Expunge error-chain (feat. tomaka) (#2662)

* Remove error_chain

* Expunge error-chain from rpc and service.

* Expunge from transaction pool.

* Expunge from node/cli

* Expunge from keystore.

* Remove some boilerplate.

* Fix remaining stuff.

* Improve on deprecation message.

* Fix issues.

* Fix trnsaction pool tests.

* Fix the rest.

* Fix borked merge.

* Update lock

substrate/core/cli/src/error.rs

@@ -16,26 +16,38 @@
 
 //! Initialization errors.
 
-// Silence: `use of deprecated item 'std::error::Error::cause': replaced by Error::source, which can support downcasting`
-// https://github.com/paritytech/substrate/issues/1547
-#![allow(deprecated)]
-
 use client;
-use error_chain::{error_chain, error_chain_processing, impl_error_chain_processed,
-	impl_extract_backtrace, impl_error_chain_kind};
 
-error_chain! {
-	foreign_links {
-		Io(::std::io::Error) #[doc="IO error"];
-		Cli(::clap::Error) #[doc="CLI error"];
-		Service(::service::Error) #[doc="Substrate service error"];
-		Client(client::error::Error) #[doc="Client error"];
-	}
-	errors {
-		/// Input error.
-		Input(m: String) {
-			description("Invalid input"),
-			display("{}", m),
+/// Result type alias for the CLI.
+pub type Result<T> = std::result::Result<T, Error>;
+
+/// Error type for the CLI.
+#[derive(Debug, derive_more::Display, derive_more::From)]
+pub enum Error {
+	/// Io error
+	Io(std::io::Error),
+	/// Cli error
+	Cli(clap::Error),
+	/// Service error
+	Service(service::Error),
+	/// Client error
+	Client(client::error::Error),
+	/// Input error
+	Input(String),
+	/// Invalid listen multiaddress
+	#[display(fmt="Invalid listen multiaddress")]
+	InvalidListenMultiaddress
+}
+
+impl std::error::Error for Error {
+	fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+		match self {
+			Error::Io(ref err) => Some(err),
+			Error::Cli(ref err) => Some(err),
+			Error::Service(ref err) => Some(err),
+			Error::Client(ref err) => Some(err),
+			Error::Input(_) => None,
+			Error::InvalidListenMultiaddress => None,
 		}
 	}
 }