for VMExecutedOperation {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		Ok(VMExecutedOperation {
-			gas_used: try!(d.val_at(0)),
-			stack_push: try!(d.val_at(1)),
-			mem_diff: try!(d.val_at(2)),
-			store_diff: try!(d.val_at(3)),
+			gas_used: d.val_at(0)?,
+			stack_push: d.val_at(1)?,
+			mem_diff: d.val_at(2)?,
+			store_diff: d.val_at(3)?,
 		})
 	}
 }
@@ -513,10 +513,10 @@ impl Decodable for VMOperation {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		let res = VMOperation {
-			pc: try!(d.val_at(0)),
-			instruction: try!(d.val_at(1)),
-			gas_cost: try!(d.val_at(2)),
-			executed: try!(d.val_at(3)),
+			pc: d.val_at(0)?,
+			instruction: d.val_at(1)?,
+			gas_cost: d.val_at(2)?,
+			executed: d.val_at(3)?,
 		};
 
 		Ok(res)
@@ -552,10 +552,10 @@ impl Decodable for VMTrace {
 	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
 		let d = decoder.as_rlp();
 		let res = VMTrace {
-			parent_step: try!(d.val_at(0)),
-			code: try!(d.val_at(1)),
-			operations: try!(d.val_at(2)),
-			subs: try!(d.val_at(3)),
+			parent_step: d.val_at(0)?,
+			code: d.val_at(1)?,
+			operations: d.val_at(2)?,
+			subs: d.val_at(3)?,
 		};
 
 		Ok(res)

ethcore/src/types/transaction.rs

@@ -48,7 +48,7 @@ impl Decodable for Action {
 		if rlp.is_empty() {
 			Ok(Action::Create)
 		} else {
-			Ok(Action::Call(try!(rlp.as_val())))
+			Ok(Action::Call(rlp.as_val()?))
 		}
 	}
 }
@@ -247,16 +247,16 @@ impl Decodable for SignedTransaction {
 		}
 		Ok(SignedTransaction {
 			unsigned: Transaction {
-				nonce: try!(d.val_at(0)),
-				gas_price: try!(d.val_at(1)),
-				gas: try!(d.val_at(2)),
-				action: try!(d.val_at(3)),
-				value: try!(d.val_at(4)),
-				data: try!(d.val_at(5)),
+				nonce: d.val_at(0)?,
+				gas_price: d.val_at(1)?,
+				gas: d.val_at(2)?,
+				action: d.val_at(3)?,
+				value: d.val_at(4)?,
+				data: d.val_at(5)?,
 			},
-			v: try!(d.val_at(6)),
-			r: try!(d.val_at(7)),
-			s: try!(d.val_at(8)),
+			v: d.val_at(6)?,
+			r: d.val_at(7)?,
+			s: d.val_at(8)?,
 			hash: Cell::new(None),
 			sender: Cell::new(None),
 		})
@@ -338,7 +338,7 @@ impl SignedTransaction {
 		match sender {
 			Some(s) => Ok(s),
 			None => {
-				let s = public_to_address(&try!(self.public_key()));
+				let s = public_to_address(&self.public_key()?);
 				self.sender.set(Some(s));
 				Ok(s)
 			}
@@ -347,7 +347,7 @@ impl SignedTransaction {
 
 	/// Returns the public key of the sender.
 	pub fn public_key(&self) -> Result<Public, Error> {
-		Ok(try!(recover(&self.signature(), &self.unsigned.hash(self.network_id()))))
+		Ok(recover(&self.signature(), &self.unsigned.hash(self.network_id()))?)
 	}
 
 	/// Do basic validation, checking for valid signature and minimum gas,
@@ -363,7 +363,7 @@ impl SignedTransaction {
 			Some(1) if allow_network_id_of_one => {},
 			_ => return Err(TransactionError::InvalidNetworkId.into()),
 		}
-		try!(self.sender());
+		self.sender()?;
 		if self.gas < U256::from(self.gas_required(&schedule)) {
 			Err(TransactionError::InvalidGasLimit(::util::OutOfBounds{min: Some(U256::from(self.gas_required(&schedule))), max: None, found: self.gas}).into())
 		} else {

ethcore/src/verification/verification.rs

@@ -51,19 +51,19 @@ impl HeapSizeOf for PreverifiedBlock {
 
 /// Phase 1 quick block verification. Only does checks that are cheap. Operates on a single block
 pub fn verify_block_basic(header: &Header, bytes: &[u8], engine: &Engine) -> Result<(), Error> {
-	try!(verify_header_params(&header, engine));
-	try!(verify_block_integrity(bytes, &header.transactions_root(), &header.uncles_hash()));
-	try!(engine.verify_block_basic(&header, Some(bytes)));
-	for u in try!(UntrustedRlp::new(bytes).at(2)).iter().map(|rlp| rlp.as_val::<Header>()) {
-		let u = try!(u);
-		try!(verify_header_params(&u, engine));
-		try!(engine.verify_block_basic(&u, None));
+	verify_header_params(&header, engine)?;
+	verify_block_integrity(bytes, &header.transactions_root(), &header.uncles_hash())?;
+	engine.verify_block_basic(&header, Some(bytes))?;
+	for u in UntrustedRlp::new(bytes).at(2)?.iter().map(|rlp| rlp.as_val::<Header>()) {
+		let u = u?;
+		verify_header_params(&u, engine)?;
+		engine.verify_block_basic(&u, None)?;
 	}
 	// Verify transactions.
 	// TODO: either use transaction views or cache the decoded transactions.
 	let v = BlockView::new(bytes);
 	for t in v.transactions() {
-		try!(engine.verify_transaction_basic(&t, &header));
+		engine.verify_transaction_basic(&t, &header)?;
 	}
 	Ok(())
 }
@@ -73,9 +73,9 @@ pub fn verify_block_basic(header: &Header, bytes: &[u8], engine: &Engine) -> Res
 /// Returns a `PreverifiedBlock` structure populated with transactions
 pub fn verify_block_unordered(header: Header, bytes: Bytes, engine: &Engine, check_seal: bool) -> Result<PreverifiedBlock, Error> {
 	if check_seal {
-		try!(engine.verify_block_unordered(&header, Some(&bytes)));
-		for u in try!(UntrustedRlp::new(&bytes).at(2)).iter().map(|rlp| rlp.as_val::<Header>()) {
-			try!(engine.verify_block_unordered(&try!(u), None));
+		engine.verify_block_unordered(&header, Some(&bytes))?;
+		for u in UntrustedRlp::new(&bytes).at(2)?.iter().map(|rlp| rlp.as_val::<Header>()) {
+			engine.verify_block_unordered(&u?, None)?;
 		}
 	}
 	// Verify transactions.
@@ -83,7 +83,7 @@ pub fn verify_block_unordered(header: Header, bytes: Bytes, engine: &Engine, che
 	{
 		let v = BlockView::new(&bytes);
 		for t in v.transactions() {
-			try!(engine.verify_transaction(&t, &header));
+			engine.verify_transaction(&t, &header)?;
 			transactions.push(t);
 		}
 	}
@@ -97,11 +97,11 @@ pub fn verify_block_unordered(header: Header, bytes: Bytes, engine: &Engine, che
 /// Phase 3 verification. Check block information against parent and uncles.
 pub fn verify_block_family(header: &Header, bytes: &[u8], engine: &Engine, bc: &BlockProvider) -> Result<(), Error> {
 	// TODO: verify timestamp
-	let parent = try!(bc.block_header(&header.parent_hash()).ok_or_else(|| Error::from(BlockError::UnknownParent(header.parent_hash().clone()))));
-	try!(verify_parent(&header, &parent));
-	try!(engine.verify_block_family(&header, &parent, Some(bytes)));
+	let parent = bc.block_header(&header.parent_hash()).ok_or_else(|| Error::from(BlockError::UnknownParent(header.parent_hash().clone())))?;
+	verify_parent(&header, &parent)?;
+	engine.verify_block_family(&header, &parent, Some(bytes))?;
 
-	let num_uncles = try!(UntrustedRlp::new(bytes).at(2)).item_count();
+	let num_uncles = UntrustedRlp::new(bytes).at(2)?.item_count();
 	if num_uncles != 0 {
 		if num_uncles > engine.maximum_uncle_count() {
 			return Err(From::from(BlockError::TooManyUncles(OutOfBounds { min: None, max: Some(engine.maximum_uncle_count()), found: num_uncles })));
@@ -124,8 +124,8 @@ pub fn verify_block_family(header: &Header, bytes: &[u8], engine: &Engine, bc: &
 			}
 		}
 
-		for uncle in try!(UntrustedRlp::new(bytes).at(2)).iter().map(|rlp| rlp.as_val::<Header>()) {
-			let uncle = try!(uncle);
+		for uncle in UntrustedRlp::new(bytes).at(2)?.iter().map(|rlp| rlp.as_val::<Header>()) {
+			let uncle = uncle?;
 			if excluded.contains(&uncle.hash()) {
 				return Err(From::from(BlockError::UncleInChain(uncle.hash())))
 			}
@@ -157,7 +157,7 @@ pub fn verify_block_family(header: &Header, bytes: &[u8], engine: &Engine, bc: &
 			// cB.p^7	-------------/
 			// cB.p^8
 			let mut expected_uncle_parent = header.parent_hash().clone();
-			let uncle_parent = try!(bc.block_header(&uncle.parent_hash()).ok_or_else(|| Error::from(BlockError::UnknownUncleParent(uncle.parent_hash().clone()))));
+			let uncle_parent = bc.block_header(&uncle.parent_hash()).ok_or_else(|| Error::from(BlockError::UnknownUncleParent(uncle.parent_hash().clone())))?;
 			for _ in 0..depth {
 				match bc.block_details(&expected_uncle_parent) {
 					Some(details) => {
@@ -170,8 +170,8 @@ pub fn verify_block_family(header: &Header, bytes: &[u8], engine: &Engine, bc: &
 				return Err(From::from(BlockError::UncleParentNotInChain(uncle_parent.hash())));
 			}
 
-			try!(verify_parent(&uncle, &uncle_parent));
-			try!(engine.verify_block_family(&uncle, &uncle_parent, Some(bytes)));
+			verify_parent(&uncle, &uncle_parent)?;
+			engine.verify_block_family(&uncle, &uncle_parent, Some(bytes))?;
 		}
 	}
 	Ok(())
@@ -234,12 +234,12 @@ fn verify_parent(header: &Header, parent: &Header) -> Result<(), Error> {
 /// Verify block data against header: transactions root and uncles hash.
 fn verify_block_integrity(block: &[u8], transactions_root: &H256, uncles_hash: &H256) -> Result<(), Error> {
 	let block = UntrustedRlp::new(block);
-	let tx = try!(block.at(1));
+	let tx = block.at(1)?;
 	let expected_root = &ordered_trie_root(tx.iter().map(|r| r.as_raw().to_vec())); //TODO: get rid of vectors here
 	if expected_root != transactions_root {
 		return Err(From::from(BlockError::InvalidTransactionsRoot(Mismatch { expected: expected_root.clone(), found: transactions_root.clone() })))
 	}
-	let expected_uncles = &try!(block.at(2)).as_raw().sha3();
+	let expected_uncles = &block.at(2)?.as_raw().sha3();
 	if expected_uncles != uncles_hash {
 		return Err(From::from(BlockError::InvalidUnclesHash(Mismatch { expected: expected_uncles.clone(), found: uncles_hash.clone() })))
 	}

ethcrypto/src/lib.rs

@@ -158,7 +158,7 @@ pub mod aes {
 		let mut encryptor = CbcDecryptor::new(AesSafe128Decryptor::new(k), PkcsPadding, iv.to_vec());
 		let len = dest.len();
 		let mut buffer = RefWriteBuffer::new(dest);
-		try!(encryptor.decrypt(&mut RefReadBuffer::new(encrypted), &mut buffer, true));
+		encryptor.decrypt(&mut RefReadBuffer::new(encrypted), &mut buffer, true)?;
 		Ok(len - buffer.remaining())
 	}
 }
@@ -179,7 +179,7 @@ pub mod ecdh {
 			temp
 		};
 
-		let publ = try!(key::PublicKey::from_slice(context, &pdata));
+		let publ = key::PublicKey::from_slice(context, &pdata)?;
 		// no way to create SecretKey from raw byte array.
 		let sec: &key::SecretKey = unsafe { ::std::mem::transmute(secret) };
 		let shared = ecdh::SharedSecret::new_raw(context, &publ, sec);
@@ -206,7 +206,7 @@ pub mod ecies {
 		let r = Random.generate()
 			.expect("context known to have key-generation capabilities; qed");
 
-		let z = try!(ecdh::agree(r.secret(), public));
+		let z = ecdh::agree(r.secret(), public)?;
 		let mut key = [0u8; 32];
 		let mut mkey = [0u8; 32];
 		kdf(&z, &[0u8; 0], &mut key);
@@ -243,7 +243,7 @@ pub mod ecies {
 		let r = Random.generate()
 			.expect("context known to have key-generation capabilities");
 
-		let z = try!(ecdh::agree(r.secret(), public));
+		let z = ecdh::agree(r.secret(), public)?;
 		let mut key = [0u8; 32];
 		let mut mkey = [0u8; 32];
 		kdf(&z, &[0u8; 0], &mut key);
@@ -274,7 +274,7 @@ pub mod ecies {
 
 		let e = &encrypted[1..];
 		let p = Public::from_slice(&e[0..64]);
-		let z = try!(ecdh::agree(secret, &p));
+		let z = ecdh::agree(secret, &p)?;
 		let mut key = [0u8; 32];
 		kdf(&z, &[0u8; 0], &mut key);
 		let ekey = &key[0..16];
@@ -314,7 +314,7 @@ pub mod ecies {
 
 		let e = encrypted;
 		let p = Public::from_slice(&e[0..64]);
-		let z = try!(ecdh::agree(secret, &p));
+		let z = ecdh::agree(secret, &p)?;
 		let mut key = [0u8; 32];
 		kdf(&z, &[0u8; 0], &mut key);
 		let ekey = &key[0..16];

ethkey/src/bin/ethkey.rs

@@ -160,37 +160,37 @@ fn execute<S, I>(command: I) -> Result<String, Error> where I: IntoIterator<Item
 
 	return if args.cmd_info {
 		let display_mode = DisplayMode::new(&args);
-		let secret = try!(args.arg_secret.parse().map_err(|_| EthkeyError::InvalidSecret));
-		let keypair = try!(KeyPair::from_secret(secret));
+		let secret = args.arg_secret.parse().map_err(|_| EthkeyError::InvalidSecret)?;
+		let keypair = KeyPair::from_secret(secret)?;
 		Ok(display(keypair, display_mode))
 	} else if args.cmd_generate {
 		let display_mode = DisplayMode::new(&args);
 		let keypair = if args.cmd_random {
 			Random.generate()
 		} else if args.cmd_prefix {
-			let prefix = try!(args.arg_prefix.from_hex());
-			let iterations = try!(usize::from_str_radix(&args.arg_iterations, 10));
+			let prefix = args.arg_prefix.from_hex()?;
+			let iterations = usize::from_str_radix(&args.arg_iterations, 10)?;
 			Prefix::new(prefix, iterations).generate()
 		} else if args.cmd_brain {
 			Brain::new(args.arg_seed).generate()
 		} else {
 			unreachable!();
 		};
-		Ok(display(try!(keypair), display_mode))
+		Ok(display(keypair?, display_mode))
 	} else if args.cmd_sign {
-		let secret = try!(args.arg_secret.parse().map_err(|_| EthkeyError::InvalidSecret));
-		let message = try!(args.arg_message.parse().map_err(|_| EthkeyError::InvalidMessage));
-		let signature = try!(sign(&secret, &message));
+		let secret = args.arg_secret.parse().map_err(|_| EthkeyError::InvalidSecret)?;
+		let message = args.arg_message.parse().map_err(|_| EthkeyError::InvalidMessage)?;
+		let signature = sign(&secret, &message)?;
 		Ok(format!("{}", signature))
 	} else if args.cmd_verify {
-		let signature = try!(args.arg_signature.parse().map_err(|_| EthkeyError::InvalidSignature));
-		let message = try!(args.arg_message.parse().map_err(|_| EthkeyError::InvalidMessage));
+		let signature = args.arg_signature.parse().map_err(|_| EthkeyError::InvalidSignature)?;
+		let message = args.arg_message.parse().map_err(|_| EthkeyError::InvalidMessage)?;
 		let ok = if args.cmd_public {
-			let public = try!(args.arg_public.parse().map_err(|_| EthkeyError::InvalidPublic));
-			try!(verify_public(&public, &signature, &message))
+			let public = args.arg_public.parse().map_err(|_| EthkeyError::InvalidPublic)?;
+			verify_public(&public, &signature, &message)?
 		} else if args.cmd_address {
-			let address = try!(args.arg_address.parse().map_err(|_| EthkeyError::InvalidAddress));
-			try!(verify_address(&address, &signature, &message))
+			let address = args.arg_address.parse().map_err(|_| EthkeyError::InvalidAddress)?;
+			verify_address(&address, &signature, &message)?
 		} else {
 			unreachable!();
 		};

ethkey/src/keypair.rs

@@ -35,8 +35,8 @@ pub struct KeyPair {
 
 impl fmt::Display for KeyPair {
 	fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-		try!(writeln!(f, "secret:  {}", self.secret.to_hex()));
-		try!(writeln!(f, "public:  {}", self.public.to_hex()));
+		writeln!(f, "secret:  {}", self.secret.to_hex())?;
+		writeln!(f, "public:  {}", self.public.to_hex())?;
 		write!(f, "address: {}", self.address().to_hex())
 	}
 }
@@ -45,8 +45,8 @@ impl KeyPair {
 	/// Create a pair from secret key
 	pub fn from_secret(secret: Secret) -> Result<KeyPair, Error> {
 		let context = &SECP256K1;
-		let s: key::SecretKey = try!(key::SecretKey::from_slice(context, &secret[..]));
-		let pub_key = try!(key::PublicKey::from_secret_key(context, &s));
+		let s: key::SecretKey = key::SecretKey::from_slice(context, &secret[..])?;
+		let pub_key = key::PublicKey::from_secret_key(context, &s)?;
 		let serialized = pub_key.serialize_vec(context, false);
 
 		let mut public = Public::default();

ethkey/src/prefix.rs

@@ -34,7 +34,7 @@ impl Prefix {
 impl Generator for Prefix {
 	fn generate(self) -> Result<KeyPair, Error> {
 		for _ in 0..self.iterations {
-			let keypair = try!(Random.generate());
+			let keypair = Random.generate()?;
 			if keypair.address().starts_with(&self.prefix) {
 				return Ok(keypair)
 			}

ethkey/src/random.rs

@@ -23,8 +23,8 @@ pub struct Random;
 impl Generator for Random {
 	fn generate(self) -> Result<KeyPair, Error> {
 		let context = &SECP256K1;
-		let mut rng = try!(OsRng::new());
-		let (sec, publ) = try!(context.generate_keypair(&mut rng));
+		let mut rng = OsRng::new()?;
+		let (sec, publ) = context.generate_keypair(&mut rng)?;
 
 		Ok(KeyPair::from_keypair(sec, publ))
 	}

ethkey/src/signature.rs

@@ -171,7 +171,7 @@ pub fn sign(secret: &Secret, message: &Message) -> Result<Signature, Error> {
 	let context = &SECP256K1;
 	// no way to create from raw byte array.
 	let sec: &SecretKey = unsafe { mem::transmute(secret) };
-	let s = try!(context.sign_recoverable(&try!(SecpMessage::from_slice(&message[..])), sec));
+	let s = context.sign_recoverable(&SecpMessage::from_slice(&message[..])?, sec)?;
 	let (rec_id, data) = s.serialize_compact(context);
 	let mut data_arr = [0; 65];
 
@@ -183,7 +183,7 @@ pub fn sign(secret: &Secret, message: &Message) -> Result<Signature, Error> {
 
 pub fn verify_public(public: &Public, signature: &Signature, message: &Message) -> Result<bool, Error> {
 	let context = &SECP256K1;
-	let rsig = try!(RecoverableSignature::from_compact(context, &signature[0..64], try!(RecoveryId::from_i32(signature[64] as i32))));
+	let rsig = RecoverableSignature::from_compact(context, &signature[0..64], RecoveryId::from_i32(signature[64] as i32)?)?;
 	let sig = rsig.to_standard(context);
 
 	let pdata: [u8; 65] = {
@@ -192,8 +192,8 @@ pub fn verify_public(public: &Public, signature: &Signature, message: &Message)
 		temp
 	};
 
-	let publ = try!(PublicKey::from_slice(context, &pdata));
-	match context.verify(&try!(SecpMessage::from_slice(&message[..])), &sig, &publ) {
+	let publ = PublicKey::from_slice(context, &pdata)?;
+	match context.verify(&SecpMessage::from_slice(&message[..])?, &sig, &publ) {
 		Ok(_) => Ok(true),
 		Err(SecpError::IncorrectSignature) => Ok(false),
 		Err(x) => Err(Error::from(x))
@@ -201,15 +201,15 @@ pub fn verify_public(public: &Public, signature: &Signature, message: &Message)
 }
 
 pub fn verify_address(address: &Address, signature: &Signature, message: &Message) -> Result<bool, Error> {
-	let public = try!(recover(signature, message));
+	let public = recover(signature, message)?;
 	let recovered_address = public_to_address(&public);
 	Ok(address == &recovered_address)
 }
 
 pub fn recover(signature: &Signature, message: &Message) -> Result<Public, Error> {
 	let context = &SECP256K1;
-	let rsig = try!(RecoverableSignature::from_compact(context, &signature[0..64], try!(RecoveryId::from_i32(signature[64] as i32))));
-	let pubkey = try!(context.recover(&try!(SecpMessage::from_slice(&message[..])), &rsig));
+	let rsig = RecoverableSignature::from_compact(context, &signature[0..64], RecoveryId::from_i32(signature[64] as i32)?)?;
+	let pubkey = context.recover(&SecpMessage::from_slice(&message[..])?, &rsig)?;
 	let serialized = pubkey.serialize_vec(context, false);
 
 	let mut public = Public::default();

ethstore/src/account/safe_account.rs

@@ -113,7 +113,7 @@ impl Crypto {
 
 		let (derived_left_bits, derived_right_bits) = match self.kdf {
 			Kdf::Pbkdf2(ref params) => crypto::derive_key_iterations(password, &params.salt, params.c),
-			Kdf::Scrypt(ref params) => try!(crypto::derive_key_scrypt(password, &params.salt, params.n, params.p, params.r)),
+			Kdf::Scrypt(ref params) => crypto::derive_key_scrypt(password, &params.salt, params.n, params.p, params.r)?,
 		};
 
 		let mac = crypto::derive_mac(&derived_right_bits, &self.ciphertext).keccak256();
@@ -171,22 +171,22 @@ impl SafeAccount {
 	}
 
 	pub fn sign(&self, password: &str, message: &Message) -> Result<Signature, Error> {
-		let secret = try!(self.crypto.secret(password));
+		let secret = self.crypto.secret(password)?;
 		sign(&secret, message).map_err(From::from)
 	}
 
 	pub fn decrypt(&self, password: &str, shared_mac: &[u8], message: &[u8]) -> Result<Vec<u8>, Error> {
-		let secret = try!(self.crypto.secret(password));
+		let secret = self.crypto.secret(password)?;
 		crypto::ecies::decrypt(&secret, shared_mac, message).map_err(From::from)
 	}
 
 	pub fn public(&self, password: &str) -> Result<Public, Error> {
-		let secret = try!(self.crypto.secret(password));
-		Ok(try!(KeyPair::from_secret(secret)).public().clone())
+		let secret = self.crypto.secret(password)?;
+		Ok(KeyPair::from_secret(secret)?.public().clone())
 	}
 
 	pub fn change_password(&self, old_password: &str, new_password: &str, iterations: u32) -> Result<Self, Error> {
-		let secret = try!(self.crypto.secret(old_password));
+		let secret = self.crypto.secret(old_password)?;
 		let result = SafeAccount {
 			id: self.id.clone(),
 			version: self.version.clone(),

ethstore/src/bin/ethstore.rs

@@ -93,11 +93,11 @@ fn main() {
 
 fn key_dir(location: &str) -> Result<Box<KeyDirectory>, Error> {
 	let dir: Box<KeyDirectory> = match location {
-		"parity" => Box::new(try!(ParityDirectory::create(DirectoryType::Main))),
-		"parity-test" => Box::new(try!(ParityDirectory::create(DirectoryType::Testnet))),
-		"geth" => Box::new(try!(GethDirectory::create(DirectoryType::Main))),
-		"geth-test" => Box::new(try!(GethDirectory::create(DirectoryType::Testnet))),
-		path => Box::new(try!(DiskDirectory::create(path))),
+		"parity" => Box::new(ParityDirectory::create(DirectoryType::Main)?),
+		"parity-test" => Box::new(ParityDirectory::create(DirectoryType::Testnet)?),
+		"geth" => Box::new(GethDirectory::create(DirectoryType::Main)?),
+		"geth-test" => Box::new(GethDirectory::create(DirectoryType::Testnet)?),
+		path => Box::new(DiskDirectory::create(path)?),
 	};
 
 	Ok(dir)
@@ -112,9 +112,9 @@ fn format_accounts(accounts: &[Address]) -> String {
 }
 
 fn load_password(path: &str) -> Result<String, Error> {
-	let mut file = try!(fs::File::open(path));
+	let mut file = fs::File::open(path)?;
 	let mut password = String::new();
-	try!(file.read_to_string(&mut password));
+	file.read_to_string(&mut password)?;
 	// drop EOF
 	let _ = password.pop();
 	Ok(password)
@@ -125,48 +125,48 @@ fn execute<S, I>(command: I) -> Result<String, Error> where I: IntoIterator<Item
 		.and_then(|d| d.argv(command).decode())
 		.unwrap_or_else(|e| e.exit());
 
-	let store = try!(EthStore::open(try!(key_dir(&args.flag_dir))));
+	let store = EthStore::open(key_dir(&args.flag_dir)?)?;
 
 	return if args.cmd_insert {
-		let secret = try!(args.arg_secret.parse().map_err(|_| Error::InvalidSecret));
-		let password = try!(load_password(&args.arg_password));
-		let address = try!(store.insert_account(secret, &password));
+		let secret = args.arg_secret.parse().map_err(|_| Error::InvalidSecret)?;
+		let password = load_password(&args.arg_password)?;
+		let address = store.insert_account(secret, &password)?;
 		Ok(format!("0x{:?}", address))
 	} else if args.cmd_change_pwd {
-		let address = try!(args.arg_address.parse().map_err(|_| Error::InvalidAccount));
-		let old_pwd = try!(load_password(&args.arg_old_pwd));
-		let new_pwd = try!(load_password(&args.arg_new_pwd));
+		let address = args.arg_address.parse().map_err(|_| Error::InvalidAccount)?;
+		let old_pwd = load_password(&args.arg_old_pwd)?;
+		let new_pwd = load_password(&args.arg_new_pwd)?;
 		let ok = store.change_password(&address, &old_pwd, &new_pwd).is_ok();
 		Ok(format!("{}", ok))
 	} else if args.cmd_list {
-		let accounts = try!(store.accounts());
+		let accounts = store.accounts()?;
 		Ok(format_accounts(&accounts))
 	} else if args.cmd_import {
-		let src = try!(key_dir(&args.flag_src));
-		let dst = try!(key_dir(&args.flag_dir));
-		let accounts = try!(import_accounts(&*src, &*dst));
+		let src = key_dir(&args.flag_src)?;
+		let dst = key_dir(&args.flag_dir)?;
+		let accounts = import_accounts(&*src, &*dst)?;
 		Ok(format_accounts(&accounts))
 	} else if args.cmd_import_wallet {
-		let wallet = try!(PresaleWallet::open(&args.arg_path));
-		let password = try!(load_password(&args.arg_password));
-		let kp = try!(wallet.decrypt(&password));
-		let address = try!(store.insert_account(kp.secret().clone(), &password));
+		let wallet = PresaleWallet::open(&args.arg_path)?;
+		let password = load_password(&args.arg_password)?;
+		let kp = wallet.decrypt(&password)?;
+		let address = store.insert_account(kp.secret().clone(), &password)?;
 		Ok(format!("0x{:?}", address))
 	} else if args.cmd_remove {
-		let address = try!(args.arg_address.parse().map_err(|_| Error::InvalidAccount));
-		let password = try!(load_password(&args.arg_password));
+		let address = args.arg_address.parse().map_err(|_| Error::InvalidAccount)?;
+		let password = load_password(&args.arg_password)?;
 		let ok = store.remove_account(&address, &password).is_ok();
 		Ok(format!("{}", ok))
 	} else if args.cmd_sign {
-		let address = try!(args.arg_address.parse().map_err(|_| Error::InvalidAccount));
-		let message = try!(args.arg_message.parse().map_err(|_| Error::InvalidMessage));
-		let password = try!(load_password(&args.arg_password));
-		let signature = try!(store.sign(&address, &password, &message));
+		let address = args.arg_address.parse().map_err(|_| Error::InvalidAccount)?;
+		let message = args.arg_message.parse().map_err(|_| Error::InvalidMessage)?;
+		let password = load_password(&args.arg_password)?;
+		let signature = store.sign(&address, &password, &message)?;
 		Ok(format!("0x{:?}", signature))
 	} else if args.cmd_public {
-		let address = try!(args.arg_address.parse().map_err(|_| Error::InvalidAccount));
-		let password = try!(load_password(&args.arg_password));
-		let public = try!(store.public(&address, &password));
+		let address = args.arg_address.parse().map_err(|_| Error::InvalidAccount)?;
+		let password = load_password(&args.arg_password)?;
+		let public = store.public(&address, &password)?;
 		Ok(format!("0x{:?}", public))
 	} else {
 		Ok(format!("{}", USAGE))

ethstore/src/dir/disk.rs

@@ -29,8 +29,8 @@ fn restrict_permissions_to_owner(file_path: &Path) -> Result<(), i32>  {
 	use std::ffi;
 	use libc;
 
-	let cstr = try!(ffi::CString::new(&*file_path.to_string_lossy())
-		.map_err(|_| -1));
+	let cstr = ffi::CString::new(&*file_path.to_string_lossy())
+		.map_err(|_| -1)?;
 	match unsafe { libc::chmod(cstr.as_ptr(), libc::S_IWUSR | libc::S_IRUSR) } {
 		0 => Ok(()),
 		x => Err(x),
@@ -48,7 +48,7 @@ pub struct DiskDirectory {
 
 impl DiskDirectory {
 	pub fn create<P>(path: P) -> Result<Self, Error> where P: AsRef<Path> {
-		try!(fs::create_dir_all(&path));
+		fs::create_dir_all(&path)?;
 		Ok(Self::at(path))
 	}
 
@@ -62,7 +62,7 @@ impl DiskDirectory {
 	fn files(&self) -> Result<HashMap<PathBuf, SafeAccount>, Error> {
 		// it's not done using one iterator cause
 		// there is an issue with rustc and it takes tooo much time to compile
-		let paths = try!(fs::read_dir(&self.path))
+		let paths = fs::read_dir(&self.path)?
 			.flat_map(Result::ok)
 			.filter(|entry| {
 				let metadata = entry.metadata().ok();
@@ -102,7 +102,7 @@ impl DiskDirectory {
 
 impl KeyDirectory for DiskDirectory {
 	fn load(&self) -> Result<Vec<SafeAccount>, Error> {
-		let accounts = try!(self.files())
+		let accounts = self.files()?
 			.into_iter()
 			.map(|(_, account)| account)
 			.collect();
@@ -134,8 +134,8 @@ impl KeyDirectory for DiskDirectory {
 			keyfile_path.push(filename.as_str());
 
 			// save the file
-			let mut file = try!(fs::File::create(&keyfile_path));
-			try!(keyfile.write(&mut file).map_err(|e| Error::Custom(format!("{:?}", e))));
+			let mut file = fs::File::create(&keyfile_path)?;
+			keyfile.write(&mut file).map_err(|e| Error::Custom(format!("{:?}", e)))?;
 
 			if let Err(_) = restrict_permissions_to_owner(keyfile_path.as_path()) {
 				fs::remove_file(keyfile_path).expect("Expected to remove recently created file");
@@ -149,7 +149,7 @@ impl KeyDirectory for DiskDirectory {
 	fn remove(&self, account: &SafeAccount) -> Result<(), Error> {
 		// enumerate all entries in keystore
 		// and find entry with given address
-		let to_remove = try!(self.files())
+		let to_remove = self.files()?
 			.into_iter()
 			.find(|&(_, ref acc)| acc == account);
 

ethstore/src/dir/geth.rs

@@ -66,7 +66,7 @@ pub struct GethDirectory {
 impl GethDirectory {
 	pub fn create(t: DirectoryType) -> Result<Self, Error> {
 		let result = GethDirectory {
-			dir: try!(DiskDirectory::create(geth_keystore(t))),
+			dir: DiskDirectory::create(geth_keystore(t))?,
 		};
 
 		Ok(result)

ethstore/src/dir/parity.rs

@@ -45,7 +45,7 @@ pub struct ParityDirectory {
 impl ParityDirectory {
 	pub fn create(t: DirectoryType) -> Result<Self, Error> {
 		let result = ParityDirectory {
-			dir: try!(DiskDirectory::create(parity_keystore(t))),
+			dir: DiskDirectory::create(parity_keystore(t))?,
 		};
 
 		Ok(result)

ethstore/src/ethstore.rs

@@ -38,12 +38,12 @@ impl EthStore {
 
 	pub fn open_with_iterations(directory: Box<KeyDirectory>, iterations: u32) -> Result<Self, Error> {
 		Ok(EthStore {
-			store: try!(EthMultiStore::open_with_iterations(directory, iterations)),
+			store: EthMultiStore::open_with_iterations(directory, iterations)?,
 		})
 	}
 
 	fn get(&self, address: &Address) -> Result<SafeAccount, Error> {
-		let mut accounts = try!(self.store.get(address)).into_iter();
+		let mut accounts = self.store.get(address)?.into_iter();
 		accounts.next().ok_or(Error::InvalidAccount)
 	}
 }
@@ -66,68 +66,68 @@ impl SimpleSecretStore for EthStore {
 	}
 
 	fn sign(&self, address: &Address, password: &str, message: &Message) -> Result<Signature, Error> {
-		let account = try!(self.get(address));
+		let account = self.get(address)?;
 		account.sign(password, message)
 	}
 
 	fn decrypt(&self, account: &Address, password: &str, shared_mac: &[u8], message: &[u8]) -> Result<Vec<u8>, Error> {
-		let account = try!(self.get(account));
+		let account = self.get(account)?;
 		account.decrypt(password, shared_mac, message)
 	}
 }
 
 impl SecretStore for EthStore {
 	fn import_presale(&self, json: &[u8], password: &str) -> Result<Address, Error> {
-		let json_wallet = try!(json::PresaleWallet::load(json).map_err(|_| Error::InvalidKeyFile("Invalid JSON format".to_owned())));
+		let json_wallet = json::PresaleWallet::load(json).map_err(|_| Error::InvalidKeyFile("Invalid JSON format".to_owned()))?;
 		let wallet = PresaleWallet::from(json_wallet);
-		let keypair = try!(wallet.decrypt(password).map_err(|_| Error::InvalidPassword));
+		let keypair = wallet.decrypt(password).map_err(|_| Error::InvalidPassword)?;
 		self.insert_account(keypair.secret().clone(), password)
 	}
 
 	fn import_wallet(&self, json: &[u8], password: &str) -> Result<Address, Error> {
-		let json_keyfile = try!(json::KeyFile::load(json).map_err(|_| Error::InvalidKeyFile("Invalid JSON format".to_owned())));
+		let json_keyfile = json::KeyFile::load(json).map_err(|_| Error::InvalidKeyFile("Invalid JSON format".to_owned()))?;
 		let mut safe_account = SafeAccount::from_file(json_keyfile, None);
-		let secret = try!(safe_account.crypto.secret(password).map_err(|_| Error::InvalidPassword));
-		safe_account.address = try!(KeyPair::from_secret(secret)).address();
+		let secret = safe_account.crypto.secret(password).map_err(|_| Error::InvalidPassword)?;
+		safe_account.address = KeyPair::from_secret(secret)?.address();
 		let address = safe_account.address.clone();
-		try!(self.store.import(safe_account));
+		self.store.import(safe_account)?;
 		Ok(address)
 	}
 
 	fn test_password(&self, address: &Address, password: &str) -> Result<bool, Error> {
-		let account = try!(self.get(address));
+		let account = self.get(address)?;
 		Ok(account.check_password(password))
 	}
 
 	fn copy_account(&self, new_store: &SimpleSecretStore, address: &Address, password: &str, new_password: &str) -> Result<(), Error> {
-		let account = try!(self.get(address));
-		let secret = try!(account.crypto.secret(password));
-		try!(new_store.insert_account(secret, new_password));
+		let account = self.get(address)?;
+		let secret = account.crypto.secret(password)?;
+		new_store.insert_account(secret, new_password)?;
 		Ok(())
 	}
 
 	fn public(&self, account: &Address, password: &str) -> Result<Public, Error> {
-		let account = try!(self.get(account));
+		let account = self.get(account)?;
 		account.public(password)
 	}
 
 	fn uuid(&self, address: &Address) -> Result<Uuid, Error> {
-		let account = try!(self.get(address));
+		let account = self.get(address)?;
 		Ok(account.id.into())
 	}
 
 	fn name(&self, address: &Address) -> Result<String, Error> {
-		let account = try!(self.get(address));
+		let account = self.get(address)?;
 		Ok(account.name.clone())
 	}
 
 	fn meta(&self, address: &Address) -> Result<String, Error> {
-		let account = try!(self.get(address));
+		let account = self.get(address)?;
 		Ok(account.meta.clone())
 	}
 
 	fn set_name(&self, address: &Address, name: String) -> Result<(), Error> {
-		let old = try!(self.get(address));
+		let old = self.get(address)?;
 		let mut account = old.clone();
 		account.name = name;
 
@@ -136,7 +136,7 @@ impl SecretStore for EthStore {
 	}
 
 	fn set_meta(&self, address: &Address, meta: String) -> Result<(), Error> {
-		let old = try!(self.get(address));
+		let old = self.get(address)?;
 		let mut account = old.clone();
 		account.meta = meta;
 
@@ -176,13 +176,13 @@ impl EthMultiStore {
 			iterations: iterations,
 			cache: Default::default(),
 		};
-		try!(store.reload_accounts());
+		store.reload_accounts()?;
 		Ok(store)
 	}
 
 	fn reload_accounts(&self) -> Result<(), Error> {
 		let mut cache = self.cache.write();
-		let accounts = try!(self.dir.load());
+		let accounts = self.dir.load()?;
 
 		let mut new_accounts = BTreeMap::new();
 		for account in accounts {
@@ -203,9 +203,9 @@ impl EthMultiStore {
 			}
 		}
 
-		try!(self.reload_accounts());
+		self.reload_accounts()?;
 		let cache = self.cache.read();
-		let accounts = try!(cache.get(address).cloned().ok_or(Error::InvalidAccount));
+		let accounts = cache.get(address).cloned().ok_or(Error::InvalidAccount)?;
 		if accounts.is_empty() {
 			Err(Error::InvalidAccount)
 		} else {
@@ -215,7 +215,7 @@ impl EthMultiStore {
 
 	fn import(&self, account: SafeAccount) -> Result<(), Error> {
 		// save to file
-		let account = try!(self.dir.insert(account));
+		let account = self.dir.insert(account)?;
 
 		// update cache
 		let mut cache = self.cache.write();
@@ -226,7 +226,7 @@ impl EthMultiStore {
 
 	fn update(&self, old: SafeAccount, new: SafeAccount) -> Result<(), Error> {
 		// save to file
-		let account = try!(self.dir.update(new));
+		let account = self.dir.update(new)?;
 
 		// update cache
 		let mut cache = self.cache.write();
@@ -243,21 +243,21 @@ impl EthMultiStore {
 
 impl SimpleSecretStore for EthMultiStore {
 	fn insert_account(&self, secret: Secret, password: &str) -> Result<Address, Error> {
-		let keypair = try!(KeyPair::from_secret(secret).map_err(|_| Error::CreationFailed));
+		let keypair = KeyPair::from_secret(secret).map_err(|_| Error::CreationFailed)?;
 		let id: [u8; 16] = Random::random();
 		let account = SafeAccount::create(&keypair, id, password, self.iterations, "".to_owned(), "{}".to_owned());
 		let address = account.address.clone();
-		try!(self.import(account));
+		self.import(account)?;
 		Ok(address)
 	}
 
 	fn accounts(&self) -> Result<Vec<Address>, Error> {
-		try!(self.reload_accounts());
+		self.reload_accounts()?;
 		Ok(self.cache.read().keys().cloned().collect())
 	}
 
 	fn remove_account(&self, address: &Address, password: &str) -> Result<(), Error> {
-		let accounts = try!(self.get(address));
+		let accounts = self.get(address)?;
 
 		for account in accounts {
 			// Skip if password is invalid
@@ -266,7 +266,7 @@ impl SimpleSecretStore for EthMultiStore {
 			}
 
 			// Remove from dir
-			try!(self.dir.remove(&account));
+			self.dir.remove(&account)?;
 
 			// Remove from cache
 			let mut cache = self.cache.write();
@@ -288,17 +288,17 @@ impl SimpleSecretStore for EthMultiStore {
 	}
 
 	fn change_password(&self, address: &Address, old_password: &str, new_password: &str) -> Result<(), Error> {
-		let accounts = try!(self.get(address));
+		let accounts = self.get(address)?;
 		for account in accounts {
 			// Change password
-			let new_account = try!(account.change_password(old_password, new_password, self.iterations));
-			try!(self.update(account, new_account));
+			let new_account = account.change_password(old_password, new_password, self.iterations)?;
+			self.update(account, new_account)?;
 		}
 		Ok(())
 	}
 
 	fn sign(&self, address: &Address, password: &str, message: &Message) -> Result<Signature, Error> {
-		let accounts = try!(self.get(address));
+		let accounts = self.get(address)?;
 		for account in accounts {
 			if account.check_password(password) {
 				return account.sign(password, message);
@@ -309,7 +309,7 @@ impl SimpleSecretStore for EthMultiStore {
 	}
 
 	fn decrypt(&self, account: &Address, password: &str, shared_mac: &[u8], message: &[u8]) -> Result<Vec<u8>, Error> {
-		let accounts = try!(self.get(account));
+		let accounts = self.get(account)?;
 		for account in accounts {
 			if account.check_password(password) {
 				return account.decrypt(password, shared_mac, message);

ethstore/src/import.rs

@@ -20,14 +20,14 @@ use dir::{GethDirectory, KeyDirectory, DirectoryType};
 use Error;
 
 pub fn import_accounts(src: &KeyDirectory, dst: &KeyDirectory) -> Result<Vec<Address>, Error> {
-	let accounts = try!(src.load());
-	let existing_accounts = try!(dst.load()).into_iter().map(|a| a.address).collect::<HashSet<_>>();
+	let accounts = src.load()?;
+	let existing_accounts = dst.load()?.into_iter().map(|a| a.address).collect::<HashSet<_>>();
 
 	accounts.into_iter()
 		.filter(|a| !existing_accounts.contains(&a.address))
 		.map(|a| {
 			let address = a.address.clone();
-			try!(dst.insert(a));
+			dst.insert(a)?;
 			Ok(address)
 		}).collect()
 }
@@ -55,15 +55,15 @@ pub fn import_geth_accounts(dst: &KeyDirectory, desired: HashSet<Address>, testn
 	};
 
 	let src = GethDirectory::open(t);
-	let accounts = try!(src.load());
-	let existing_accounts = try!(dst.load()).into_iter().map(|a| a.address).collect::<HashSet<_>>();
+	let accounts = src.load()?;
+	let existing_accounts = dst.load()?.into_iter().map(|a| a.address).collect::<HashSet<_>>();
 
 	accounts.into_iter()
 		.filter(|a| !existing_accounts.contains(&a.address))
 		.filter(|a| desired.contains(&a.address))
 		.map(|a| {
 			let address = a.address.clone();
-			try!(dst.insert(a));
+			dst.insert(a)?;
 			Ok(address)
 		}).collect()
 }

ethstore/src/json/bytes.rs

@@ -17,8 +17,8 @@ impl Deserialize for Bytes {
 	fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
 		where D: Deserializer
 	{
-		let s = try!(String::deserialize(deserializer));
-		let data = try!(s.from_hex().map_err(|e| Error::custom(format!("Invalid hex value {}", e))));
+		let s = String::deserialize(deserializer)?;
+		let data = s.from_hex().map_err(|e| Error::custom(format!("Invalid hex value {}", e)))?;
 		Ok(Bytes(data))
 	}
 }

ethstore/src/json/crypto.rs

@@ -90,13 +90,13 @@ impl Visitor for CryptoVisitor {
 		let mut mac = None;
 
 		loop {
-			match try!(visitor.visit_key()) {
-				Some(CryptoField::Cipher) => { cipher = Some(try!(visitor.visit_value())); }
-				Some(CryptoField::CipherParams) => { cipherparams = Some(try!(visitor.visit_value())); }
-				Some(CryptoField::CipherText) => { ciphertext = Some(try!(visitor.visit_value())); }
-				Some(CryptoField::Kdf) => { kdf = Some(try!(visitor.visit_value())); }
-				Some(CryptoField::KdfParams) => { kdfparams = Some(try!(visitor.visit_value())); }
-				Some(CryptoField::Mac) => { mac = Some(try!(visitor.visit_value())); }
+			match visitor.visit_key()? {
+				Some(CryptoField::Cipher) => { cipher = Some(visitor.visit_value()?); }
+				Some(CryptoField::CipherParams) => { cipherparams = Some(visitor.visit_value()?); }
+				Some(CryptoField::CipherText) => { ciphertext = Some(visitor.visit_value()?); }
+				Some(CryptoField::Kdf) => { kdf = Some(visitor.visit_value()?); }
+				Some(CryptoField::KdfParams) => { kdfparams = Some(visitor.visit_value()?); }
+				Some(CryptoField::Mac) => { mac = Some(visitor.visit_value()?); }
 				None => { break; }
 			}
 		}
@@ -109,7 +109,7 @@ impl Visitor for CryptoVisitor {
 
 		let ciphertext = match ciphertext {
 			Some(ciphertext) => ciphertext,
-			None => try!(visitor.missing_field("ciphertext")),
+			None => visitor.missing_field("ciphertext")?,
 		};
 
 		let kdf = match (kdf, kdfparams) {
@@ -122,10 +122,10 @@ impl Visitor for CryptoVisitor {
 
 		let mac = match mac {
 			Some(mac) => mac,
-			None => try!(visitor.missing_field("mac")),
+			None => visitor.missing_field("mac")?,
 		};
 
-		try!(visitor.end());
+		visitor.end()?;
 
 		let result = Crypto {
 			cipher: cipher,
@@ -142,26 +142,26 @@ impl Serialize for Crypto {
 	fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
 		where S: Serializer
 	{
-		let mut state = try!(serializer.serialize_struct("Crypto", 6));
+		let mut state = serializer.serialize_struct("Crypto", 6)?;
 		match self.cipher {
 			Cipher::Aes128Ctr(ref params) => {
-				try!(serializer.serialize_struct_elt(&mut state, "cipher", &CipherSer::Aes128Ctr));
-				try!(serializer.serialize_struct_elt(&mut state, "cipherparams", params));
+				serializer.serialize_struct_elt(&mut state, "cipher", &CipherSer::Aes128Ctr)?;
+				serializer.serialize_struct_elt(&mut state, "cipherparams", params)?;
 			},
 		}
-		try!(serializer.serialize_struct_elt(&mut state, "ciphertext", &self.ciphertext));
+		serializer.serialize_struct_elt(&mut state, "ciphertext", &self.ciphertext)?;
 		match self.kdf {
 			Kdf::Pbkdf2(ref params) => {
-				try!(serializer.serialize_struct_elt(&mut state, "kdf", &KdfSer::Pbkdf2));
-				try!(serializer.serialize_struct_elt(&mut state, "kdfparams", params));
+				serializer.serialize_struct_elt(&mut state, "kdf", &KdfSer::Pbkdf2)?;
+				serializer.serialize_struct_elt(&mut state, "kdfparams", params)?;
 			},
 			Kdf::Scrypt(ref params) => {
-				try!(serializer.serialize_struct_elt(&mut state, "kdf", &KdfSer::Scrypt));
-				try!(serializer.serialize_struct_elt(&mut state, "kdfparams", params));
+				serializer.serialize_struct_elt(&mut state, "kdf", &KdfSer::Scrypt)?;
+				serializer.serialize_struct_elt(&mut state, "kdfparams", params)?;
 			},
 		}
 
-		try!(serializer.serialize_struct_elt(&mut state, "mac", &self.mac));
+		serializer.serialize_struct_elt(&mut state, "mac", &self.mac)?;
 		serializer.serialize_struct_end(state)
 	}
 }

ethstore/src/json/id.rs

@@ -62,7 +62,7 @@ impl fmt::Display for Uuid {
 }
 
 fn copy_into(from: &str, into: &mut [u8]) -> Result<(), Error> {
-	let from = try!(from.from_hex().map_err(|_| Error::InvalidUuid));
+	let from = from.from_hex().map_err(|_| Error::InvalidUuid)?;
 
 	if from.len() != into.len() {
 		return Err(Error::InvalidUuid);
@@ -84,11 +84,11 @@ impl str::FromStr for Uuid {
 
 		let mut uuid = [0u8; 16];
 
-		try!(copy_into(parts[0], &mut uuid[0..4]));
-		try!(copy_into(parts[1], &mut uuid[4..6]));
-		try!(copy_into(parts[2], &mut uuid[6..8]));
-		try!(copy_into(parts[3], &mut uuid[8..10]));
-		try!(copy_into(parts[4], &mut uuid[10..16]));
+		copy_into(parts[0], &mut uuid[0..4])?;
+		copy_into(parts[1], &mut uuid[4..6])?;
+		copy_into(parts[2], &mut uuid[6..8])?;
+		copy_into(parts[3], &mut uuid[8..10])?;
+		copy_into(parts[4], &mut uuid[10..16])?;
 
 		Ok(Uuid(uuid))
 	}

ethstore/src/json/kdf.rs

@@ -134,7 +134,7 @@ impl Serialize for KdfSerParams {
 impl Deserialize for KdfSerParams {
 	fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
 	where D: Deserializer {
-		let v = try!(Value::deserialize(deserializer));
+		let v = Value::deserialize(deserializer)?;
 
 		Deserialize::deserialize(&mut value::Deserializer::new(v.clone())).map(KdfSerParams::Pbkdf2)
 			.or_else(|_| Deserialize::deserialize(&mut value::Deserializer::new(v)).map(KdfSerParams::Scrypt))

ethstore/src/json/key_file.rs

@@ -93,11 +93,11 @@ impl Visitor for KeyFileVisitor {
 		let mut meta = None;
 
 		loop {
-			match try!(visitor.visit_key()) {
-				Some(KeyFileField::Id) => { id = Some(try!(visitor.visit_value())); }
-				Some(KeyFileField::Version) => { version = Some(try!(visitor.visit_value())); }
-				Some(KeyFileField::Crypto) => { crypto = Some(try!(visitor.visit_value())); }
-				Some(KeyFileField::Address) => { address = Some(try!(visitor.visit_value())); }
+			match visitor.visit_key()? {
+				Some(KeyFileField::Id) => { id = Some(visitor.visit_value()?); }
+				Some(KeyFileField::Version) => { version = Some(visitor.visit_value()?); }
+				Some(KeyFileField::Crypto) => { crypto = Some(visitor.visit_value()?); }
+				Some(KeyFileField::Address) => { address = Some(visitor.visit_value()?); }
 				Some(KeyFileField::Name) => { name = visitor.visit_value().ok(); }	// ignore anyhing that is not a string to be permissive.
 				Some(KeyFileField::Meta) => { meta = visitor.visit_value().ok(); }	// ignore anyhing that is not a string to be permissive.
 				None => { break; }
@@ -106,25 +106,25 @@ impl Visitor for KeyFileVisitor {
 
 		let id = match id {
 			Some(id) => id,
-			None => try!(visitor.missing_field("id")),
+			None => visitor.missing_field("id")?,
 		};
 
 		let version = match version {
 			Some(version) => version,
-			None => try!(visitor.missing_field("version")),
+			None => visitor.missing_field("version")?,
 		};
 
 		let crypto = match crypto {
 			Some(crypto) => crypto,
-			None => try!(visitor.missing_field("crypto")),
+			None => visitor.missing_field("crypto")?,
 		};
 
 		let address = match address {
 			Some(address) => address,
-			None => try!(visitor.missing_field("address")),
+			None => visitor.missing_field("address")?,
 		};
 
-		try!(visitor.end());
+		visitor.end()?;
 
 		let result = KeyFile {
 			id: id,

ethstore/src/presale.rs

@@ -32,9 +32,9 @@ impl From<json::PresaleWallet> for PresaleWallet {
 
 impl PresaleWallet {
 	pub fn open<P>(path: P) -> Result<Self, Error> where P: AsRef<Path> {
-		let file = try!(fs::File::open(path));
-		let presale = try!(json::PresaleWallet::load(file)
-			.map_err(|e| Error::InvalidKeyFile(format!("{}", e))));
+		let file = fs::File::open(path)?;
+		let presale = json::PresaleWallet::load(file)
+			.map_err(|e| Error::InvalidKeyFile(format!("{}", e)))?;
 		Ok(PresaleWallet::from(presale))
 	}
 
@@ -44,7 +44,7 @@ impl PresaleWallet {
 		pbkdf2(&mut h_mac, password.as_bytes(), 2000, &mut derived_key);
 
 		let mut key = vec![0; self.ciphertext.len()];
-		let len = try!(crypto::aes::decrypt_cbc(&derived_key, &self.iv, &self.ciphertext, &mut key).map_err(|_| Error::InvalidPassword));
+		let len = crypto::aes::decrypt_cbc(&derived_key, &self.iv, &self.ciphertext, &mut key).map_err(|_| Error::InvalidPassword)?;
 		let unpadded = &key[..len];
 
 		let secret = Secret::from(unpadded.keccak256());

ethstore/tests/util/transient_dir.rs

@@ -36,7 +36,7 @@ impl TransientDir {
 	pub fn create() -> Result<Self, Error> {
 		let path = random_dir();
 		let result = TransientDir {
-			dir: try!(DiskDirectory::create(&path)),
+			dir: DiskDirectory::create(&path)?,
 			path: path,
 		};
 

evmbin/src/main.rs

@@ -104,9 +104,9 @@ pub struct Success {
 }
 impl fmt::Display for Success {
 	fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-		try!(writeln!(f, "Gas used: {:?}", self.gas_used));
-		try!(writeln!(f, "Output: {:?}", self.output));
-		try!(writeln!(f, "Time: {}.{:.9}s", self.time.as_secs(), self.time.subsec_nanos()));
+		writeln!(f, "Gas used: {:?}", self.gas_used)?;
+		writeln!(f, "Output: {:?}", self.output)?;
+		writeln!(f, "Time: {}.{:.9}s", self.time.as_secs(), self.time.subsec_nanos())?;
 		Ok(())
 	}
 }
@@ -120,8 +120,8 @@ pub struct Failure {
 }
 impl fmt::Display for Failure {
 	fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-		try!(writeln!(f, "Error: {:?}", self.error));
-		try!(writeln!(f, "Time: {}.{:.9}s", self.time.as_secs(), self.time.subsec_nanos()));
+		writeln!(f, "Error: {:?}", self.error)?;
+		writeln!(f, "Time: {}.{:.9}s", self.time.as_secs(), self.time.subsec_nanos())?;
 		Ok(())
 	}
 }

hash-fetch/src/client.rs

@@ -114,16 +114,16 @@ impl<F: Fetch + 'static> HashFetch for Client<F> {
 			Ok(url) => {
 				let future = self.fetch.fetch(&url).then(move |result| {
 					fn validate_hash(path: PathBuf, hash: H256, result: Result<Response, FetchError>) -> Result<PathBuf, Error> {
-						let response = try!(result);
+						let response = result?;
 						// Read the response
 						let mut reader = io::BufReader::new(response);
-						let mut writer = io::BufWriter::new(try!(fs::File::create(&path)));
-						try!(io::copy(&mut reader, &mut writer));
-						try!(writer.flush());
+						let mut writer = io::BufWriter::new(fs::File::create(&path)?);
+						io::copy(&mut reader, &mut writer)?;
+						writer.flush()?;
 
 						// And validate the hash
-						let mut file_reader = io::BufReader::new(try!(fs::File::open(&path)));
-						let content_hash = try!(sha3(&mut file_reader));
+						let mut file_reader = io::BufReader::new(fs::File::open(&path)?);
+						let content_hash = sha3(&mut file_reader)?;
 						if content_hash != hash {
 							Err(Error::HashMismatch{ got: content_hash, expected: hash })
 						} else {

hash-fetch/src/urlhint.rs

@@ -119,12 +119,12 @@ impl URLHintContract {
 
 	fn urlhint_address(&self) -> Option<Address> {
 		let res = || {
-			let get_address = try!(self.registrar.function("getAddress".into()).map_err(as_string));
-			let params = try!(get_address.encode_call(
+			let get_address = self.registrar.function("getAddress".into()).map_err(as_string)?;
+			let params = get_address.encode_call(
 					vec![Token::FixedBytes((*"githubhint".sha3()).to_vec()), Token::String("A".into())]
-			).map_err(as_string));
-			let output = try!(self.client.call(try!(self.client.registrar()), params));
-			let result = try!(get_address.decode_output(output).map_err(as_string));
+			).map_err(as_string)?;
+			let output = self.client.call(self.client.registrar()?, params)?;
+			let result = get_address.decode_output(output).map_err(as_string)?;
 
 			match result.get(0) {
 				Some(&Token::Address(address)) if address != *Address::default() => Ok(address.into()),

ipc/codegen/src/lib.rs

@@ -162,7 +162,7 @@ fn cleanup(src_path: &str, attr: AttributeKind) -> Result<(), Error> {
 	use std::path::{Path, PathBuf};
 
 	let out_dir = env::var_os("OUT_DIR").unwrap();
-	let file_name = try!(PathBuf::from(src_path).file_name().ok_or(Error::InvalidFileName).map(|val| val.to_str().unwrap().to_owned()));
+	let file_name = PathBuf::from(src_path).file_name().ok_or(Error::InvalidFileName).map(|val| val.to_str().unwrap().to_owned())?;
 	let mut registry = syntex::Registry::new();
 
 	match attr {
@@ -183,7 +183,7 @@ pub fn derive_ipc(src_path: &str) -> Result<(), Error> {
 	use std::path::{Path, PathBuf};
 
 	let out_dir = env::var_os("OUT_DIR").unwrap();
-	let file_name = try!(PathBuf::from(src_path).file_name().ok_or(Error::InvalidFileName).map(|val| val.to_str().unwrap().to_owned()));
+	let file_name = PathBuf::from(src_path).file_name().ok_or(Error::InvalidFileName).map(|val| val.to_str().unwrap().to_owned())?;
 
 	let final_path = Path::new(&out_dir).join(&file_name);
 
@@ -217,7 +217,7 @@ pub fn derive_binary(src_path: &str) -> Result<(), Error> {
 	use std::path::{Path, PathBuf};
 
 	let out_dir = env::var_os("OUT_DIR").unwrap();
-	let file_name = try!(PathBuf::from(src_path).file_name().ok_or(Error::InvalidFileName).map(|val| val.to_str().unwrap().to_owned()));
+	let file_name = PathBuf::from(src_path).file_name().ok_or(Error::InvalidFileName).map(|val| val.to_str().unwrap().to_owned())?;
 	let final_path = Path::new(&out_dir).join(&file_name);
 
 	let mut registry = syntex::Registry::new();

ipc/codegen/src/serialization.rs

@@ -388,8 +388,7 @@ fn binary_expr_enum(
 	span: Span,
 	enum_def: &ast::EnumDef,
 ) -> Result<BinaryExpressions, Error> {
-	let arms: Vec<_> = try!(
-		enum_def.variants.iter()
+	let arms: Vec<_> = try!(enum_def.variants.iter()
 			.enumerate()
 			.map(|(variant_index, variant)| {
 				binary_expr_variant(
@@ -403,8 +402,7 @@ fn binary_expr_enum(
 					variant_index,
 				)
 			})
-			.collect()
-	);
+			.collect());
 
 	let (size_arms, write_arms, mut read_arms) = (
 		arms.iter().map(|x| x.size.clone()).collect::<Vec<ast::Arm>>(),

ipc/nano/src/lib.rs

@@ -65,17 +65,17 @@ impl<S> Deref for GuardedSocket<S> where S: WithSocket<Socket> {
 /// creates socket and connects endpoint to it
 /// for duplex (paired) connections with the service
 pub fn init_duplex_client<S>(socket_addr: &str) -> Result<GuardedSocket<S>, SocketError> where S: WithSocket<Socket> {
-	let mut socket = try!(Socket::new(Protocol::Pair).map_err(|e| {
+	let mut socket = Socket::new(Protocol::Pair).map_err(|e| {
 		warn!(target: "ipc", "Failed to create ipc socket: {:?}", e);
 		SocketError::DuplexLink
-	}));
+	})?;
 
 	socket.set_receive_timeout(DEFAULT_CONNECTION_TIMEOUT).unwrap();
 
-	let endpoint = try!(socket.connect(socket_addr).map_err(|e| {
+	let endpoint = socket.connect(socket_addr).map_err(|e| {
 		warn!(target: "ipc", "Failed to bind socket to address '{}': {:?}", socket_addr, e);
 		SocketError::DuplexLink
-	}));
+	})?;
 
 	Ok(GuardedSocket {
 		client: Arc::new(S::init(socket)),
@@ -87,19 +87,19 @@ pub fn init_duplex_client<S>(socket_addr: &str) -> Result<GuardedSocket<S>, Sock
 /// creates socket and connects endpoint to it
 /// for request-reply connections to the service
 pub fn client<S>(socket_addr: &str, receive_timeout: Option<isize>) -> Result<GuardedSocket<S>, SocketError> where S: WithSocket<Socket> {
-	let mut socket = try!(Socket::new(Protocol::Req).map_err(|e| {
+	let mut socket = Socket::new(Protocol::Req).map_err(|e| {
 		warn!(target: "ipc", "Failed to create ipc socket: {:?}", e);
 		SocketError::RequestLink
-	}));
+	})?;
 
 	if let Some(timeout) = receive_timeout {
 		socket.set_receive_timeout(timeout).unwrap();
 	}
 
-	let endpoint = try!(socket.connect(socket_addr).map_err(|e| {
+	let endpoint = socket.connect(socket_addr).map_err(|e| {
 		warn!(target: "ipc", "Failed to bind socket to address '{}': {:?}", socket_addr, e);
 		SocketError::RequestLink
-	}));
+	})?;
 
 	trace!(target: "ipc", "Created client for {}", socket_addr);
 	Ok(GuardedSocket {
@@ -210,15 +210,15 @@ impl<S: ?Sized> Worker<S> where S: IpcInterface {
 	/// Add exclusive socket for paired client
 	/// Only one connection over this address is allowed
 	pub fn add_duplex(&mut self, addr: &str) -> Result<(), SocketError>  {
-		let mut socket = try!(Socket::new(Protocol::Pair).map_err(|e| {
+		let mut socket = Socket::new(Protocol::Pair).map_err(|e| {
 			warn!(target: "ipc", "Failed to create ipc socket: {:?}", e);
 			SocketError::DuplexLink
-		}));
+		})?;
 
-		let endpoint = try!(socket.bind(addr).map_err(|e| {
+		let endpoint = socket.bind(addr).map_err(|e| {
 			warn!(target: "ipc", "Failed to bind socket to address '{}': {:?}", addr, e);
 			SocketError::DuplexLink
-		}));
+		})?;
 
 		self.sockets.push((socket, endpoint));
 
@@ -232,16 +232,16 @@ impl<S: ?Sized> Worker<S> where S: IpcInterface {
 	/// Add generic socket for request-reply style communications
 	/// with multiple clients
 	pub fn add_reqrep(&mut self, addr: &str) -> Result<(), SocketError>  {
-		let mut socket = try!(Socket::new(Protocol::Rep).map_err(|e| {
+		let mut socket = Socket::new(Protocol::Rep).map_err(|e| {
 			warn!(target: "ipc", "Failed to create ipc socket: {:?}", e);
 			SocketError::DuplexLink
-		}));
+		})?;
 
 
-		let endpoint = try!(socket.bind(addr).map_err(|e| {
+		let endpoint = socket.bind(addr).map_err(|e| {
 			warn!(target: "ipc", "Failed to bind socket to address '{}': {:?}", addr, e);
 			SocketError::DuplexLink
-		}));
+		})?;
 
 		self.sockets.push((socket, endpoint));
 

ipc/rpc/src/binary.rs

@@ -121,7 +121,7 @@ impl<T> BinaryConvertable for Option<T> where T: BinaryConvertable {
 
 	fn from_bytes(buffer: &[u8], length_stack: &mut VecDeque<usize>) -> Result<Self, BinaryConvertError> {
 		if buffer.len() == 0 { return Self::from_empty_bytes(); }
-		Ok(Some(try!(T::from_bytes(buffer, length_stack))))
+		Ok(Some(T::from_bytes(buffer, length_stack)?))
 	}
 
 	fn from_empty_bytes() -> Result<Self, BinaryConvertError> {
@@ -144,12 +144,12 @@ impl<E: BinaryConvertable> BinaryConvertable for Result<(), E> {
 	fn to_bytes(&self, buffer: &mut [u8], length_stack: &mut VecDeque<usize>) -> Result<(), BinaryConvertError> {
 		match *self {
 			Ok(_) => Err(BinaryConvertError::empty()),
-			Err(ref e) => Ok(try!(e.to_bytes(buffer, length_stack))),
+			Err(ref e) => Ok(e.to_bytes(buffer, length_stack)?),
 		}
 	}
 
 	fn from_bytes(buffer: &[u8], length_stack: &mut VecDeque<usize>) -> Result<Self, BinaryConvertError> {
-		Ok(Err(try!(E::from_bytes(&buffer, length_stack))))
+		Ok(Err(E::from_bytes(&buffer, length_stack)?))
 	}
 
 	fn from_empty_bytes() -> Result<Self, BinaryConvertError> {
@@ -172,13 +172,13 @@ impl<R: BinaryConvertable> BinaryConvertable for Result<R, ()> {
 
 	fn to_bytes(&self, buffer: &mut [u8], length_stack: &mut VecDeque<usize>) -> Result<(), BinaryConvertError> {
 		match *self {
-			Ok(ref r) => Ok(try!(r.to_bytes(buffer, length_stack))),
+			Ok(ref r) => Ok(r.to_bytes(buffer, length_stack)?),
 			Err(_) => Err(BinaryConvertError::empty()),
 		}
 	}
 
 	fn from_bytes(buffer: &[u8], length_stack: &mut VecDeque<usize>) -> Result<Self, BinaryConvertError> {
-		Ok(Ok(try!(R::from_bytes(&buffer, length_stack))))
+		Ok(Ok(R::from_bytes(&buffer, length_stack)?))
 	}
 
 	fn from_empty_bytes() -> Result<Self, BinaryConvertError> {
@@ -203,14 +203,14 @@ impl<R: BinaryConvertable, E: BinaryConvertable> BinaryConvertable for Result<R,
 			Ok(ref r) => {
 				buffer[0] = 0;
 				if r.size() > 0 {
-					Ok(try!(r.to_bytes(&mut buffer[1..], length_stack)))
+					Ok(r.to_bytes(&mut buffer[1..], length_stack)?)
 				}
 				else { Ok(()) }
 			},
 			Err(ref e) => {
 				buffer[0] = 1;
 				if e.size() > 0 {
-					Ok(try!(e.to_bytes(&mut buffer[1..], length_stack)))
+					Ok(e.to_bytes(&mut buffer[1..], length_stack)?)
 				}
 				else { Ok(()) }
 			},
@@ -221,11 +221,11 @@ impl<R: BinaryConvertable, E: BinaryConvertable> BinaryConvertable for Result<R,
 		match buffer[0] {
 			0 => {
 				match buffer.len() {
-					1 => Ok(Ok(try!(R::from_empty_bytes()))),
-					_ => Ok(Ok(try!(R::from_bytes(&buffer[1..], length_stack)))),
+					1 => Ok(Ok(R::from_empty_bytes()?)),
+					_ => Ok(Ok(R::from_bytes(&buffer[1..], length_stack)?)),
 				}
 			}
-			1 => Ok(Err(try!(E::from_bytes(&buffer[1..], length_stack)))),
+			1 => Ok(Err(E::from_bytes(&buffer[1..], length_stack)?)),
 			_ => Err(BinaryConvertError::variant(buffer[0]))
 		}
 	}
@@ -260,13 +260,13 @@ impl<K, V> BinaryConvertable for BTreeMap<K, V> where K : BinaryConvertable + Or
 
 			if key_size > 0 {
 				let item_end = offset + key_size;
-				try!(key.to_bytes(&mut buffer[offset..item_end], length_stack));
+				key.to_bytes(&mut buffer[offset..item_end], length_stack)?;
 				offset = item_end;
 			}
 
 			if val_size > 0 {
 				let item_end = offset + key_size;
-				try!(val.to_bytes(&mut buffer[offset..item_end], length_stack));
+				val.to_bytes(&mut buffer[offset..item_end], length_stack)?;
 				offset = item_end;
 			}
 		}
@@ -282,29 +282,29 @@ impl<K, V> BinaryConvertable for BTreeMap<K, V> where K : BinaryConvertable + Or
 		loop {
 			let key_size = match K::len_params() {
 				0 => mem::size_of::<K>(),
-				_ => try!(length_stack.pop_front().ok_or(BinaryConvertError::length())),
+				_ => length_stack.pop_front().ok_or(BinaryConvertError::length())?,
 			};
 			let key = if key_size == 0 {
-				try!(K::from_empty_bytes())
+				K::from_empty_bytes()?
 			} else {
 				if index + key_size > buffer.len() {
 					return Err(BinaryConvertError::boundaries())
 				}
-				try!(K::from_bytes(&buffer[index..index+key_size], length_stack))
+				K::from_bytes(&buffer[index..index+key_size], length_stack)?
 			};
 			index = index + key_size;
 
 			let val_size = match V::len_params() {
 				0 => mem::size_of::<V>(),
-				_ => try!(length_stack.pop_front().ok_or(BinaryConvertError::length())),
+				_ => length_stack.pop_front().ok_or(BinaryConvertError::length())?,
 			};
 			let val = if val_size == 0 {
-				try!(V::from_empty_bytes())
+				V::from_empty_bytes()?
 			} else {
 				if index + val_size > buffer.len() {
 					return Err(BinaryConvertError::boundaries())
 				}
-				try!(V::from_bytes(&buffer[index..index+val_size], length_stack))
+				V::from_bytes(&buffer[index..index+val_size], length_stack)?
 			};
 			result.insert(key, val);
 			index = index + val_size;
@@ -344,7 +344,7 @@ impl<T> BinaryConvertable for VecDeque<T> where T: BinaryConvertable {
 			};
 			if next_size > 0 {
 				let item_end = offset + next_size;
-				try!(item.to_bytes(&mut buffer[offset..item_end], length_stack));
+				item.to_bytes(&mut buffer[offset..item_end], length_stack)?;
 				offset = item_end;
 			}
 		}
@@ -364,16 +364,16 @@ impl<T> BinaryConvertable for VecDeque<T> where T: BinaryConvertable {
 		loop {
 			let next_size = match T::len_params() {
 				0 => mem::size_of::<T>(),
-				_ => try!(length_stack.pop_front().ok_or(BinaryConvertError::length())),
+				_ => length_stack.pop_front().ok_or(BinaryConvertError::length())?,
 			};
 			let item = if next_size == 0 {
-				try!(T::from_empty_bytes())
+				T::from_empty_bytes()?
 			}
 			else {
 				if index + next_size > buffer.len() {
 					return Err(BinaryConvertError::boundaries())
 				}
-				try!(T::from_bytes(&buffer[index..index+next_size], length_stack))
+				T::from_bytes(&buffer[index..index+next_size], length_stack)?
 			};
 			result.push_back(item);
 
@@ -413,7 +413,7 @@ impl<T> BinaryConvertable for Vec<T> where T: BinaryConvertable {
 			};
 			if next_size > 0 {
 				let item_end = offset + next_size;
-				try!(item.to_bytes(&mut buffer[offset..item_end], length_stack));
+				item.to_bytes(&mut buffer[offset..item_end], length_stack)?;
 				offset = item_end;
 			}
 		}
@@ -433,16 +433,16 @@ impl<T> BinaryConvertable for Vec<T> where T: BinaryConvertable {
 		loop {
 			let next_size = match T::len_params() {
 				0 => mem::size_of::<T>(),
-				_ => try!(length_stack.pop_front().ok_or(BinaryConvertError::length())),
+				_ => length_stack.pop_front().ok_or(BinaryConvertError::length())?,
 			};
 			let item = if next_size == 0 {
-				try!(T::from_empty_bytes())
+				T::from_empty_bytes()?
 			}
 			else {
 				if index + next_size > buffer.len() {
 					return Err(BinaryConvertError::boundaries())
 				}
-				try!(T::from_bytes(&buffer[index..index+next_size], length_stack))
+				T::from_bytes(&buffer[index..index+next_size], length_stack)?
 			};
 			result.push(item);
 
@@ -498,13 +498,13 @@ impl<T> BinaryConvertable for Range<T> where T: BinaryConvertable {
 	}
 
 	fn to_bytes(&self, buffer: &mut[u8], length_stack: &mut VecDeque<usize>) -> Result<(), BinaryConvertError> {
-		try!(self.start.to_bytes(&mut buffer[..mem::size_of::<T>()], length_stack));
-		try!(self.end.to_bytes(&mut buffer[mem::size_of::<T>() + 1..], length_stack));
+		self.start.to_bytes(&mut buffer[..mem::size_of::<T>()], length_stack)?;
+		self.end.to_bytes(&mut buffer[mem::size_of::<T>() + 1..], length_stack)?;
 		Ok(())
 	}
 
 	fn from_bytes(buffer: &[u8], length_stack: &mut VecDeque<usize>) -> Result<Self, BinaryConvertError> {
-		Ok(try!(T::from_bytes(&buffer[..mem::size_of::<T>()], length_stack))..try!(T::from_bytes(&buffer[mem::size_of::<T>()+1..], length_stack)))
+		Ok(T::from_bytes(&buffer[..mem::size_of::<T>()], length_stack)?..T::from_bytes(&buffer[mem::size_of::<T>()+1..], length_stack)?)
 	}
 
 	fn len_params() -> usize {
@@ -519,15 +519,15 @@ impl<T> BinaryConvertable for ::std::cell::RefCell<T> where T: BinaryConvertable
 	}
 
 	fn from_empty_bytes() -> Result<Self, BinaryConvertError> {
-		Ok(::std::cell::RefCell::new(try!(T::from_empty_bytes())))
+		Ok(::std::cell::RefCell::new(T::from_empty_bytes()?))
 	}
 
 	fn from_bytes(buffer: &[u8], length_stack: &mut VecDeque<usize>) -> Result<Self, BinaryConvertError> {
-		Ok(::std::cell::RefCell::new(try!(T::from_bytes(buffer, length_stack))))
+		Ok(::std::cell::RefCell::new(T::from_bytes(buffer, length_stack)?))
 	}
 
 	fn to_bytes(&self, buffer: &mut [u8], length_stack: &mut VecDeque<usize>) -> Result<(), BinaryConvertError> {
-		try!(self.borrow().to_bytes(buffer, length_stack));
+		self.borrow().to_bytes(buffer, length_stack)?;
 		Ok(())
 	}
 
@@ -542,15 +542,15 @@ impl<T> BinaryConvertable for ::std::cell::Cell<T> where T: BinaryConvertable +
 	}
 
 	fn from_empty_bytes() -> Result<Self, BinaryConvertError> {
-		Ok(::std::cell::Cell::new(try!(T::from_empty_bytes())))
+		Ok(::std::cell::Cell::new(T::from_empty_bytes()?))
 	}
 
 	fn from_bytes(buffer: &[u8], length_stack: &mut VecDeque<usize>) -> Result<Self, BinaryConvertError> {
-		Ok(::std::cell::Cell::new(try!(T::from_bytes(buffer, length_stack))))
+		Ok(::std::cell::Cell::new(T::from_bytes(buffer, length_stack)?))
 	}
 
 	fn to_bytes(&self, buffer: &mut [u8], length_stack: &mut VecDeque<usize>) -> Result<(), BinaryConvertError> {
-		try!(self.get().to_bytes(buffer, length_stack));
+		self.get().to_bytes(buffer, length_stack)?;
 		Ok(())
 	}
 
@@ -596,34 +596,33 @@ pub fn deserialize_from<T, R>(r: &mut R) -> Result<T, BinaryError>
 			let fixed_size = mem::size_of::<T>();
 			let mut payload_buffer = Vec::with_capacity(fixed_size);
 			unsafe { payload_buffer.set_len(fixed_size); }
-			let bytes_read = try!(r.read(&mut payload_buffer));
+			let bytes_read = r.read(&mut payload_buffer)?;
 			if bytes_read != mem::size_of::<T>() {
 				return Err(BinaryError::Serialization(BinaryConvertError::size(fixed_size, bytes_read)))
 			}
-			Ok(try!(T::from_bytes(&payload_buffer[..], &mut fake_stack)))
+			Ok(T::from_bytes(&payload_buffer[..], &mut fake_stack)?)
 		},
 		_ => {
 			let mut payload = Vec::new();
-			try!(r.read_to_end(&mut payload));
+			r.read_to_end(&mut payload)?;
 
-			let stack_len = try!(u64::from_bytes(&payload[0..8], &mut fake_stack)) as usize;
+			let stack_len = u64::from_bytes(&payload[0..8], &mut fake_stack)? as usize;
 			let mut length_stack = VecDeque::<usize>::with_capacity(stack_len);
 
 			if stack_len > 0 {
 				for idx in 0..stack_len {
-					let stack_item = try!(u64::from_bytes(&payload[8 + idx*8..8 + (idx+1)*8], &mut fake_stack));
+					let stack_item = u64::from_bytes(&payload[8 + idx*8..8 + (idx+1)*8], &mut fake_stack)?;
 					length_stack.push_back(stack_item as usize);
 				}
 			}
 
-			//try!(r.read(&mut size_buffer).map_err(|_| BinaryConvertError));
-			let size = try!(u64::from_bytes(&payload[8+stack_len*8..16+stack_len*8], &mut fake_stack)) as usize;
+			let size = u64::from_bytes(&payload[8+stack_len*8..16+stack_len*8], &mut fake_stack)? as usize;
 			match size {
 				0 => {
-					Ok(try!(T::from_empty_bytes()))
+					Ok(T::from_empty_bytes()?)
 				},
 				_ => {
-					Ok(try!(T::from_bytes(&payload[16+stack_len*8..], &mut length_stack)))
+					Ok(T::from_bytes(&payload[16+stack_len*8..], &mut length_stack)?)
 				}
 			}
 		},
@@ -647,8 +646,8 @@ pub fn serialize_into<T, W>(t: &T, w: &mut W) -> Result<(), BinaryError>
 			let fixed_size = mem::size_of::<T>();
 			let mut buffer = Vec::with_capacity(fixed_size);
 			unsafe { buffer.set_len(fixed_size); }
-			try!(t.to_bytes(&mut buffer[..], &mut fake_stack));
-			try!(w.write(&buffer[..]));
+			t.to_bytes(&mut buffer[..], &mut fake_stack)?;
+			w.write(&buffer[..])?;
 			Ok(())
 		},
 		_ => {
@@ -657,37 +656,37 @@ pub fn serialize_into<T, W>(t: &T, w: &mut W) -> Result<(), BinaryError>
 
 			let size = t.size();
 			if size == 0 {
-				try!(w.write(&size_buffer));
-				try!(w.write(&size_buffer));
+				w.write(&size_buffer)?;
+				w.write(&size_buffer)?;
 				return Ok(());
 			}
 
 			let mut buffer = Vec::with_capacity(size);
 			unsafe { buffer.set_len(size); }
-			try!(t.to_bytes(&mut buffer[..], &mut length_stack));
+			t.to_bytes(&mut buffer[..], &mut length_stack)?;
 
 			let stack_len = length_stack.len();
-			try!((stack_len as u64).to_bytes(&mut size_buffer[..], &mut fake_stack));
-			try!(w.write(&size_buffer[..]));
+			(stack_len as u64).to_bytes(&mut size_buffer[..], &mut fake_stack)?;
+			w.write(&size_buffer[..])?;
 			if stack_len > 0 {
 				let mut header_buffer = Vec::with_capacity(stack_len * 8);
 				unsafe {  header_buffer.set_len(stack_len * 8); };
-				try!((stack_len as u64).to_bytes(&mut header_buffer[0..8], &mut fake_stack));
+				(stack_len as u64).to_bytes(&mut header_buffer[0..8], &mut fake_stack)?;
 				let mut idx = 0;
 				loop {
 					match length_stack.pop_front() {
-						Some(val) => try!((val as u64).to_bytes(&mut header_buffer[idx * 8..(idx+1) * 8], &mut fake_stack)),
+						Some(val) => (val as u64).to_bytes(&mut header_buffer[idx * 8..(idx+1) * 8], &mut fake_stack)?,
 						None => { break; }
 					}
 					idx = idx + 1;
 				}
-				try!(w.write(&header_buffer[..]));
+				w.write(&header_buffer[..])?;
 			}
 
-			try!((size as u64).to_bytes(&mut size_buffer[..], &mut fake_stack));
-			try!(w.write(&size_buffer[..]));
+			(size as u64).to_bytes(&mut size_buffer[..], &mut fake_stack)?;
+			w.write(&size_buffer[..])?;
 
-			try!(w.write(&buffer[..]));
+			w.write(&buffer[..])?;
 
 			Ok(())
 		},
@@ -697,7 +696,7 @@ pub fn serialize_into<T, W>(t: &T, w: &mut W) -> Result<(), BinaryError>
 pub fn serialize<T: BinaryConvertable>(t: &T) -> Result<Vec<u8>, BinaryError> {
 	use std::io::Cursor;
 	let mut buff = Cursor::new(Vec::new());
-	try!(serialize_into(t, &mut buff));
+	serialize_into(t, &mut buff)?;
 	let into_inner = buff.into_inner();
 	Ok(into_inner)
 }

json/src/hash.rs

@@ -54,12 +54,12 @@ macro_rules! impl_hash {
 						let value = match value.len() {
 							0 => $inner::from(0),
 							2 if value == "0x" => $inner::from(0),
-							_ if value.starts_with("0x") => try!($inner::from_str(&value[2..]).map_err(|_| {
+							_ if value.starts_with("0x") => $inner::from_str(&value[2..]).map_err(|_| {
 								Error::custom(format!("Invalid hex value {}.", value).as_str())
-							})),
-							_ => try!($inner::from_str(value).map_err(|_| {
+							})?,
+							_ => $inner::from_str(value).map_err(|_| {
 								Error::custom(format!("Invalid hex value {}.", value).as_str())
-							}))
+							})?,
 						};
 
 						Ok($name(value))

json/src/trie/input.rs

@@ -46,16 +46,16 @@ impl Visitor for InputVisitor {
 		let mut result = BTreeMap::new();
 
 		loop {
-			let key_str: Option<String> = try!(visitor.visit_key());
+			let key_str: Option<String> = visitor.visit_key()?;
 			let key = match key_str {
-				Some(ref k) if k.starts_with("0x") => try!(Bytes::from_str(k).map_err(Error::custom)),
+				Some(ref k) if k.starts_with("0x") => Bytes::from_str(k).map_err(Error::custom)?,
 				Some(k) => Bytes::new(k.into_bytes()),
 				None => { break; }
 			};
 
-			let val_str: Option<String> = try!(visitor.visit_value());
+			let val_str: Option<String> = visitor.visit_value()?;
 			let val = match val_str {
-				Some(ref v) if v.starts_with("0x") => Some(try!(Bytes::from_str(v).map_err(Error::custom))),
+				Some(ref v) if v.starts_with("0x") => Some(Bytes::from_str(v).map_err(Error::custom)?),
 				Some(v) => Some(Bytes::new(v.into_bytes())),
 				None => None,
 			};
@@ -63,7 +63,7 @@ impl Visitor for InputVisitor {
 			result.insert(key, val);
 		}
 
-		try!(visitor.end());
+		visitor.end()?;
 
 		let input = Input {
 			data: result
@@ -76,7 +76,7 @@ impl Visitor for InputVisitor {
 		let mut result = BTreeMap::new();
 
 		loop {
-			let keyval: Option<Vec<Option<String>>> = try!(visitor.visit());
+			let keyval: Option<Vec<Option<String>>> = visitor.visit()?;
 			let keyval = match keyval {
 				Some(k) => k,
 				_ => { break; },
@@ -90,13 +90,13 @@ impl Visitor for InputVisitor {
 			let ref val_str: Option<String> = keyval[1];
 
 			let key = match *key_str {
-				Some(ref k) if k.starts_with("0x") => try!(Bytes::from_str(k).map_err(Error::custom)),
+				Some(ref k) if k.starts_with("0x") => Bytes::from_str(k).map_err(Error::custom)?,
 				Some(ref k) => Bytes::new(k.clone().into_bytes()),
 				None => { break; }
 			};
 
 			let val = match *val_str {
-				Some(ref v) if v.starts_with("0x") => Some(try!(Bytes::from_str(v).map_err(Error::custom))),
+				Some(ref v) if v.starts_with("0x") => Some(Bytes::from_str(v).map_err(Error::custom)?),
 				Some(ref v) => Some(Bytes::new(v.clone().into_bytes())),
 				None => None,
 			};
@@ -104,7 +104,7 @@ impl Visitor for InputVisitor {
 			result.insert(key, val);
 		}
 
-		try!(visitor.end());
+		visitor.end()?;
 
 		let input = Input {
 			data: result

json/src/uint.rs

@@ -69,12 +69,12 @@ impl Visitor for UintVisitor {
 		let value = match value.len() {
 			0 => U256::from(0),
 			2 if value.starts_with("0x") => U256::from(0),
-			_ if value.starts_with("0x") => try!(U256::from_str(&value[2..]).map_err(|_| {
+			_ if value.starts_with("0x") => U256::from_str(&value[2..]).map_err(|_| {
 				Error::custom(format!("Invalid hex value {}.", value).as_str())
-			})),
-			_ => try!(U256::from_dec_str(value).map_err(|_| {
+			})?,
+			_ => U256::from_dec_str(value).map_err(|_| {
 				Error::custom(format!("Invalid decimal value {}.", value).as_str())
-			}))
+			})?
 		};
 
 		Ok(Uint(value))

logger/src/lib.rs

@@ -86,10 +86,9 @@ pub fn setup_log(config: &Config) -> Result<Arc<RotatingLogger>, String> {
 	let mut open_options = fs::OpenOptions::new();
 
 	let maybe_file = match config.file.as_ref() {
-		Some(f) => Some(try!(open_options
+		Some(f) => Some(open_options
 			.append(true).create(true).open(f)
-			.map_err(|_| format!("Cannot write to log file given: {}", f))
-		)),
+			.map_err(|_| format!("Cannot write to log file given: {}", f))?),
 		None => None,
 	};
 

parity/account.rs

@@ -70,7 +70,7 @@ pub fn execute(cmd: AccountCmd) -> Result<String, String> {
 }
 
 fn keys_dir(path: String, spec: SpecType) -> Result<DiskDirectory, String> {
-	let spec = try!(spec.spec());
+	let spec = spec.spec()?;
 	let mut path = PathBuf::from(&path);
 	path.push(spec.data_dir);
 	DiskDirectory::create(path).map_err(|e| format!("Could not open keys directory: {}", e))
@@ -85,20 +85,20 @@ fn secret_store(dir: Box<DiskDirectory>, iterations: Option<u32>) -> Result<EthS
 
 fn new(n: NewAccount) -> Result<String, String> {
 	let password: String = match n.password_file {
-		Some(file) => try!(password_from_file(file)),
-		None => try!(password_prompt()),
+		Some(file) => password_from_file(file)?,
+		None => password_prompt()?,
 	};
 
-	let dir = Box::new(try!(keys_dir(n.path, n.spec)));
-	let secret_store = Box::new(try!(secret_store(dir, Some(n.iterations))));
+	let dir = Box::new(keys_dir(n.path, n.spec)?);
+	let secret_store = Box::new(secret_store(dir, Some(n.iterations))?);
 	let acc_provider = AccountProvider::new(secret_store);
-	let new_account = try!(acc_provider.new_account(&password).map_err(|e| format!("Could not create new account: {}", e)));
+	let new_account = acc_provider.new_account(&password).map_err(|e| format!("Could not create new account: {}", e))?;
 	Ok(format!("{:?}", new_account))
 }
 
 fn list(list_cmd: ListAccounts) -> Result<String, String> {
-	let dir = Box::new(try!(keys_dir(list_cmd.path, list_cmd.spec)));
-	let secret_store = Box::new(try!(secret_store(dir, None)));
+	let dir = Box::new(keys_dir(list_cmd.path, list_cmd.spec)?);
+	let secret_store = Box::new(secret_store(dir, None)?);
 	let acc_provider = AccountProvider::new(secret_store);
 	let accounts = acc_provider.accounts();
 	let result = accounts.into_iter()
@@ -110,11 +110,11 @@ fn list(list_cmd: ListAccounts) -> Result<String, String> {
 }
 
 fn import(i: ImportAccounts) -> Result<String, String> {
-	let to = try!(keys_dir(i.to, i.spec));
+	let to = keys_dir(i.to, i.spec)?;
 	let mut imported = 0;
 	for path in &i.from {
 		let from = DiskDirectory::at(path);
-		imported += try!(import_accounts(&from, &to).map_err(|_| "Importing accounts failed.")).len();
+		imported += import_accounts(&from, &to).map_err(|_| "Importing accounts failed.")?.len();
 	}
 	Ok(format!("{} account(s) imported", imported))
 }
@@ -123,8 +123,8 @@ fn import_geth(i: ImportFromGethAccounts) -> Result<String, String> {
 	use std::io::ErrorKind;
 	use ethcore::ethstore::Error;
 
-	let dir = Box::new(try!(keys_dir(i.to, i.spec)));
-	let secret_store = Box::new(try!(secret_store(dir, None)));
+	let dir = Box::new(keys_dir(i.to, i.spec)?);
+	let secret_store = Box::new(secret_store(dir, None)?);
 	let geth_accounts = read_geth_accounts(i.testnet);
 	match secret_store.import_geth_accounts(geth_accounts, i.testnet) {
 		Ok(v) => Ok(format!("Successfully imported {} account(s) from geth.", v.len())),

parity/blockchain.rs

@@ -149,7 +149,7 @@ fn execute_import(cmd: ImportBlockchain) -> Result<(), String> {
 	let panic_handler = PanicHandler::new_in_arc();
 
 	// load spec file
-	let spec = try!(cmd.spec.spec());
+	let spec = cmd.spec.spec()?;
 
 	// load genesis hash
 	let genesis_hash = spec.genesis_header().hash();
@@ -161,7 +161,7 @@ fn execute_import(cmd: ImportBlockchain) -> Result<(), String> {
 	let user_defaults_path = db_dirs.user_defaults_path();
 
 	// load user defaults
-	let mut user_defaults = try!(UserDefaults::load(&user_defaults_path));
+	let mut user_defaults = UserDefaults::load(&user_defaults_path)?;
 
 	fdlimit::raise_fd_limit();
 
@@ -169,20 +169,20 @@ fn execute_import(cmd: ImportBlockchain) -> Result<(), String> {
 	let algorithm = cmd.pruning.to_algorithm(&user_defaults);
 
 	// check if tracing is on
-	let tracing = try!(tracing_switch_to_bool(cmd.tracing, &user_defaults));
+	let tracing = tracing_switch_to_bool(cmd.tracing, &user_defaults)?;
 
 	// check if fatdb is on
-	let fat_db = try!(fatdb_switch_to_bool(cmd.fat_db, &user_defaults, algorithm));
+	let fat_db = fatdb_switch_to_bool(cmd.fat_db, &user_defaults, algorithm)?;
 
 	// prepare client and snapshot paths.
 	let client_path = db_dirs.client_path(algorithm);
 	let snapshot_path = db_dirs.snapshot_path();
 
 	// execute upgrades
-	try!(execute_upgrades(&cmd.dirs.base, &db_dirs, algorithm, cmd.compaction.compaction_profile(db_dirs.db_root_path().as_path())));
+	execute_upgrades(&cmd.dirs.base, &db_dirs, algorithm, cmd.compaction.compaction_profile(db_dirs.db_root_path().as_path()))?;
 
 	// create dirs used by parity
-	try!(cmd.dirs.create_dirs(false, false));
+	cmd.dirs.create_dirs(false, false)?;
 
 	// prepare client config
 	let mut client_config = to_client_config(
@@ -202,14 +202,14 @@ fn execute_import(cmd: ImportBlockchain) -> Result<(), String> {
 	client_config.queue.verifier_settings = cmd.verifier_settings;
 
 	// build client
-	let service = try!(ClientService::start(
+	let service = ClientService::start(
 		client_config,
 		&spec,
 		&client_path,
 		&snapshot_path,
 		&cmd.dirs.ipc_path(),
 		Arc::new(Miner::with_spec(&spec)),
-	).map_err(|e| format!("Client service error: {:?}", e)));
+	).map_err(|e| format!("Client service error: {:?}", e))?;
 
 	// free up the spec in memory.
 	drop(spec);
@@ -218,7 +218,7 @@ fn execute_import(cmd: ImportBlockchain) -> Result<(), String> {
 	let client = service.client();
 
 	let mut instream: Box<io::Read> = match cmd.file_path {
-		Some(f) => Box::new(try!(fs::File::open(&f).map_err(|_| format!("Cannot open given file: {}", f)))),
+		Some(f) => Box::new(fs::File::open(&f).map_err(|_| format!("Cannot open given file: {}", f))?),
 		None => Box::new(io::stdin()),
 	};
 
@@ -230,7 +230,7 @@ fn execute_import(cmd: ImportBlockchain) -> Result<(), String> {
 	let format = match cmd.format {
 		Some(format) => format,
 		None => {
-			first_read = try!(instream.read(&mut first_bytes).map_err(|_| "Error reading from the file/stream."));
+			first_read = instream.read(&mut first_bytes).map_err(|_| "Error reading from the file/stream.")?;
 			match first_bytes[0] {
 				0xf9 => DataFormat::Binary,
 				_ => DataFormat::Hex,
@@ -262,23 +262,23 @@ fn execute_import(cmd: ImportBlockchain) -> Result<(), String> {
 				let n = if first_read > 0 {
 					first_read
 				} else {
-					try!(instream.read(&mut bytes).map_err(|_| "Error reading from the file/stream."))
+					instream.read(&mut bytes).map_err(|_| "Error reading from the file/stream.")?
 				};
 				if n == 0 { break; }
 				first_read = 0;
-				let s = try!(PayloadInfo::from(&bytes).map_err(|e| format!("Invalid RLP in the file/stream: {:?}", e))).total();
+				let s = PayloadInfo::from(&bytes).map_err(|e| format!("Invalid RLP in the file/stream: {:?}", e))?.total();
 				bytes.resize(s, 0);
-				try!(instream.read_exact(&mut bytes[n..]).map_err(|_| "Error reading from the file/stream."));
-				try!(do_import(bytes));
+				instream.read_exact(&mut bytes[n..]).map_err(|_| "Error reading from the file/stream.")?;
+				do_import(bytes)?;
 			}
 		}
 		DataFormat::Hex => {
 			for line in BufReader::new(instream).lines() {
-				let s = try!(line.map_err(|_| "Error reading from the file/stream."));
+				let s = line.map_err(|_| "Error reading from the file/stream.")?;
 				let s = if first_read > 0 {from_utf8(&first_bytes).unwrap().to_owned() + &(s[..])} else {s};
 				first_read = 0;
-				let bytes = try!(s.from_hex().map_err(|_| "Invalid hex in file/stream."));
-				try!(do_import(bytes));
+				let bytes = s.from_hex().map_err(|_| "Invalid hex in file/stream.")?;
+				do_import(bytes)?;
 			}
 		}
 	}
@@ -288,7 +288,7 @@ fn execute_import(cmd: ImportBlockchain) -> Result<(), String> {
 	user_defaults.pruning = algorithm;
 	user_defaults.tracing = tracing;
 	user_defaults.fat_db = fat_db;
-	try!(user_defaults.save(&user_defaults_path));
+	user_defaults.save(&user_defaults_path)?;
 
 	let report = client.report();
 
@@ -318,7 +318,7 @@ fn start_client(
 ) -> Result<ClientService, String> {
 
 	// load spec file
-	let spec = try!(spec.spec());
+	let spec = spec.spec()?;
 
 	// load genesis hash
 	let genesis_hash = spec.genesis_header().hash();
@@ -330,7 +330,7 @@ fn start_client(
 	let user_defaults_path = db_dirs.user_defaults_path();
 
 	// load user defaults
-	let user_defaults = try!(UserDefaults::load(&user_defaults_path));
+	let user_defaults = UserDefaults::load(&user_defaults_path)?;
 
 	fdlimit::raise_fd_limit();
 
@@ -338,32 +338,32 @@ fn start_client(
 	let algorithm = pruning.to_algorithm(&user_defaults);
 
 	// check if tracing is on
-	let tracing = try!(tracing_switch_to_bool(tracing, &user_defaults));
+	let tracing = tracing_switch_to_bool(tracing, &user_defaults)?;
 
 	// check if fatdb is on
-	let fat_db = try!(fatdb_switch_to_bool(fat_db, &user_defaults, algorithm));
+	let fat_db = fatdb_switch_to_bool(fat_db, &user_defaults, algorithm)?;
 
 	// prepare client and snapshot paths.
 	let client_path = db_dirs.client_path(algorithm);
 	let snapshot_path = db_dirs.snapshot_path();
 
 	// execute upgrades
-	try!(execute_upgrades(&dirs.base, &db_dirs, algorithm, compaction.compaction_profile(db_dirs.db_root_path().as_path())));
+	execute_upgrades(&dirs.base, &db_dirs, algorithm, compaction.compaction_profile(db_dirs.db_root_path().as_path()))?;
 
 	// create dirs used by parity
-	try!(dirs.create_dirs(false, false));
+	dirs.create_dirs(false, false)?;
 
 	// prepare client config
 	let client_config = to_client_config(&cache_config, Mode::Active, tracing, fat_db, compaction, wal, VMType::default(), "".into(), algorithm, pruning_history, true);
 
-	let service = try!(ClientService::start(
+	let service = ClientService::start(
 		client_config,
 		&spec,
 		&client_path,
 		&snapshot_path,
 		&dirs.ipc_path(),
 		Arc::new(Miner::with_spec(&spec)),
-	).map_err(|e| format!("Client service error: {:?}", e)));
+	).map_err(|e| format!("Client service error: {:?}", e))?;
 
 	drop(spec);
 	Ok(service)
@@ -371,7 +371,7 @@ fn start_client(
 
 fn execute_export(cmd: ExportBlockchain) -> Result<(), String> {
 	// Setup panic handler
-	let service = try!(start_client(cmd.dirs, cmd.spec, cmd.pruning, cmd.pruning_history, cmd.tracing, cmd.fat_db, cmd.compaction, cmd.wal, cmd.cache_config));
+	let service = start_client(cmd.dirs, cmd.spec, cmd.pruning, cmd.pruning_history, cmd.tracing, cmd.fat_db, cmd.compaction, cmd.wal, cmd.cache_config)?;
 	let panic_handler = PanicHandler::new_in_arc();
 	let format = cmd.format.unwrap_or_default();
 
@@ -379,18 +379,18 @@ fn execute_export(cmd: ExportBlockchain) -> Result<(), String> {
 	let client = service.client();
 
 	let mut out: Box<io::Write> = match cmd.file_path {
-		Some(f) => Box::new(try!(fs::File::create(&f).map_err(|_| format!("Cannot write to file given: {}", f)))),
+		Some(f) => Box::new(fs::File::create(&f).map_err(|_| format!("Cannot write to file given: {}", f))?),
 		None => Box::new(io::stdout()),
 	};
 
-	let from = try!(client.block_number(cmd.from_block).ok_or("From block could not be found"));
-	let to = try!(client.block_number(cmd.to_block).ok_or("To block could not be found"));
+	let from = client.block_number(cmd.from_block).ok_or("From block could not be found")?;
+	let to = client.block_number(cmd.to_block).ok_or("To block could not be found")?;
 
 	for i in from..(to + 1) {
 		if i % 10000 == 0 {
 			info!("#{}", i);
 		}
-		let b = try!(client.block(BlockId::Number(i)).ok_or("Error exporting incomplete chain"));
+		let b = client.block(BlockId::Number(i)).ok_or("Error exporting incomplete chain")?;
 		match format {
 			DataFormat::Binary => { out.write(&b).expect("Couldn't write to stream."); }
 			DataFormat::Hex => { out.write_fmt(format_args!("{}", b.pretty())).expect("Couldn't write to stream."); }
@@ -403,14 +403,14 @@ fn execute_export(cmd: ExportBlockchain) -> Result<(), String> {
 
 fn execute_export_state(cmd: ExportState) -> Result<(), String> {
 	// Setup panic handler
-	let service = try!(start_client(cmd.dirs, cmd.spec, cmd.pruning, cmd.pruning_history, cmd.tracing, cmd.fat_db, cmd.compaction, cmd.wal, cmd.cache_config));
+	let service = start_client(cmd.dirs, cmd.spec, cmd.pruning, cmd.pruning_history, cmd.tracing, cmd.fat_db, cmd.compaction, cmd.wal, cmd.cache_config)?;
 	let panic_handler = PanicHandler::new_in_arc();
 
 	panic_handler.forward_from(&service);
 	let client = service.client();
 
 	let mut out: Box<io::Write> = match cmd.file_path {
-		Some(f) => Box::new(try!(fs::File::create(&f).map_err(|_| format!("Cannot write to file given: {}", f)))),
+		Some(f) => Box::new(fs::File::create(&f).map_err(|_| format!("Cannot write to file given: {}", f))?),
 		None => Box::new(io::stdout()),
 	};
 
@@ -420,7 +420,7 @@ fn execute_export_state(cmd: ExportState) -> Result<(), String> {
 
 	out.write_fmt(format_args!("{{ \"state\": [", )).expect("Couldn't write to stream.");
 	loop {
-		let accounts = try!(client.list_accounts(at, last.as_ref(), 1000).ok_or("Specified block not found"));
+		let accounts = client.list_accounts(at, last.as_ref(), 1000).ok_or("Specified block not found")?;
 		if accounts.is_empty() {
 			break;
 		}
@@ -450,7 +450,7 @@ fn execute_export_state(cmd: ExportState) -> Result<(), String> {
 					out.write_fmt(format_args!(", \"storage\": {{")).expect("Write error");
 					let mut last_storage: Option<H256> = None;
 					loop {
-						let keys = try!(client.list_storage(at, &account, last_storage.as_ref(), 1000).ok_or("Specified block not found"));
+						let keys = client.list_storage(at, &account, last_storage.as_ref(), 1000).ok_or("Specified block not found")?;
 						if keys.is_empty() {
 							break;
 						}
@@ -482,14 +482,14 @@ fn execute_export_state(cmd: ExportState) -> Result<(), String> {
 }
 
 pub fn kill_db(cmd: KillBlockchain) -> Result<(), String> {
-	let spec = try!(cmd.spec.spec());
+	let spec = cmd.spec.spec()?;
 	let genesis_hash = spec.genesis_header().hash();
 	let db_dirs = cmd.dirs.database(genesis_hash, None, spec.data_dir);
 	let user_defaults_path = db_dirs.user_defaults_path();
-	let user_defaults = try!(UserDefaults::load(&user_defaults_path));
+	let user_defaults = UserDefaults::load(&user_defaults_path)?;
 	let algorithm = cmd.pruning.to_algorithm(&user_defaults);
 	let dir = db_dirs.db_path(algorithm);
-	try!(fs::remove_dir_all(&dir).map_err(|e| format!("Error removing database: {:?}", e)));
+	fs::remove_dir_all(&dir).map_err(|e| format!("Error removing database: {:?}", e))?;
 	info!("Database deleted.");
 	Ok(())
 }

parity/boot.rs

@@ -53,9 +53,7 @@ pub fn payload<B: ipc::BinaryConvertable>() -> Result<B, BootError> {
 	use std::io::Read;
 
 	let mut buffer = Vec::new();
-	try!(
-		io::stdin().read_to_end(&mut buffer).map_err(BootError::ReadArgs)
-	);
+	io::stdin().read_to_end(&mut buffer).map_err(BootError::ReadArgs)?;
 
 	ipc::binary::deserialize::<B>(&buffer).map_err(BootError::DecodeArgs)
 }

parity/cli/usage.rs

@@ -137,7 +137,7 @@ macro_rules! usage {
 		impl Args {
 
 			pub fn parse<S: AsRef<str>>(command: &[S]) -> Result<Self, ArgsError> {
-				let raw_args = try!(RawArgs::parse(command));
+				let raw_args = RawArgs::parse(command)?;
 
 				// Skip loading config file if no_config flag is specified
 				if raw_args.flag_no_config {
@@ -151,8 +151,8 @@ macro_rules! usage {
 					(Ok(mut file), _) => {
 						println_stderr!("Loading config file from {}", &config_file);
 						let mut config = String::new();
-						try!(file.read_to_string(&mut config).map_err(|e| ArgsError::Config(config_file, e)));
-						try!(Self::parse_config(&config))
+						file.read_to_string(&mut config).map_err(|e| ArgsError::Config(config_file, e))?;
+						Self::parse_config(&config)?
 					},
 					// Don't display error in case default config cannot be loaded.
 					(Err(_), false) => Config::default(),
@@ -172,7 +172,7 @@ macro_rules! usage {
 
 			#[cfg(test)]
 			fn parse_with_config<S: AsRef<str>>(command: &[S], config: Config) -> Result<Self, ArgsError> {
-				Ok(try!(RawArgs::parse(command)).into_args(config))
+				RawArgs::parse(command).map(|raw| raw.into_args(config)).map_err(ArgsError::Docopt)
 			}
 
 			fn parse_config(config: &str) -> Result<Config, ArgsError> {

parity/configuration.rs

@@ -85,7 +85,7 @@ pub struct Configuration {
 
 impl Configuration {
 	pub fn parse<S: AsRef<str>>(command: &[S]) -> Result<Self, ArgsError> {
-		let args = try!(Args::parse(command));
+		let args = Args::parse(command)?;
 
 		let config = Configuration {
 			args: args,
@@ -96,29 +96,29 @@ impl Configuration {
 
 	pub fn into_command(self) -> Result<Execute, String> {
 		let dirs = self.directories();
-		let pruning = try!(self.args.flag_pruning.parse());
+		let pruning = self.args.flag_pruning.parse()?;
 		let pruning_history = self.args.flag_pruning_history;
-		let vm_type = try!(self.vm_type());
-		let mode = match self.args.flag_mode.as_ref() { "last" => None, mode => Some(try!(to_mode(&mode, self.args.flag_mode_timeout, self.args.flag_mode_alarm))), };
-		let update_policy = try!(self.update_policy());
-		let miner_options = try!(self.miner_options());
+		let vm_type = self.vm_type()?;
+		let mode = match self.args.flag_mode.as_ref() { "last" => None, mode => Some(to_mode(&mode, self.args.flag_mode_timeout, self.args.flag_mode_alarm)?), };
+		let update_policy = self.update_policy()?;
+		let miner_options = self.miner_options()?;
 		let logger_config = self.logger_config();
-		let http_conf = try!(self.http_config());
-		let ipc_conf = try!(self.ipc_config());
-		let net_conf = try!(self.net_config());
+		let http_conf = self.http_config()?;
+		let ipc_conf = self.ipc_config()?;
+		let net_conf = self.net_config()?;
 		let network_id = self.network_id();
 		let cache_config = self.cache_config();
-		let spec = try!(self.chain().parse());
-		let tracing = try!(self.args.flag_tracing.parse());
-		let fat_db = try!(self.args.flag_fat_db.parse());
-		let compaction = try!(self.args.flag_db_compaction.parse());
+		let spec = self.chain().parse()?;
+		let tracing = self.args.flag_tracing.parse()?;
+		let fat_db = self.args.flag_fat_db.parse()?;
+		let compaction = self.args.flag_db_compaction.parse()?;
 		let wal = !self.args.flag_fast_and_loose;
 		let warp_sync = self.args.flag_warp;
 		let geth_compatibility = self.args.flag_geth;
 		let ui_address = self.ui_port().map(|port| (self.ui_interface(), port));
 		let dapps_conf = self.dapps_config();
 		let signer_conf = self.signer_config();
-		let format = try!(self.format());
+		let format = self.format()?;
 
 		let cmd = if self.args.flag_version {
 			Cmd::Version
@@ -237,8 +237,8 @@ impl Configuration {
 					wal: wal,
 					tracing: tracing,
 					fat_db: fat_db,
-					from_block: try!(to_block_id(&self.args.flag_from)),
-					to_block: try!(to_block_id(&self.args.flag_to)),
+					from_block: to_block_id(&self.args.flag_from)?,
+					to_block: to_block_id(&self.args.flag_to)?,
 					check_seal: !self.args.flag_no_seal_check,
 				};
 				Cmd::Blockchain(BlockchainCmd::Export(export_cmd))
@@ -255,7 +255,7 @@ impl Configuration {
 					wal: wal,
 					tracing: tracing,
 					fat_db: fat_db,
-					at: try!(to_block_id(&self.args.flag_at)),
+					at: to_block_id(&self.args.flag_at)?,
 					storage: !self.args.flag_no_storage,
 					code: !self.args.flag_no_code,
 					min_balance: self.args.flag_min_balance.and_then(|s| to_u256(&s).ok()),
@@ -278,7 +278,7 @@ impl Configuration {
 				file_path: self.args.arg_file.clone(),
 				wal: wal,
 				kind: snapshot::Kind::Take,
-				block_at: try!(to_block_id(&self.args.flag_at)),
+				block_at: to_block_id(&self.args.flag_at)?,
 			};
 			Cmd::Snapshot(snapshot_cmd)
 		} else if self.args.cmd_restore {
@@ -294,7 +294,7 @@ impl Configuration {
 				file_path: self.args.arg_file.clone(),
 				wal: wal,
 				kind: snapshot::Kind::Restore,
-				block_at: try!(to_block_id("latest")), // unimportant.
+				block_at: to_block_id("latest")?, // unimportant.
 			};
 			Cmd::Snapshot(restore_cmd)
 		} else {
@@ -319,9 +319,9 @@ impl Configuration {
 				ipc_conf: ipc_conf,
 				net_conf: net_conf,
 				network_id: network_id,
-				acc_conf: try!(self.accounts_config()),
-				gas_pricer: try!(self.gas_pricer_config()),
-				miner_extras: try!(self.miner_extras()),
+				acc_conf: self.accounts_config()?,
+				gas_pricer: self.gas_pricer_config()?,
+				miner_extras: self.miner_extras()?,
 				update_policy: update_policy,
 				mode: mode,
 				tracing: tracing,
@@ -362,12 +362,12 @@ impl Configuration {
 
 	fn miner_extras(&self) -> Result<MinerExtras, String> {
 		let extras = MinerExtras {
-			author: try!(self.author()),
-			extra_data: try!(self.extra_data()),
-			gas_floor_target: try!(to_u256(&self.args.flag_gas_floor_target)),
-			gas_ceil_target: try!(to_u256(&self.args.flag_gas_cap)),
+			author: self.author()?,
+			extra_data: self.extra_data()?,
+			gas_floor_target: to_u256(&self.args.flag_gas_floor_target)?,
+			gas_ceil_target: to_u256(&self.args.flag_gas_cap)?,
 			transactions_limit: self.args.flag_tx_queue_size,
-			engine_signer: try!(self.engine_signer()),
+			engine_signer: self.engine_signer()?,
 		};
 
 		Ok(extras)
@@ -383,7 +383,7 @@ impl Configuration {
 
 	fn format(&self) -> Result<Option<DataFormat>, String> {
 		match self.args.flag_format {
-			Some(ref f) => Ok(Some(try!(f.parse()))),
+			Some(ref f) => Ok(Some(f.parse()?)),
 			None => Ok(None),
 		}
 	}
@@ -451,14 +451,14 @@ impl Configuration {
 			iterations: self.args.flag_keys_iterations,
 			testnet: self.args.flag_testnet,
 			password_files: self.args.flag_password.clone(),
-			unlocked_accounts: try!(to_addresses(&self.args.flag_unlock)),
+			unlocked_accounts: to_addresses(&self.args.flag_unlock)?,
 		};
 
 		Ok(cfg)
 	}
 
 	fn miner_options(&self) -> Result<MinerOptions, String> {
-		let reseal = try!(self.args.flag_reseal_on_txs.parse::<ResealPolicy>());
+		let reseal = self.args.flag_reseal_on_txs.parse::<ResealPolicy>()?;
 
 		let options = MinerOptions {
 			new_work_notify: self.work_notify(),
@@ -466,13 +466,13 @@ impl Configuration {
 			reseal_on_external_tx: reseal.external,
 			reseal_on_own_tx: reseal.own,
 			tx_gas_limit: match self.args.flag_tx_gas_limit {
-				Some(ref d) => try!(to_u256(d)),
+				Some(ref d) => to_u256(d)?,
 				None => U256::max_value(),
 			},
 			tx_queue_size: self.args.flag_tx_queue_size,
-			tx_queue_gas_limit: try!(to_gas_limit(&self.args.flag_tx_queue_gas)),
-			tx_queue_strategy: try!(to_queue_strategy(&self.args.flag_tx_queue_strategy)),
-			pending_set: try!(to_pending_set(&self.args.flag_relay_set)),
+			tx_queue_gas_limit: to_gas_limit(&self.args.flag_tx_queue_gas)?,
+			tx_queue_strategy: to_queue_strategy(&self.args.flag_tx_queue_strategy)?,
+			pending_set: to_pending_set(&self.args.flag_relay_set)?,
 			reseal_min_period: Duration::from_millis(self.args.flag_reseal_min_period),
 			work_queue_size: self.args.flag_work_queue_size,
 			enable_resubmission: !self.args.flag_remove_solved,
@@ -513,18 +513,18 @@ impl Configuration {
 
 	fn gas_pricer_config(&self) -> Result<GasPricerConfig, String> {
 		if let Some(d) = self.args.flag_gasprice.as_ref() {
-			return Ok(GasPricerConfig::Fixed(try!(to_u256(d))));
+			return Ok(GasPricerConfig::Fixed(to_u256(d)?));
 		}
 
-		let usd_per_tx = try!(to_price(&self.args.flag_usd_per_tx));
+		let usd_per_tx = to_price(&self.args.flag_usd_per_tx)?;
 		if "auto" == self.args.flag_usd_per_eth.as_str() {
 			return Ok(GasPricerConfig::Calibrated {
 				usd_per_tx: usd_per_tx,
-				recalibration_period: try!(to_duration(self.args.flag_price_update_period.as_str())),
+				recalibration_period: to_duration(self.args.flag_price_update_period.as_str())?,
 			});
 		}
 
-		let usd_per_eth = try!(to_price(&self.args.flag_usd_per_eth));
+		let usd_per_eth = to_price(&self.args.flag_usd_per_eth)?;
 		let wei_per_usd: f32 = 1.0e18 / usd_per_eth;
 		let gas_per_tx: f32 = 21000.0;
 		let wei_per_gas: f32 = wei_per_usd * usd_per_tx / gas_per_tx;
@@ -552,8 +552,8 @@ impl Configuration {
 		match self.args.flag_reserved_peers {
 			Some(ref path) => {
 				let mut buffer = String::new();
-				let mut node_file = try!(File::open(path).map_err(|e| format!("Error opening reserved nodes file: {}", e)));
-				try!(node_file.read_to_string(&mut buffer).map_err(|_| "Error reading reserved node file"));
+				let mut node_file = File::open(path).map_err(|e| format!("Error opening reserved nodes file: {}", e))?;
+				node_file.read_to_string(&mut buffer).map_err(|_| "Error reading reserved node file")?;
 				let lines = buffer.lines().map(|s| s.trim().to_owned()).filter(|s| !s.is_empty()).collect::<Vec<_>>();
 				if let Some(invalid) = lines.iter().find(|s| !is_valid_node_url(s)) {
 					return Err(format!("Invalid node address format given for a boot node: {}", invalid));
@@ -569,7 +569,7 @@ impl Configuration {
 		let listen_address = Some(SocketAddr::new("0.0.0.0".parse().unwrap(), port));
 		let public_address = if self.args.flag_nat.starts_with("extip:") {
 			let host = &self.args.flag_nat[6..];
-			let host = try!(host.parse().map_err(|_| format!("Invalid host given with `--nat extip:{}`", host)));
+			let host = host.parse().map_err(|_| format!("Invalid host given with `--nat extip:{}`", host))?;
 			Some(SocketAddr::new(host, port))
 		} else {
 			None
@@ -580,8 +580,8 @@ impl Configuration {
 	fn net_config(&self) -> Result<NetworkConfiguration, String> {
 		let mut ret = NetworkConfiguration::new();
 		ret.nat_enabled = self.args.flag_nat == "any" || self.args.flag_nat == "upnp";
-		ret.boot_nodes = try!(to_bootnodes(&self.args.flag_bootnodes));
-		let (listen, public) = try!(self.net_addresses());
+		ret.boot_nodes = to_bootnodes(&self.args.flag_bootnodes)?;
+		let (listen, public) = self.net_addresses()?;
 		ret.listen_address = listen.map(|l| format!("{}", l));
 		ret.public_address = public.map(|p| format!("{}", p));
 		ret.use_secret = self.args.flag_node_key.as_ref().map(|s| s.parse::<Secret>().unwrap_or_else(|_| s.sha3()));
@@ -589,12 +589,12 @@ impl Configuration {
 		ret.max_peers = self.max_peers();
 		ret.min_peers = self.min_peers();
 		ret.snapshot_peers = self.snapshot_peers();
-		ret.allow_ips = try!(self.allow_ips());
+		ret.allow_ips = self.allow_ips()?;
 		ret.max_pending_peers = self.max_pending_peers();
 		let mut net_path = PathBuf::from(self.directories().base);
 		net_path.push("network");
 		ret.config_path = Some(net_path.to_str().unwrap().to_owned());
-		ret.reserved_nodes = try!(self.init_reserved_nodes());
+		ret.reserved_nodes = self.init_reserved_nodes()?;
 		ret.allow_non_reserved = !self.args.flag_reserved_only;
 		Ok(ret)
 	}
@@ -651,7 +651,7 @@ impl Configuration {
  					}
 					apis.push_str("personal");
 				}
-				try!(apis.parse())
+				apis.parse()?
 			},
 		};
 
@@ -663,7 +663,7 @@ impl Configuration {
 			enabled: !self.args.flag_jsonrpc_off && !self.args.flag_no_jsonrpc,
 			interface: self.rpc_interface(),
 			port: self.args.flag_rpcport.unwrap_or(self.args.flag_jsonrpc_port),
-			apis: try!(self.rpc_apis().parse()),
+			apis: self.rpc_apis().parse()?,
 			hosts: self.rpc_hosts(),
 			cors: self.rpc_cors(),
 		};

parity/dapps.rs

@@ -67,7 +67,7 @@ pub fn new(configuration: Configuration, deps: Dependencies) -> Result<Option<We
 	}
 
 	let url = format!("{}:{}", configuration.interface, configuration.port);
-	let addr = try!(url.parse().map_err(|_| format!("Invalid Webapps listen host/port given: {}", url)));
+	let addr = url.parse().map_err(|_| format!("Invalid Webapps listen host/port given: {}", url))?;
 
 	let auth = configuration.user.as_ref().map(|username| {
 		let password = configuration.pass.as_ref().map_or_else(|| {
@@ -80,7 +80,7 @@ pub fn new(configuration: Configuration, deps: Dependencies) -> Result<Option<We
 		(username.to_owned(), password)
 	});
 
-	Ok(Some(try!(setup_dapps_server(deps, configuration.dapps_path, &addr, configuration.hosts, auth))))
+	Ok(Some(setup_dapps_server(deps, configuration.dapps_path, &addr, configuration.hosts, auth)?))
 }
 
 pub use self::server::WebappServer;

parity/dir.rs

@@ -59,14 +59,14 @@ impl Default for Directories {
 
 impl Directories {
 	pub fn create_dirs(&self, dapps_enabled: bool, signer_enabled: bool) -> Result<(), String> {
-		try!(fs::create_dir_all(&self.base).map_err(|e| e.to_string()));
-		try!(fs::create_dir_all(&self.db).map_err(|e| e.to_string()));
-		try!(fs::create_dir_all(&self.keys).map_err(|e| e.to_string()));
+		fs::create_dir_all(&self.base).map_err(|e| e.to_string())?;
+		fs::create_dir_all(&self.db).map_err(|e| e.to_string())?;
+		fs::create_dir_all(&self.keys).map_err(|e| e.to_string())?;
 		if signer_enabled {
-			try!(fs::create_dir_all(&self.signer).map_err(|e| e.to_string()));
+			fs::create_dir_all(&self.signer).map_err(|e| e.to_string())?;
 		}
 		if dapps_enabled {
-			try!(fs::create_dir_all(&self.dapps).map_err(|e| e.to_string()));
+			fs::create_dir_all(&self.dapps).map_err(|e| e.to_string())?;
 		}
 		Ok(())
 	}

parity/helpers.rs

@@ -97,7 +97,7 @@ pub fn to_gas_limit(s: &str) -> Result<GasLimit, String> {
 	match s {
 		"auto" => Ok(GasLimit::Auto),
 		"off" => Ok(GasLimit::None),
-		other => Ok(GasLimit::Fixed(try!(to_u256(other)))),
+		other => Ok(GasLimit::Fixed(to_u256(other)?)),
 	}
 }
 
@@ -288,12 +288,12 @@ pub fn password_prompt() -> Result<String, String> {
 	print!("Type password: ");
 	flush_stdout();
 
-	let password = try!(read_password().map_err(|_| STDIN_ERROR.to_owned()));
+	let password = read_password().map_err(|_| STDIN_ERROR.to_owned())?;
 
 	print!("Repeat password: ");
 	flush_stdout();
 
-	let password_repeat = try!(read_password().map_err(|_| STDIN_ERROR.to_owned()));
+	let password_repeat = read_password().map_err(|_| STDIN_ERROR.to_owned())?;
 
 	if password != password_repeat {
 		return Err("Passwords do not match!".into());
@@ -304,7 +304,7 @@ pub fn password_prompt() -> Result<String, String> {
 
 /// Read a password from password file.
 pub fn password_from_file(path: String) -> Result<String, String> {
-	let passwords = try!(passwords_from_files(&[path]));
+	let passwords = passwords_from_files(&[path])?;
 	// use only first password from the file
 	passwords.get(0).map(String::to_owned)
 		.ok_or_else(|| "Password file seems to be empty.".to_owned())
@@ -313,7 +313,7 @@ pub fn password_from_file(path: String) -> Result<String, String> {
 /// Reads passwords from files. Treats each line as a separate password.
 pub fn passwords_from_files(files: &[String]) -> Result<Vec<String>, String> {
 	let passwords = files.iter().map(|filename| {
-		let file = try!(File::open(filename).map_err(|_| format!("{} Unable to read password file. Ensure it exists and permissions are correct.", filename)));
+		let file = File::open(filename).map_err(|_| format!("{} Unable to read password file. Ensure it exists and permissions are correct.", filename))?;
 		let reader = BufReader::new(&file);
 		let lines = reader.lines()
 			.filter_map(|l| l.ok())
@@ -321,7 +321,7 @@ pub fn passwords_from_files(files: &[String]) -> Result<Vec<String>, String> {
 			.collect::<Vec<String>>();
 		Ok(lines)
 	}).collect::<Result<Vec<Vec<String>>, String>>();
-	Ok(try!(passwords).into_iter().flat_map(|x| x).collect())
+	Ok(passwords?.into_iter().flat_map(|x| x).collect())
 }
 
 #[cfg(test)]

parity/main.rs

@@ -131,8 +131,8 @@ use dir::default_hypervisor_path;
 
 fn print_hash_of(maybe_file: Option<String>) -> Result<String, String> {
 	if let Some(file) = maybe_file {
-		let mut f = BufReader::new(try!(File::open(&file).map_err(|_| "Unable to open file".to_owned())));
-		let hash = try!(sha3(&mut f).map_err(|_| "Unable to read from file".to_owned()));
+		let mut f = BufReader::new(File::open(&file).map_err(|_| "Unable to open file".to_owned())?);
+		let hash = sha3(&mut f).map_err(|_| "Unable to read from file".to_owned())?;
 		Ok(hash.hex())
 	} else {
 		Err("Streaming from standard input not yet supported. Specify a file.".to_owned())
@@ -175,7 +175,7 @@ fn start(can_restart: bool) -> Result<PostExecutionAction, String> {
 		println!("{}", d);
 	}
 
-	let cmd = try!(conf.into_command());
+	let cmd = conf.into_command()?;
 	execute(cmd, can_restart)
 }
 

parity/migration.rs

@@ -104,7 +104,7 @@ fn current_version(path: &Path) -> Result<u32, Error> {
 		Err(_) => Err(Error::UnknownDatabaseVersion),
 		Ok(mut file) => {
 			let mut s = String::new();
-			try!(file.read_to_string(&mut s).map_err(|_| Error::UnknownDatabaseVersion));
+			file.read_to_string(&mut s).map_err(|_| Error::UnknownDatabaseVersion)?;
 			u32::from_str_radix(&s, 10).map_err(|_| Error::UnknownDatabaseVersion)
 		},
 	}
@@ -113,9 +113,9 @@ fn current_version(path: &Path) -> Result<u32, Error> {
 /// Writes current database version to the file.
 /// Creates a new file if the version file does not exist yet.
 fn update_version(path: &Path) -> Result<(), Error> {
-	try!(fs::create_dir_all(path));
-	let mut file = try!(File::create(version_file_path(path)));
-	try!(file.write_all(format!("{}", CURRENT_VERSION).as_bytes()));
+	fs::create_dir_all(path)?;
+	let mut file = File::create(version_file_path(path))?;
+	file.write_all(format!("{}", CURRENT_VERSION).as_bytes())?;
 	Ok(())
 }
 
@@ -145,7 +145,7 @@ pub fn default_migration_settings(compaction_profile: &CompactionProfile) -> Mig
 /// Migrations on the consolidated database.
 fn consolidated_database_migrations(compaction_profile: &CompactionProfile) -> Result<MigrationManager, Error> {
 	let mut manager = MigrationManager::new(default_migration_settings(compaction_profile));
-	try!(manager.add_migration(migrations::ToV10::new()).map_err(|_| Error::MigrationImpossible));
+	manager.add_migration(migrations::ToV10::new()).map_err(|_| Error::MigrationImpossible)?;
 	Ok(manager)
 }
 
@@ -171,16 +171,16 @@ fn consolidate_database(
 		wal: true,
 	};
 
-	let old_path_str = try!(old_db_path.to_str().ok_or(Error::MigrationImpossible));
-	let new_path_str = try!(new_db_path.to_str().ok_or(Error::MigrationImpossible));
+	let old_path_str = old_db_path.to_str().ok_or(Error::MigrationImpossible)?;
+	let new_path_str = new_db_path.to_str().ok_or(Error::MigrationImpossible)?;
 
-	let cur_db = Arc::new(try!(Database::open(&db_config, old_path_str).map_err(db_error)));
+	let cur_db = Arc::new(Database::open(&db_config, old_path_str).map_err(db_error)?);
 	// open new DB with proper number of columns
 	db_config.columns = migration.columns();
-	let mut new_db = try!(Database::open(&db_config, new_path_str).map_err(db_error));
+	let mut new_db = Database::open(&db_config, new_path_str).map_err(db_error)?;
 
 	// Migrate to new database (default column only)
-	try!(migration.migrate(cur_db, &config, &mut new_db, None));
+	migration.migrate(cur_db, &config, &mut new_db, None)?;
 
 	Ok(())
 }
@@ -198,20 +198,20 @@ fn migrate_database(version: u32, db_path: PathBuf, mut migrations: MigrationMan
 	let _ = fs::remove_dir_all(&backup_path);
 
 	// migrate old database to the new one
-	let temp_path = try!(migrations.execute(&db_path, version));
+	let temp_path = migrations.execute(&db_path, version)?;
 
 	// create backup
-	try!(fs::rename(&db_path, &backup_path));
+	fs::rename(&db_path, &backup_path)?;
 
 	// replace the old database with the new one
 	if let Err(err) = fs::rename(&temp_path, &db_path) {
 		// if something went wrong, bring back backup
-		try!(fs::rename(&backup_path, &db_path));
+		fs::rename(&backup_path, &db_path)?;
 		return Err(err.into());
 	}
 
 	// remove backup
-	try!(fs::remove_dir_all(&backup_path));
+	fs::remove_dir_all(&backup_path)?;
 
 	Ok(())
 }
@@ -223,7 +223,7 @@ fn exists(path: &Path) -> bool {
 /// Migrates the database.
 pub fn migrate(path: &Path, pruning: Algorithm, compaction_profile: CompactionProfile) -> Result<(), Error> {
 	// read version file.
-	let version = try!(current_version(path));
+	let version = current_version(path)?;
 
 	// migrate the databases.
 	// main db directory may already exists, so let's check if we have blocks dir
@@ -240,18 +240,18 @@ pub fn migrate(path: &Path, pruning: Algorithm, compaction_profile: CompactionPr
 	if version < CONSOLIDATION_VERSION && exists(&legacy::blocks_database_path(path)) {
 		println!("Migrating database from version {} to {}", version, CONSOLIDATION_VERSION);
 
-		try!(migrate_database(version, legacy::extras_database_path(path), try!(legacy::extras_database_migrations(&compaction_profile))));
-		try!(migrate_database(version, legacy::state_database_path(path), try!(legacy::state_database_migrations(pruning, &compaction_profile))));
-		try!(migrate_database(version, legacy::blocks_database_path(path), try!(legacy::blocks_database_migrations(&compaction_profile))));
+		migrate_database(version, legacy::extras_database_path(path), legacy::extras_database_migrations(&compaction_profile)?)?;
+		migrate_database(version, legacy::state_database_path(path), legacy::state_database_migrations(pruning, &compaction_profile)?)?;
+		migrate_database(version, legacy::blocks_database_path(path), legacy::blocks_database_migrations(&compaction_profile)?)?;
 
 		let db_path = consolidated_database_path(path);
 		// Remove the database dir (it shouldn't exist anyway, but it might when migration was interrupted)
 		let _ = fs::remove_dir_all(db_path.clone());
-		try!(consolidate_database(legacy::blocks_database_path(path), db_path.clone(), db::COL_HEADERS, Extract::Header, &compaction_profile));
-		try!(consolidate_database(legacy::blocks_database_path(path), db_path.clone(), db::COL_BODIES, Extract::Body, &compaction_profile));
-		try!(consolidate_database(legacy::extras_database_path(path), db_path.clone(), db::COL_EXTRA, Extract::All, &compaction_profile));
-		try!(consolidate_database(legacy::state_database_path(path), db_path.clone(), db::COL_STATE, Extract::All, &compaction_profile));
-		try!(consolidate_database(legacy::trace_database_path(path), db_path.clone(), db::COL_TRACE, Extract::All, &compaction_profile));
+		consolidate_database(legacy::blocks_database_path(path), db_path.clone(), db::COL_HEADERS, Extract::Header, &compaction_profile)?;
+		consolidate_database(legacy::blocks_database_path(path), db_path.clone(), db::COL_BODIES, Extract::Body, &compaction_profile)?;
+		consolidate_database(legacy::extras_database_path(path), db_path.clone(), db::COL_EXTRA, Extract::All, &compaction_profile)?;
+		consolidate_database(legacy::state_database_path(path), db_path.clone(), db::COL_STATE, Extract::All, &compaction_profile)?;
+		consolidate_database(legacy::trace_database_path(path), db_path.clone(), db::COL_TRACE, Extract::All, &compaction_profile)?;
 		let _ = fs::remove_dir_all(legacy::blocks_database_path(path));
 		let _ = fs::remove_dir_all(legacy::extras_database_path(path));
 		let _ = fs::remove_dir_all(legacy::state_database_path(path));
@@ -265,7 +265,7 @@ pub fn migrate(path: &Path, pruning: Algorithm, compaction_profile: CompactionPr
 	// Further migrations
 	if version >= CONSOLIDATION_VERSION && version < CURRENT_VERSION && exists(&consolidated_database_path(path)) {
 		println!("Migrating database from version {} to {}", ::std::cmp::max(CONSOLIDATION_VERSION, version), CURRENT_VERSION);
-		try!(migrate_database(version, consolidated_database_path(path), try!(consolidated_database_migrations(&compaction_profile))));
+		migrate_database(version, consolidated_database_path(path), consolidated_database_migrations(&compaction_profile)?)?;
 		println!("Migration finished");
 	}
 
@@ -313,14 +313,14 @@ mod legacy {
 	/// Migrations on the blocks database.
 	pub fn blocks_database_migrations(compaction_profile: &CompactionProfile) -> Result<MigrationManager, Error> {
 		let mut manager = MigrationManager::new(default_migration_settings(compaction_profile));
-		try!(manager.add_migration(migrations::blocks::V8::default()).map_err(|_| Error::MigrationImpossible));
+		manager.add_migration(migrations::blocks::V8::default()).map_err(|_| Error::MigrationImpossible)?;
 		Ok(manager)
 	}
 
 	/// Migrations on the extras database.
 	pub fn extras_database_migrations(compaction_profile: &CompactionProfile) -> Result<MigrationManager, Error> {
 		let mut manager = MigrationManager::new(default_migration_settings(compaction_profile));
-		try!(manager.add_migration(migrations::extras::ToV6).map_err(|_| Error::MigrationImpossible));
+		manager.add_migration(migrations::extras::ToV6).map_err(|_| Error::MigrationImpossible)?;
 		Ok(manager)
 	}
 
@@ -333,7 +333,7 @@ mod legacy {
 			_ => return Err(Error::UnsupportedPruningMethod),
 		};
 
-		try!(res.map_err(|_| Error::MigrationImpossible));
+		res.map_err(|_| Error::MigrationImpossible)?;
 		Ok(manager)
 	}
 }

parity/modules.rs

@@ -171,13 +171,13 @@ pub fn sync
 	)
 	-> Result<SyncModules, NetworkError>
 {
-	let eth_sync = try!(EthSync::new(Params {
+	let eth_sync = EthSync::new(Params {
 		config: sync_cfg, 
 		chain: client,
 		provider: provider,
 		snapshot_service: snapshot_service, 
 		network_config: net_cfg,
-	}));
+	})?;
 
 	Ok((eth_sync.clone() as Arc<SyncProvider>, eth_sync.clone() as Arc<ManageNetwork>, eth_sync.clone() as Arc<ChainNotify>))
 }

parity/params.rs

@@ -71,7 +71,7 @@ impl SpecType {
 			SpecType::Expanse => Ok(ethereum::new_expanse()),
 			SpecType::Dev => Ok(Spec::new_instant()),
 			SpecType::Custom(ref filename) => {
-				let file = try!(fs::File::open(filename).map_err(|_| "Could not load specification file."));
+				let file = fs::File::open(filename).map_err(|_| "Could not load specification file.")?;
 				Spec::load(file)
 			}
 		}

parity/presale.rs

@@ -31,15 +31,15 @@ pub struct ImportWallet {
 
 pub fn execute(cmd: ImportWallet) -> Result<String, String> {
 	let password: String = match cmd.password_file {
-		Some(file) => try!(password_from_file(file)),
-		None => try!(password_prompt()),
+		Some(file) => password_from_file(file)?,
+		None => password_prompt()?,
 	};
 
 	let dir = Box::new(DiskDirectory::create(cmd.path).unwrap());
 	let secret_store = Box::new(EthStore::open_with_iterations(dir, cmd.iterations).unwrap());
 	let acc_provider = AccountProvider::new(secret_store);
-	let wallet = try!(PresaleWallet::open(cmd.wallet_path).map_err(|_| "Unable to open presale wallet."));
-	let kp = try!(wallet.decrypt(&password).map_err(|_| "Invalid password."));
+	let wallet = PresaleWallet::open(cmd.wallet_path).map_err(|_| "Unable to open presale wallet.")?;
+	let kp = wallet.decrypt(&password).map_err(|_| "Invalid password.")?;
 	let address = acc_provider.insert_account(*kp.secret(), &password).unwrap();
 	Ok(format!("{:?}", address))
 }

parity/rpc.rs

@@ -89,8 +89,8 @@ pub fn new_http(conf: HttpConfiguration, deps: &Dependencies) -> Result<Option<H
 	}
 
 	let url = format!("{}:{}", conf.interface, conf.port);
-	let addr = try!(url.parse().map_err(|_| format!("Invalid JSONRPC listen host/port given: {}", url)));
-	Ok(Some(try!(setup_http_rpc_server(deps, &addr, conf.cors, conf.hosts, conf.apis))))
+	let addr = url.parse().map_err(|_| format!("Invalid JSONRPC listen host/port given: {}", url))?;
+	Ok(Some(setup_http_rpc_server(deps, &addr, conf.cors, conf.hosts, conf.apis)?))
 }
 
 fn setup_rpc_server(apis: ApiSet, deps: &Dependencies) -> Result<Server, String> {
@@ -105,7 +105,7 @@ pub fn setup_http_rpc_server(
 	allowed_hosts: Option<Vec<String>>,
 	apis: ApiSet
 ) -> Result<HttpServer, String> {
-	let server = try!(setup_rpc_server(apis, dependencies));
+	let server = setup_rpc_server(apis, dependencies)?;
 	let ph = dependencies.panic_handler.clone();
 	let start_result = server.start_http(url, cors_domains, allowed_hosts, ph);
 	match start_result {
@@ -120,11 +120,11 @@ pub fn setup_http_rpc_server(
 
 pub fn new_ipc(conf: IpcConfiguration, deps: &Dependencies) -> Result<Option<IpcServer>, String> {
 	if !conf.enabled { return Ok(None); }
-	Ok(Some(try!(setup_ipc_rpc_server(deps, &conf.socket_addr, conf.apis))))
+	Ok(Some(setup_ipc_rpc_server(deps, &conf.socket_addr, conf.apis)?))
 }
 
 pub fn setup_ipc_rpc_server(dependencies: &Dependencies, addr: &str, apis: ApiSet) -> Result<IpcServer, String> {
-	let server = try!(setup_rpc_server(apis, dependencies));
+	let server = setup_rpc_server(apis, dependencies)?;
 	match server.start_ipc(addr) {
 		Err(IpcServerError::Io(io_error)) => Err(format!("RPC io error: {}", io_error)),
 		Err(any_error) => Err(format!("Rpc error: {:?}", any_error)),

parity/run.rs

@@ -109,7 +109,7 @@ pub fn open_ui(dapps_conf: &dapps::Configuration, signer_conf: &signer::Configur
 		return Err("Cannot use UI command with UI turned off.".into())
 	}
 
-	let token = try!(signer::generate_token_and_url(signer_conf));
+	let token = signer::generate_token_and_url(signer_conf)?;
 	// Open a browser
 	url::open(&token.url);
 	// Print a message
@@ -133,7 +133,7 @@ pub fn execute(cmd: RunCmd, can_restart: bool, logger: Arc<RotatingLogger>) -> R
 	raise_fd_limit();
 
 	// load spec
-	let spec = try!(cmd.spec.spec());
+	let spec = cmd.spec.spec()?;
 
 	// load genesis hash
 	let genesis_hash = spec.genesis_header().hash();
@@ -145,19 +145,19 @@ pub fn execute(cmd: RunCmd, can_restart: bool, logger: Arc<RotatingLogger>) -> R
 	let user_defaults_path = db_dirs.user_defaults_path();
 
 	// load user defaults
-	let mut user_defaults = try!(UserDefaults::load(&user_defaults_path));
+	let mut user_defaults = UserDefaults::load(&user_defaults_path)?;
 
 	// select pruning algorithm
 	let algorithm = cmd.pruning.to_algorithm(&user_defaults);
 
 	// check if tracing is on
-	let tracing = try!(tracing_switch_to_bool(cmd.tracing, &user_defaults));
+	let tracing = tracing_switch_to_bool(cmd.tracing, &user_defaults)?;
 
 	// check if fatdb is on
-	let fat_db = try!(fatdb_switch_to_bool(cmd.fat_db, &user_defaults, algorithm));
+	let fat_db = fatdb_switch_to_bool(cmd.fat_db, &user_defaults, algorithm)?;
 
 	// get the mode
-	let mode = try!(mode_switch_to_bool(cmd.mode, &user_defaults));
+	let mode = mode_switch_to_bool(cmd.mode, &user_defaults)?;
 	trace!(target: "mode", "mode is {:?}", mode);
 	let network_enabled = match mode { Mode::Dark(_) | Mode::Off => false, _ => true, };
 
@@ -169,14 +169,14 @@ pub fn execute(cmd: RunCmd, can_restart: bool, logger: Arc<RotatingLogger>) -> R
 	let snapshot_path = db_dirs.snapshot_path();
 
 	// execute upgrades
-	try!(execute_upgrades(&cmd.dirs.base, &db_dirs, algorithm, cmd.compaction.compaction_profile(db_dirs.db_root_path().as_path())));
+	execute_upgrades(&cmd.dirs.base, &db_dirs, algorithm, cmd.compaction.compaction_profile(db_dirs.db_root_path().as_path()))?;
 
 	// create dirs used by parity
-	try!(cmd.dirs.create_dirs(cmd.dapps_conf.enabled, cmd.signer_conf.enabled));
+	cmd.dirs.create_dirs(cmd.dapps_conf.enabled, cmd.signer_conf.enabled)?;
 
 	// run in daemon mode
 	if let Some(pid_file) = cmd.daemon {
-		try!(daemonize(pid_file));
+		daemonize(pid_file)?;
 	}
 
 	// display info about used pruning algorithm
@@ -214,10 +214,10 @@ pub fn execute(cmd: RunCmd, can_restart: bool, logger: Arc<RotatingLogger>) -> R
 	sync_config.warp_sync = cmd.warp_sync;
 	sync_config.download_old_blocks = cmd.download_old_blocks;
 
-	let passwords = try!(passwords_from_files(&cmd.acc_conf.password_files));
+	let passwords = passwords_from_files(&cmd.acc_conf.password_files)?;
 
 	// prepare account provider
-	let account_provider = Arc::new(try!(prepare_account_provider(&cmd.dirs, &spec.data_dir, cmd.acc_conf, &passwords)));
+	let account_provider = Arc::new(prepare_account_provider(&cmd.dirs, &spec.data_dir, cmd.acc_conf, &passwords)?);
 
 	// let the Engine access the accounts
 	spec.engine.register_account_provider(account_provider.clone());
@@ -266,14 +266,14 @@ pub fn execute(cmd: RunCmd, can_restart: bool, logger: Arc<RotatingLogger>) -> R
 	let mut hypervisor = modules::hypervisor(&cmd.dirs.ipc_path());
 
 	// create client service.
-	let service = try!(ClientService::start(
+	let service = ClientService::start(
 		client_config,
 		&spec,
 		&client_path,
 		&snapshot_path,
 		&cmd.dirs.ipc_path(),
 		miner.clone(),
-	).map_err(|e| format!("Client service error: {:?}", e)));
+	).map_err(|e| format!("Client service error: {:?}", e))?;
 
 	// drop the spec to free up genesis state.
 	drop(spec);
@@ -289,7 +289,7 @@ pub fn execute(cmd: RunCmd, can_restart: bool, logger: Arc<RotatingLogger>) -> R
 	let external_miner = Arc::new(ExternalMiner::default());
 
 	// create sync object
-	let (sync_provider, manage_network, chain_notify) = try!(modules::sync(
+	let (sync_provider, manage_network, chain_notify) = modules::sync(
 		&mut hypervisor,
 		sync_config,
 		net_conf.into(),
@@ -297,7 +297,7 @@ pub fn execute(cmd: RunCmd, can_restart: bool, logger: Arc<RotatingLogger>) -> R
 		snapshot_service.clone(),
 		client.clone(),
 		&cmd.logger_config,
-	).map_err(|e| format!("Sync error: {}", e)));
+	).map_err(|e| format!("Sync error: {}", e))?;
 
 	service.add_notify(chain_notify.clone());
 
@@ -310,7 +310,7 @@ pub fn execute(cmd: RunCmd, can_restart: bool, logger: Arc<RotatingLogger>) -> R
 	let event_loop = EventLoop::spawn();
 
 	// fetch service
-	let fetch = try!(FetchClient::new().map_err(|e| format!("Error starting fetch client: {:?}", e)));
+	let fetch = FetchClient::new().map_err(|e| format!("Error starting fetch client: {:?}", e))?;
 
 	// the updater service
 	let updater = Updater::new(
@@ -359,8 +359,8 @@ pub fn execute(cmd: RunCmd, can_restart: bool, logger: Arc<RotatingLogger>) -> R
 	};
 
 	// start rpc servers
-	let http_server = try!(rpc::new_http(cmd.http_conf, &dependencies));
-	let ipc_server = try!(rpc::new_ipc(cmd.ipc_conf, &dependencies));
+	let http_server = rpc::new_http(cmd.http_conf, &dependencies)?;
+	let ipc_server = rpc::new_ipc(cmd.ipc_conf, &dependencies)?;
 
 	// the dapps server
 	let dapps_deps = dapps::Dependencies {
@@ -372,14 +372,14 @@ pub fn execute(cmd: RunCmd, can_restart: bool, logger: Arc<RotatingLogger>) -> R
 		fetch: fetch.clone(),
 		signer: deps_for_rpc_apis.signer_service.clone(),
 	};
-	let dapps_server = try!(dapps::new(cmd.dapps_conf.clone(), dapps_deps));
+	let dapps_server = dapps::new(cmd.dapps_conf.clone(), dapps_deps)?;
 
 	// the signer server
 	let signer_deps = signer::Dependencies {
 		panic_handler: panic_handler.clone(),
 		apis: deps_for_rpc_apis.clone(),
 	};
-	let signer_server = try!(signer::start(cmd.signer_conf.clone(), signer_deps));
+	let signer_server = signer::start(cmd.signer_conf.clone(), signer_deps)?;
 
 	// the informant
 	let informant = Arc::new(Informant::new(
@@ -397,7 +397,7 @@ pub fn execute(cmd: RunCmd, can_restart: bool, logger: Arc<RotatingLogger>) -> R
 	user_defaults.tracing = tracing;
 	user_defaults.fat_db = fat_db;
 	user_defaults.mode = mode;
-	try!(user_defaults.save(&user_defaults_path));
+	user_defaults.save(&user_defaults_path)?;
 
 	// tell client how to save the default mode if it gets changed.
 	client.on_mode_change(move |mode: &Mode| {
@@ -425,7 +425,7 @@ pub fn execute(cmd: RunCmd, can_restart: bool, logger: Arc<RotatingLogger>) -> R
 
 	// start ui
 	if cmd.ui {
-		try!(open_ui(&cmd.dapps_conf, &cmd.signer_conf));
+		open_ui(&cmd.dapps_conf, &cmd.signer_conf)?;
 	}
 
 	// Handle exit
@@ -477,9 +477,9 @@ fn prepare_account_provider(dirs: &Directories, data_dir: &str, cfg: AccountsCon
 
 	let path = dirs.keys_path(data_dir);
 	upgrade_key_location(&dirs.legacy_keys_path(cfg.testnet), &path);
-	let dir = Box::new(try!(DiskDirectory::create(&path).map_err(|e| format!("Could not open keys directory: {}", e))));
+	let dir = Box::new(DiskDirectory::create(&path).map_err(|e| format!("Could not open keys directory: {}", e))?);
 	let account_service = AccountProvider::new(Box::new(
-		try!(EthStore::open_with_iterations(dir, cfg.iterations).map_err(|e| format!("Could not open keys directory: {}", e)))
+		EthStore::open_with_iterations(dir, cfg.iterations).map_err(|e| format!("Could not open keys directory: {}", e))?
 	));
 
 	for a in cfg.unlocked_accounts {

parity/signer.rs

@@ -65,7 +65,7 @@ pub fn start(conf: Configuration, deps: Dependencies) -> Result<Option<SignerSer
 	if !conf.enabled {
 		Ok(None)
 	} else {
-		Ok(Some(try!(do_start(conf, deps))))
+		Ok(Some(do_start(conf, deps)?))
 	}
 }
 
@@ -77,11 +77,11 @@ fn codes_path(path: String) -> PathBuf {
 }
 
 pub fn execute(cmd: Configuration) -> Result<String, String> {
-	Ok(try!(generate_token_and_url(&cmd)).message)
+	Ok(generate_token_and_url(&cmd)?.message)
 }
 
 pub fn generate_token_and_url(conf: &Configuration) -> Result<NewToken, String> {
-	let code = try!(generate_new_token(conf.signer_path.clone()).map_err(|err| format!("Error generating token: {:?}", err)));
+	let code = generate_new_token(conf.signer_path.clone()).map_err(|err| format!("Error generating token: {:?}", err))?;
 	let auth_url = format!("http://{}:{}/#/auth?token={}", conf.interface, conf.port, code);
 	// And print in to the console
 	Ok(NewToken {
@@ -101,18 +101,18 @@ Or use the generated token:
 
 pub fn generate_new_token(path: String) -> io::Result<String> {
 	let path = codes_path(path);
-	let mut codes = try!(signer::AuthCodes::from_file(&path));
+	let mut codes = signer::AuthCodes::from_file(&path)?;
 	codes.clear_garbage();
-	let code = try!(codes.generate_new());
-	try!(codes.to_file(&path));
+	let code = codes.generate_new()?;
+	codes.to_file(&path)?;
 	trace!("New key code created: {}", Colour::White.bold().paint(&code[..]));
 	Ok(code)
 }
 
 fn do_start(conf: Configuration, deps: Dependencies) -> Result<SignerServer, String> {
-	let addr = try!(format!("{}:{}", conf.interface, conf.port)
+	let addr = format!("{}:{}", conf.interface, conf.port)
 		.parse()
-		.map_err(|_| format!("Invalid port specified: {}", conf.port)));
+		.map_err(|_| format!("Invalid port specified: {}", conf.port))?;
 
 	let start_result = {
 		let server = signer::ServerBuilder::new(