Fix warnings and add -D warnings check in CI

- Eliminates dead code left over from #205
- Adds `-D warnings` in CI so that warnings are treated as errors.
  This ensures code must be warning-free to pass CI.

.github/workflows/rust.yml

@@ -8,6 +8,7 @@ on:
 
 env:
   CARGO_TERM_COLOR: always
+  RUSTFLAGS: '-D warnings'
 
 jobs:
   test:

src/errors.rs

@@ -36,11 +36,6 @@ pub(crate) enum InternalError {
     },
     /// The verification equation wasn't satisfied
     VerifyError,
-    /// Two arrays did not match in size, making the called signature
-    /// verification method impossible.
-    ArrayLengthError{ name_a: &'static str, length_a: usize,
-                      name_b: &'static str, length_b: usize,
-                      name_c: &'static str, length_c: usize, },
     /// An ed25519ph signature can only take up to 255 octets of context.
     PrehashedContextLengthError,
     /// A mismatched (public, secret) key pair.
@@ -58,11 +53,6 @@ impl Display for InternalError {
                 => write!(f, "{} must be {} bytes in length", n, l),
             InternalError::VerifyError
                 => write!(f, "Verification equation was not satisfied"),
-            InternalError::ArrayLengthError{ name_a: na, length_a: la,
-                                             name_b: nb, length_b: lb,
-                                             name_c: nc, length_c: lc, }
-                => write!(f, "Arrays must be the same length: {} has length {},
-                              {} has length {}, {} has length {}.", na, la, nb, lb, nc, lc),
             InternalError::PrehashedContextLengthError
                 => write!(f, "An ed25519ph signature can only take up to 255 octets of context"),
             InternalError::MismatchedKeypairError => write!(f, "Mismatched Keypair detected"),

src/secret.rs

@@ -292,109 +292,6 @@ impl<'a> From<&'a SecretKey> for ExpandedSecretKey {
 }
 
 impl ExpandedSecretKey {
-    /// Convert this `ExpandedSecretKey` into an array of 64 bytes.
-    ///
-    /// # Returns
-    ///
-    /// An array of 64 bytes.  The first 32 bytes represent the "expanded"
-    /// secret key, and the last 32 bytes represent the "domain-separation"
-    /// "nonce".
-    ///
-    /// # Examples
-    ///
-    /// ```ignore
-    /// # extern crate rand;
-    /// # extern crate sha2;
-    /// # extern crate ed25519_dalek;
-    /// #
-    /// # #[cfg(feature = "std")]
-    /// # fn main() {
-    /// #
-    /// use rand::rngs::OsRng;
-    /// use ed25519_dalek::{SecretKey, ExpandedSecretKey};
-    ///
-    /// let mut csprng = OsRng{};
-    /// let secret_key: SecretKey = SecretKey::generate(&mut csprng);
-    /// let expanded_secret_key: ExpandedSecretKey = ExpandedSecretKey::from(&secret_key);
-    /// let expanded_secret_key_bytes: [u8; 64] = expanded_secret_key.to_bytes();
-    ///
-    /// assert!(&expanded_secret_key_bytes[..] != &[0u8; 64][..]);
-    /// # }
-    /// #
-    /// # #[cfg(not(feature = "std"))]
-    /// # fn main() { }
-    /// ```
-    #[inline]
-    pub fn to_bytes(&self) -> [u8; EXPANDED_SECRET_KEY_LENGTH] {
-        let mut bytes: [u8; 64] = [0u8; 64];
-
-        bytes[..32].copy_from_slice(self.key.as_bytes());
-        bytes[32..].copy_from_slice(&self.nonce[..]);
-        bytes
-    }
-
-    /// Construct an `ExpandedSecretKey` from a slice of bytes.
-    ///
-    /// # Returns
-    ///
-    /// A `Result` whose okay value is an EdDSA `ExpandedSecretKey` or whose
-    /// error value is an `SignatureError` describing the error that occurred.
-    ///
-    /// # Examples
-    ///
-    /// ```ignore
-    /// # extern crate rand;
-    /// # extern crate sha2;
-    /// # extern crate ed25519_dalek;
-    /// #
-    /// # use ed25519_dalek::{ExpandedSecretKey, SignatureError};
-    /// #
-    /// # #[cfg(feature = "std")]
-    /// # fn do_test() -> Result<ExpandedSecretKey, SignatureError> {
-    /// #
-    /// use rand::rngs::OsRng;
-    /// use ed25519_dalek::{SecretKey, ExpandedSecretKey};
-    /// use ed25519_dalek::SignatureError;
-    ///
-    /// let mut csprng = OsRng{};
-    /// let secret_key: SecretKey = SecretKey::generate(&mut csprng);
-    /// let expanded_secret_key: ExpandedSecretKey = ExpandedSecretKey::from(&secret_key);
-    /// let bytes: [u8; 64] = expanded_secret_key.to_bytes();
-    /// let expanded_secret_key_again = ExpandedSecretKey::from_bytes(&bytes)?;
-    /// #
-    /// # Ok(expanded_secret_key_again)
-    /// # }
-    /// #
-    /// # #[cfg(feature = "std")]
-    /// # fn main() {
-    /// #     let result = do_test();
-    /// #     assert!(result.is_ok());
-    /// # }
-    /// #
-    /// # #[cfg(not(feature = "std"))]
-    /// # fn main() { }
-    /// ```
-    #[inline]
-    pub(crate) fn from_bytes(bytes: &[u8]) -> Result<ExpandedSecretKey, SignatureError> {
-        if bytes.len() != EXPANDED_SECRET_KEY_LENGTH {
-            return Err(InternalError::BytesLengthError {
-                name: "ExpandedSecretKey",
-                length: EXPANDED_SECRET_KEY_LENGTH,
-            }
-            .into());
-        }
-        let mut lower: [u8; 32] = [0u8; 32];
-        let mut upper: [u8; 32] = [0u8; 32];
-
-        lower.copy_from_slice(&bytes[00..32]);
-        upper.copy_from_slice(&bytes[32..64]);
-
-        Ok(ExpandedSecretKey {
-            key: Scalar::from_bits(lower),
-            nonce: upper,
-        })
-    }
-
     /// Sign a message with this `ExpandedSecretKey`.
     #[allow(non_snake_case)]
     pub(crate) fn sign(&self, message: &[u8], public_key: &PublicKey) -> ed25519::Signature {

tests/ed25519.rs

@@ -285,9 +285,9 @@ mod integrations {
     }
 }
 
-#[serde(crate = "serde_crate")]
 #[cfg(all(test, feature = "serde"))]
 #[derive(Debug, serde_crate::Serialize, serde_crate::Deserialize)]
+#[serde(crate = "serde_crate")]
 struct Demo {
     keypair: Keypair
 }
@@ -296,8 +296,6 @@ struct Demo {
 mod serialisation {
     use super::*;
 
-    use ed25519::signature::Signature as _;
-
     // The size for bincode to serialize the length of a byte array.
     static BINCODE_INT_LENGTH: usize = 8;