Remove must_use spam

crypto/dalek-ff-group/src/field.rs

@@ -217,7 +217,6 @@ impl PrimeFieldBits for FieldElement {
 
 impl FieldElement {
   /// Interpret the value as a little-endian integer, square it, and reduce it into a FieldElement.
-  #[must_use]
   pub fn from_square(value: [u8; 32]) -> Self {
     let value = U256::from_le_bytes(value);
     Self(reduce(U512::from(value.mul_wide(&value))))
@@ -259,7 +258,6 @@ impl FieldElement {
   /// The result is only a valid square root if the Choice is true.
   /// RFC 8032 simply fails if there isn't a square root, leaving any return value undefined.
   /// Ristretto explicitly returns 0 or sqrt((SQRT_M1 * u) / v).
-  #[must_use]
   pub fn sqrt_ratio_i(u: Self, v: Self) -> (Choice, Self) {
     let i = SQRT_M1;
 

crypto/dalek-ff-group/src/lib.rs

@@ -223,13 +223,11 @@ impl Scalar {
   }
 
   /// Perform wide reduction on a 64-byte array to create a Scalar without bias.
-  #[must_use]
   pub fn from_bytes_mod_order_wide(bytes: &[u8; 64]) -> Self {
     Self(DScalar::from_bytes_mod_order_wide(bytes))
   }
 
   /// Derive a Scalar without bias from a digest via wide reduction.
-  #[must_use]
   pub fn from_hash<D: Digest<OutputSize = U64> + HashMarker>(hash: D) -> Self {
     let mut output = [0u8; 64];
     output.copy_from_slice(&hash.finalize());

crypto/dkg/src/frost.rs

@@ -94,7 +94,6 @@ impl<C: Ciphersuite> KeyGenMachine<C> {
   /// Create a new machine to generate a key.
   ///
   /// The context string should be unique among multisigs.
-  #[must_use]
   pub const fn new(params: ThresholdParams, context: String) -> Self {
     Self { params, context, curve: PhantomData }
   }

crypto/dkg/src/lib.rs

@@ -33,7 +33,6 @@ pub mod tests;
 pub struct Participant(pub(crate) u16);
 impl Participant {
   /// Create a new Participant identifier from a u16.
-  #[must_use]
   pub const fn new(i: u16) -> Option<Self> {
     if i == 0 {
       None
@@ -44,7 +43,6 @@ impl Participant {
 
   /// Convert a Participant identifier to bytes.
   #[allow(clippy::wrong_self_convention)]
-  #[must_use]
   pub const fn to_bytes(&self) -> [u8; 2] {
     self.0.to_le_bytes()
   }
@@ -183,24 +181,20 @@ mod lib {
     }
 
     /// Return the threshold for a multisig with these parameters.
-    #[must_use]
     pub const fn t(&self) -> u16 {
       self.t
     }
     /// Return the amount of participants for a multisig with these parameters.
-    #[must_use]
     pub const fn n(&self) -> u16 {
       self.n
     }
     /// Return the participant index of the share with these parameters.
-    #[must_use]
     pub const fn i(&self) -> Participant {
       self.i
     }
   }
 
   /// Calculate the lagrange coefficient for a signing set.
-  #[must_use]
   pub fn lagrange<F: PrimeField>(i: Participant, included: &[Participant]) -> F {
     let i_f = F::from(u64::from(u16::from(i)));
 
@@ -259,7 +253,6 @@ mod lib {
   }
 
   impl<C: Ciphersuite> ThresholdCore<C> {
-    #[must_use]
     pub(crate) fn new(
       params: ThresholdParams,
       secret_share: Zeroizing<C::F>,
@@ -420,7 +413,6 @@ mod lib {
 
   impl<C: Ciphersuite> ThresholdKeys<C> {
     /// Create a new set of ThresholdKeys from a ThresholdCore.
-    #[must_use]
     pub fn new(core: ThresholdCore<C>) -> Self {
       Self { core: Arc::new(core), offset: None }
     }

crypto/ed448/src/scalar.rs

@@ -53,7 +53,6 @@ field!(
 
 impl Scalar {
   /// Perform a wide reduction to obtain a non-biased Scalar.
-  #[must_use]
   pub fn wide_reduce(bytes: [u8; 114]) -> Self {
     let wide = U1024::from_le_slice(&[bytes.as_ref(), &[0; 14]].concat());
     Self(Residue::new(&U448::from_le_slice(

crypto/frost/src/algorithm.rs

@@ -147,7 +147,6 @@ pub type IetfSchnorr<C, H> = Schnorr<C, IetfTranscript, H>;
 
 impl<C: Curve, T: Sync + Clone + Debug + Transcript, H: Hram<C>> Schnorr<C, T, H> {
   /// Construct a Schnorr algorithm continuing the specified transcript.
-  #[must_use]
   pub const fn new(transcript: T) -> Self {
     Self { transcript, c: None, _hram: PhantomData }
   }
@@ -157,7 +156,6 @@ impl<C: Curve, H: Hram<C>> IetfSchnorr<C, H> {
   /// Construct a IETF-compatible Schnorr algorithm.
   ///
   /// Please see the `IetfSchnorr` documentation for the full details of this.
-  #[must_use]
   pub const fn ietf() -> Self {
     Self::new(IetfTranscript(vec![]))
   }

crypto/frost/src/curve/mod.rs

@@ -46,7 +46,6 @@ pub trait Curve: Ciphersuite {
   const CONTEXT: &'static [u8];
 
   /// Hash the given dst and data to a byte vector. Used to instantiate H4 and H5.
-  #[must_use]
   fn hash(dst: &[u8], data: &[u8]) -> Output<Self::H> {
     Self::H::digest([Self::CONTEXT, dst, data].concat())
   }
@@ -54,31 +53,26 @@ pub trait Curve: Ciphersuite {
   /// Field element from hash. Used during key gen and by other crates under Serai as a general
   /// utility. Used to instantiate H1 and H3.
   #[allow(non_snake_case)]
-  #[must_use]
   fn hash_to_F(dst: &[u8], msg: &[u8]) -> Self::F {
     <Self as Ciphersuite>::hash_to_F(&[Self::CONTEXT, dst].concat(), msg)
   }
 
   /// Hash the message for the binding factor. H4 from the IETF draft.
-  #[must_use]
   fn hash_msg(msg: &[u8]) -> Output<Self::H> {
     Self::hash(b"msg", msg)
   }
 
   /// Hash the commitments for the binding factor. H5 from the IETF draft.
-  #[must_use]
   fn hash_commitments(commitments: &[u8]) -> Output<Self::H> {
     Self::hash(b"com", commitments)
   }
 
   /// Hash the commitments and message to calculate the binding factor. H1 from the IETF draft.
-  #[must_use]
   fn hash_binding_factor(binding: &[u8]) -> Self::F {
     <Self as Curve>::hash_to_F(b"rho", binding)
   }
 
   /// Securely generate a random nonce. H3 from the IETF draft.
-  #[must_use]
   fn random_nonce<R: RngCore + CryptoRng>(
     secret: &Zeroizing<Self::F>,
     rng: &mut R,

crypto/multiexp/src/batch.rs

@@ -37,7 +37,6 @@ where
   /// Create a new batch verifier, expected to verify the following amount of statements.
   ///
   /// `capacity` is a size hint and is not required to be accurate.
-  #[must_use]
   pub fn new(capacity: usize) -> Self {
     Self(Zeroizing::new(Vec::with_capacity(capacity)))
   }
@@ -112,7 +111,6 @@ where
   ///
   /// This function will only return the ID of one invalid statement, even if multiple are invalid.
   // A constant time variant may be beneficial for robust protocols
-  #[must_use]
   pub fn blame_vartime(&self) -> Option<Id> {
     let mut slice = self.0.as_slice();
     while slice.len() > 1 {

crypto/schnorr/src/aggregate.rs

@@ -155,7 +155,6 @@ impl<C: Ciphersuite> SchnorrAggregator<C> {
   ///
   /// The DST used here must prevent a collision with whatever hash function produced the
   /// challenges.
-  #[must_use]
   pub fn new(dst: &'static [u8]) -> Self {
     let mut res = Self { digest: DigestTranscript::<C::H>::new(dst), sigs: vec![] };
     res.digest.domain_separate(b"signatures");

crypto/schnorrkel/src/lib.rs

@@ -62,7 +62,6 @@ impl Schnorrkel {
   /// Create a new algorithm with the specified context.
   ///
   /// If the context is greater than or equal to 4 GB in size, this will panic.
-  #[must_use]
   pub fn new(context: &'static [u8]) -> Self {
     Self { context, schnorr: Schnorr::new(MerlinTranscript::new(b"FROST Schnorrkel")), msg: None }
   }

crypto/transcript/src/lib.rs

@@ -103,7 +103,6 @@ impl<D: Send + Clone + SecureDigest> DigestTranscript<D> {
 impl<D: Send + Clone + SecureDigest> Transcript for DigestTranscript<D> {
   type Challenge = Output<D>;
 
-  #[must_use]
   fn new(name: &'static [u8]) -> Self {
     let mut res = Self(D::new());
     res.append(DigestTranscriptMember::Name, name);