diff --git a/substrate/client/transaction-pool/graph/src/error.rs b/substrate/client/transaction-pool/graph/src/error.rs
deleted file mode 100644
index 01fcb9f8dc..0000000000
--- a/substrate/client/transaction-pool/graph/src/error.rs
+++ /dev/null
@@ -1,81 +0,0 @@
-// This file is part of Substrate.
-
-// Copyright (C) 2018-2020 Parity Technologies (UK) Ltd.
-// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
-
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License
-// along with this program. If not, see <https://www.gnu.org/licenses/>.
-
-//! Transaction pool errors.
-
-use sp_runtime::transaction_validity::{
-	TransactionPriority as Priority, InvalidTransaction, UnknownTransaction,
-};
-
-/// Transaction pool result.
-pub type Result<T> = std::result::Result<T, Error>;
-
-/// Transaction pool error type.
-#[derive(Debug, thiserror::Error, derive_more::From)]
-#[allow(missing_docs)]
-pub enum Error {
-	/// Transaction is not verifiable yet, but might be in the future.
-	#[error("Unknown transaction validity: {0:?}")]
-	UnknownTransaction(UnknownTransaction),
-
-	#[error("Invalid transaction validity: {0:?}")]
-	InvalidTransaction(InvalidTransaction),
-	/// The transaction validity returned no "provides" tag.
-	///
-	/// Such transactions are not accepted to the pool, since we use those tags
-	/// to define identity of transactions (occupance of the same "slot").
-	#[error("The transaction validity returned no `provides` tags, so the pool can't identify it.")]
-	NoTagsProvided,
-
-	#[error("Temporarily Banned")]
-	TemporarilyBanned,
-
-	#[error("[{0:?}] Transaction is already in the pool")]
-	AlreadyImported(Box<dyn std::any::Any + Send>),
-
-	#[error("Transaction cannot be imported due to too low priority ({0} > {1})", old, new)]
-	TooLowPriority {
-		/// Transaction already in the pool.
-		old: Priority,
-		/// Transaction entering the pool.
-		new: Priority
-	},
-
-	#[error("Dependency cycle detected")]
-	CycleDetected,
-
-	#[error("Transaction couldn't enter the pool because of the limit.")]
-	ImmediatelyDropped,
-
-	#[error("Invlaid block id: {0}")]
-	InvalidBlockId(String),
-}
-
-/// Transaction pool error conversion.
-pub trait IntoPoolError: ::std::error::Error + Send + Sized {
-	/// Try to extract original `Error`
-	///
-	/// This implementation is optional and used only to
-	/// provide more descriptive error messages for end users
-	/// of RPC API.
-	fn into_pool_error(self) -> ::std::result::Result<Error, Self> { Err(self) }
-}
-
-impl IntoPoolError for Error {
-	fn into_pool_error(self) -> ::std::result::Result<Error, Self> { Ok(self) }
-}