crypto: key: Move error code to the bottom of the file

Error code is boring, put it at the bottom of the file.

Refactor only, no logic changes.

bitcoin/src/crypto/key.rs

@@ -23,63 +23,6 @@ use crate::prelude::*;
 use crate::taproot::{TapNodeHash, TapTweakHash};
 use crate::{base58, io};
 
-/// A key-related error.
-#[derive(Debug, Clone, PartialEq, Eq)]
-#[non_exhaustive]
-pub enum Error {
-    /// Base58 encoding error
-    Base58(base58::Error),
-    /// secp256k1-related error
-    Secp256k1(secp256k1::Error),
-    /// Invalid key prefix error
-    InvalidKeyPrefix(u8),
-    /// Hex decoding error
-    Hex(hex::HexToArrayError),
-    /// `PublicKey` hex should be 66 or 130 digits long.
-    InvalidHexLength(usize),
-}
-
-impl fmt::Display for Error {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        use Error::*;
-
-        match *self {
-            Base58(ref e) => write_err!(f, "key base58 error"; e),
-            Secp256k1(ref e) => write_err!(f, "key secp256k1 error"; e),
-            InvalidKeyPrefix(ref b) => write!(f, "key prefix invalid: {}", b),
-            Hex(ref e) => write_err!(f, "key hex decoding error"; e),
-            InvalidHexLength(got) =>
-                write!(f, "pubkey hex should be 66 or 130 digits long, got: {}", got),
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-impl std::error::Error for Error {
-    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
-        use self::Error::*;
-
-        match self {
-            Base58(e) => Some(e),
-            Secp256k1(e) => Some(e),
-            Hex(e) => Some(e),
-            InvalidKeyPrefix(_) | InvalidHexLength(_) => None,
-        }
-    }
-}
-
-impl From<base58::Error> for Error {
-    fn from(e: base58::Error) -> Error { Error::Base58(e) }
-}
-
-impl From<secp256k1::Error> for Error {
-    fn from(e: secp256k1::Error) -> Error { Error::Secp256k1(e) }
-}
-
-impl From<hex::HexToArrayError> for Error {
-    fn from(e: hex::HexToArrayError) -> Self { Error::Hex(e) }
-}
-
 /// A Bitcoin ECDSA public key
 #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct PublicKey {
@@ -732,6 +675,62 @@ impl From<TweakedKeyPair> for TweakedPublicKey {
     #[inline]
     fn from(pair: TweakedKeyPair) -> Self { TweakedPublicKey::from_keypair(pair) }
 }
+/// A key-related error.
+#[derive(Debug, Clone, PartialEq, Eq)]
+#[non_exhaustive]
+pub enum Error {
+    /// Base58 encoding error
+    Base58(base58::Error),
+    /// secp256k1-related error
+    Secp256k1(secp256k1::Error),
+    /// Invalid key prefix error
+    InvalidKeyPrefix(u8),
+    /// Hex decoding error
+    Hex(hex::HexToArrayError),
+    /// `PublicKey` hex should be 66 or 130 digits long.
+    InvalidHexLength(usize),
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use Error::*;
+
+        match *self {
+            Base58(ref e) => write_err!(f, "key base58 error"; e),
+            Secp256k1(ref e) => write_err!(f, "key secp256k1 error"; e),
+            InvalidKeyPrefix(ref b) => write!(f, "key prefix invalid: {}", b),
+            Hex(ref e) => write_err!(f, "key hex decoding error"; e),
+            InvalidHexLength(got) =>
+                write!(f, "pubkey hex should be 66 or 130 digits long, got: {}", got),
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for Error {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        use self::Error::*;
+
+        match self {
+            Base58(e) => Some(e),
+            Secp256k1(e) => Some(e),
+            Hex(e) => Some(e),
+            InvalidKeyPrefix(_) | InvalidHexLength(_) => None,
+        }
+    }
+}
+
+impl From<base58::Error> for Error {
+    fn from(e: base58::Error) -> Error { Error::Base58(e) }
+}
+
+impl From<secp256k1::Error> for Error {
+    fn from(e: secp256k1::Error) -> Error { Error::Secp256k1(e) }
+}
+
+impl From<hex::HexToArrayError> for Error {
+    fn from(e: hex::HexToArrayError) -> Self { Error::Hex(e) }
+}
 
 #[cfg(test)]
 mod tests {