refactor: Bump toolchain and clean lints (#387)

- Upgraded the Rust toolchain version.
- clippy

examples/hashchain.rs

@@ -92,9 +92,9 @@ impl<G: Group> StepCircuit<G::Scalar> for HashChainCircuit<G> {
       let acc = &mut ns;
 
       sponge.start(parameter, None, acc);
-      neptune::sponge::api::SpongeAPI::absorb(&mut sponge, num_absorbs, &elt, acc);
+      SpongeAPI::absorb(&mut sponge, num_absorbs, &elt, acc);
 
-      let output = neptune::sponge::api::SpongeAPI::squeeze(&mut sponge, 1, acc);
+      let output = SpongeAPI::squeeze(&mut sponge, 1, acc);
       sponge.finish(acc).unwrap();
       Elt::ensure_allocated(&output[0], &mut ns.namespace(|| "ensure allocated"), true)?
     };

rust-toolchain.toml

@@ -1,6 +1,6 @@
 [toolchain]
 # The default profile includes rustc, rust-std, cargo, rust-docs, rustfmt and clippy.
 profile = "default"
-channel = "1.77"
+channel = "1.78"
 targets = [ "wasm32-unknown-unknown" ]
 

src/gadgets/nonnative/mod.rs

@@ -6,16 +6,12 @@ use ff::PrimeField;
 
 trait OptionExt<T> {
   fn grab(&self) -> Result<&T, SynthesisError>;
-  fn grab_mut(&mut self) -> Result<&mut T, SynthesisError>;
 }
 
 impl<T> OptionExt<T> for Option<T> {
   fn grab(&self) -> Result<&T, SynthesisError> {
     self.as_ref().ok_or(SynthesisError::AssignmentMissing)
   }
-  fn grab_mut(&mut self) -> Result<&mut T, SynthesisError> {
-    self.as_mut().ok_or(SynthesisError::AssignmentMissing)
-  }
 }
 
 trait BitAccess {

src/provider/poseidon.rs

@@ -169,7 +169,7 @@ where
       assert_eq!(self.num_absorbs, self.state.len());
 
       sponge.start(parameter, None, acc);
-      neptune::sponge::api::SpongeAPI::absorb(
+      SpongeAPI::absorb(
         &mut sponge,
         self.num_absorbs as u32,
         &(0..self.state.len())
@@ -178,7 +178,7 @@ where
         acc,
       );
 
-      let output = neptune::sponge::api::SpongeAPI::squeeze(&mut sponge, 1, acc);
+      let output = SpongeAPI::squeeze(&mut sponge, 1, acc);
       sponge.finish(acc).unwrap();
       output
     };

src/provider/tests/mod.rs

@@ -25,7 +25,7 @@ pub mod solidity_compatibility_utils {
   ) {
     use rand_core::SeedableRng;
 
-    let mut rng = rand::rngs::StdRng::seed_from_u64(num_vars as u64);
+    let mut rng = StdRng::seed_from_u64(num_vars as u64);
 
     let (poly, point, eval) =
       crate::provider::util::test_utils::random_poly_with_eval::<E, StdRng>(num_vars, &mut rng);

src/provider/util/mod.rs

@@ -146,7 +146,7 @@ pub mod test_utils {
   ) {
     use rand_core::SeedableRng;
 
-    let mut rng = rand::rngs::StdRng::seed_from_u64(num_vars as u64);
+    let mut rng = StdRng::seed_from_u64(num_vars as u64);
 
     let (poly, point, eval) = random_poly_with_eval::<E, StdRng>(num_vars, &mut rng);
 

src/spartan/math.rs

@@ -1,23 +1,8 @@
 pub trait Math {
-  fn pow2(self) -> usize;
-  fn get_bits(self, num_bits: usize) -> Vec<bool>;
   fn log_2(self) -> usize;
 }
 
 impl Math for usize {
-  #[inline]
-  fn pow2(self) -> usize {
-    let base: Self = 2;
-    base.pow(self as u32)
-  }
-
-  /// Returns the `num_bits` from n in a canonical order
-  fn get_bits(self, num_bits: usize) -> Vec<bool> {
-    (0..num_bits)
-      .map(|shift_amount| ((self & (1 << (num_bits - shift_amount - 1))) > 0))
-      .collect::<Vec<bool>>()
-  }
-
   fn log_2(self) -> usize {
     assert_ne!(self, 0);
 

src/spartan/polys/multilinear.rs

@@ -181,7 +181,7 @@ impl<Scalar: PrimeField> Add for MultilinearPolynomial<Scalar> {
 
 #[cfg(test)]
 mod tests {
-  use crate::provider::{self, bn256_grumpkin::bn256, secp_secq::secp256k1};
+  use crate::provider::{bn256_grumpkin::bn256, secp_secq::secp256k1};
 
   use super::*;
   use rand_chacha::ChaCha20Rng;
@@ -293,8 +293,8 @@ mod tests {
   #[test]
   fn test_evaluation() {
     test_evaluation_with::<pasta_curves::Fp>();
-    test_evaluation_with::<provider::bn256_grumpkin::bn256::Scalar>();
-    test_evaluation_with::<provider::secp_secq::secp256k1::Scalar>();
+    test_evaluation_with::<bn256::Scalar>();
+    test_evaluation_with::<secp256k1::Scalar>();
   }
 
   /// This binds the variables of a multilinear polynomial to a provided sequence

src/supernova/mod.rs

@@ -1155,19 +1155,6 @@ where
   fn secondary_circuit(&self) -> Self::C2;
 }
 
-/// Extension trait to simplify getting scalar form of initial circuit index.
-trait InitialProgramCounter<E1>: NonUniformCircuit<E1>
-where
-  E1: CurveCycleEquipped,
-{
-  /// Initial program counter is the initial circuit index as a `Scalar`.
-  fn initial_program_counter(&self) -> E1::Scalar {
-    E1::Scalar::from(self.initial_circuit_index() as u64)
-  }
-}
-
-impl<E1: CurveCycleEquipped, T: NonUniformCircuit<E1>> InitialProgramCounter<E1> for T {}
-
 /// Compute the circuit digest of a supernova [`StepCircuit`].
 ///
 /// Note for callers: This function should be called with its performance characteristics in mind.