Reorg the transaction module

 - split the transaction module to legacy/eip2930/eip1559 modules
 - add to_message method for LegacyTransaction/EIP2930Transaction/EIP1559Transaction
 - adjust some imports

src/block.rs

@@ -1,12 +1,17 @@
-use crate::{
-	util::ordered_trie_root, EnvelopedDecodable, EnvelopedEncodable, Header, PartialHeader,
-	TransactionAny, TransactionV0, TransactionV1, TransactionV2,
-};
+#[cfg(not(feature = "std"))]
 use alloc::vec::Vec;
+
 use ethereum_types::H256;
-use rlp::{Decodable, DecoderError, Encodable, Rlp, RlpStream};
+use rlp::{DecoderError, Rlp, RlpStream};
 use sha3::{Digest, Keccak256};
 
+use crate::{
+	enveloped::{EnvelopedDecodable, EnvelopedEncodable},
+	header::{Header, PartialHeader},
+	transaction::{TransactionAny, TransactionV0, TransactionV1, TransactionV2},
+	util::ordered_trie_root,
+};
+
 #[derive(Clone, Debug, PartialEq, Eq)]
 #[cfg_attr(
 	feature = "with-codec",
@@ -19,7 +24,7 @@ pub struct Block<T> {
 	pub ommers: Vec<Header>,
 }
 
-impl<T: EnvelopedEncodable> Encodable for Block<T> {
+impl<T: EnvelopedEncodable> rlp::Encodable for Block<T> {
 	fn rlp_append(&self, s: &mut RlpStream) {
 		s.begin_list(3);
 		s.append(&self.header);
@@ -34,7 +39,7 @@ impl<T: EnvelopedEncodable> Encodable for Block<T> {
 	}
 }
 
-impl<T: EnvelopedDecodable> Decodable for Block<T> {
+impl<T: EnvelopedDecodable> rlp::Decodable for Block<T> {
 	fn decode(rlp: &Rlp) -> Result<Self, DecoderError> {
 		Ok(Self {
 			header: rlp.val_at(0)?,

src/lib.rs

@@ -1,5 +1,6 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
+#[cfg(not(feature = "std"))]
 extern crate alloc;
 
 mod account;
@@ -12,12 +13,15 @@ mod transaction;
 pub mod util;
 
 // Alias for `Vec<u8>`. This type alias is necessary for rlp-derive to work correctly.
+#[cfg(not(feature = "std"))]
 type Bytes = alloc::vec::Vec<u8>;
+#[cfg(feature = "std")]
+type Bytes = Vec<u8>;
 
-pub use account::Account;
-pub use block::*;
-pub use enveloped::*;
-pub use header::{Header, PartialHeader};
-pub use log::Log;
-pub use receipt::*;
-pub use transaction::*;
+pub use crate::account::Account;
+pub use crate::block::*;
+pub use crate::enveloped::*;
+pub use crate::header::{Header, PartialHeader};
+pub use crate::log::Log;
+pub use crate::receipt::*;
+pub use crate::transaction::*;

src/log.rs

@@ -1,7 +1,10 @@
-use crate::Bytes;
+#[cfg(not(feature = "std"))]
 use alloc::vec::Vec;
+
 use ethereum_types::{H160, H256};
 
+use crate::Bytes;
+
 #[derive(Clone, Debug, PartialEq, Eq)]
 #[derive(rlp::RlpEncodable, rlp::RlpDecodable)]
 #[cfg_attr(

src/receipt.rs

@@ -1,9 +1,15 @@
-use crate::{EnvelopedDecodable, EnvelopedDecoderError, EnvelopedEncodable, Log};
+#[cfg(not(feature = "std"))]
 use alloc::vec::Vec;
+
 use bytes::BytesMut;
 use ethereum_types::{Bloom, H256, U256};
 use rlp::{Decodable, DecoderError, Rlp};
 
+use crate::{
+	enveloped::{EnvelopedDecodable, EnvelopedDecoderError, EnvelopedEncodable},
+	log::Log,
+};
+
 #[derive(Clone, Debug, PartialEq, Eq)]
 #[derive(rlp::RlpEncodable, rlp::RlpDecodable)]
 #[cfg_attr(