Add AsRef and AsMut for AccountId20 (polkadot-evm#1139)

* Update toolchain toml config

* Add helper functions

Author: boundless-forest

primitives/account/src/lib.rs

@@ -84,6 +84,19 @@ impl From<[u8; 20]> for AccountId20 {
 	}
 }
 
+impl<'a> TryFrom<&'a [u8]> for AccountId20 {
+	type Error = ();
+	fn try_from(x: &'a [u8]) -> Result<AccountId20, ()> {
+		if x.len() == 20 {
+			let mut data = [0; 20];
+			data.copy_from_slice(x);
+			Ok(AccountId20(data))
+		} else {
+			Err(())
+		}
+	}
+}
+
 impl From<AccountId20> for [u8; 20] {
 	fn from(val: AccountId20) -> Self {
 		val.0
@@ -102,6 +115,30 @@ impl From<AccountId20> for H160 {
 	}
 }
 
+impl AsRef<[u8]> for AccountId20 {
+	fn as_ref(&self) -> &[u8] {
+		&self.0[..]
+	}
+}
+
+impl AsMut<[u8]> for AccountId20 {
+	fn as_mut(&mut self) -> &mut [u8] {
+		&mut self.0[..]
+	}
+}
+
+impl AsRef<[u8; 20]> for AccountId20 {
+	fn as_ref(&self) -> &[u8; 20] {
+		&self.0
+	}
+}
+
+impl AsMut<[u8; 20]> for AccountId20 {
+	fn as_mut(&mut self) -> &mut [u8; 20] {
+		&mut self.0
+	}
+}
+
 impl From<ecdsa::Public> for AccountId20 {
 	fn from(pk: ecdsa::Public) -> Self {
 		let decompressed = libsecp256k1::PublicKey::parse_compressed(&pk.0)

rust-toolchain.toml

@@ -1,8 +1,5 @@
 [toolchain]
-# Stable
-#channel = "1.70.0" # rustc 1.70.0 (84c898d65 2023-05-13)
-# Nightly
-channel = "nightly-2023-05-23" # rustc 1.71.0-nightly (8b4b20836 2023-05-22)
-components = ["rustfmt", "clippy"]
-targets = ["wasm32-unknown-unknown"]
-profile = "minimal"
+channel    = "nightly-2023-05-22"
+components = ["cargo", "clippy", "rustc", "rustfmt", "rust-src"]
+profile    = "minimal"
+targets    = ["wasm32-unknown-unknown"]