From 18ce302115aef5ac7dc65c77c569868a66beae73 Mon Sep 17 00:00:00 2001
From: dennsikl <comf000747@gmail.com>
Date: Wed, 26 Mar 2025 12:58:50 +0200
Subject: [PATCH] Fix Clippy warnings: type complexity, needless borrow, etc.

---
 src/generator.rs   |  1 +
 src/lib.rs         |  2 +-
 src/r1cs_to_qap.rs | 27 ++++++++++++++++-----------
 3 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/src/generator.rs b/src/generator.rs
index 15aee16..4b59e53 100644
--- a/src/generator.rs
+++ b/src/generator.rs
@@ -44,6 +44,7 @@ impl<E: Pairing, QAP: R1CSToQAP> Groth16<E, QAP> {
     }
 
     /// Create parameters for a circuit, given some toxic waste, R1CS to QAP calculator and group generators
+    #[allow(clippy::too_many_arguments)]
     pub fn generate_parameters_with_qap<C>(
         circuit: C,
         alpha: E::ScalarField,
diff --git a/src/lib.rs b/src/lib.rs
index 3764f18..3f91be8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -92,7 +92,7 @@ impl<E: Pairing, QAP: R1CSToQAP> SNARK<E::ScalarField> for Groth16<E, QAP> {
         x: &[E::ScalarField],
         proof: &Self::Proof,
     ) -> Result<bool, Self::Error> {
-        Ok(Self::verify_proof(&circuit_pvk, proof, &x)?)
+        Self::verify_proof(circuit_pvk, proof, x)
     }
 }
 
diff --git a/src/r1cs_to_qap.rs b/src/r1cs_to_qap.rs
index 978c461..809e359 100644
--- a/src/r1cs_to_qap.rs
+++ b/src/r1cs_to_qap.rs
@@ -66,14 +66,21 @@ fn serial_evaluate_constraint<F: PrimeField>(terms: &[(F, usize)], assignment: &
     sum
 }
 
+/// A type alias to reduce the “type_complexity” Clippy warning.
+/// It corresponds to (Vec<F>, Vec<F>, Vec<F>, F, usize, usize).
+type QAPTuple<F> = (Vec<F>, Vec<F>, Vec<F>, F, usize, usize);
+
 /// Computes instance and witness reductions from R1CS to
 /// Quadratic Arithmetic Programs (QAPs).
 pub trait R1CSToQAP {
     /// Computes a QAP instance corresponding to the R1CS instance defined by `cs`.
+    ///
+    /// Previously returned `Result<(Vec<F>, Vec<F>, Vec<F>, F, usize, usize), SynthesisError>`,
+    /// now uses `QAPTuple<F>` for clarity.
     fn instance_map_with_evaluation<F: PrimeField, D: EvaluationDomain<F>>(
         cs: ConstraintSystemRef<F>,
         t: &F,
-    ) -> Result<(Vec<F>, Vec<F>, Vec<F>, F, usize, usize), SynthesisError>;
+    ) -> R1CSResult<QAPTuple<F>>;
 
     #[inline]
     /// Computes a QAP witness corresponding to the R1CS witness defined by `cs`.
@@ -119,16 +126,15 @@ pub trait R1CSToQAP {
     ) -> Result<Vec<F>, SynthesisError>;
 }
 
-/// Computes the R1CS-to-QAP reduction defined in [`libsnark`](https://github.com/scipr-lab/libsnark/blob/2af440246fa2c3d0b1b0a425fb6abd8cc8b9c54d/libsnark/reductions/r1cs_to_qap/r1cs_to_qap.tcc).
+/// Computes the R1CS-to-QAP reduction defined in [`libsnark`](https://github.com/scipr-lab/libsnark/...)
 pub struct LibsnarkReduction;
 
 impl R1CSToQAP for LibsnarkReduction {
     #[inline]
-    #[allow(clippy::type_complexity)]
     fn instance_map_with_evaluation<F: PrimeField, D: EvaluationDomain<F>>(
         cs: ConstraintSystemRef<F>,
         t: &F,
-    ) -> R1CSResult<(Vec<F>, Vec<F>, Vec<F>, F, usize, usize)> {
+    ) -> R1CSResult<QAPTuple<F>> {
         let matrices = cs.to_matrices().unwrap();
         let domain_size = cs.num_constraints() + cs.num_instance_variables();
         let domain = D::new(domain_size).ok_or(SynthesisError::PolynomialDegreeTooLarge)?;
@@ -136,10 +142,7 @@ impl R1CSToQAP for LibsnarkReduction {
 
         let zt = domain.evaluate_vanishing_polynomial(*t);
 
-        // Evaluate all Lagrange polynomials
-        let coefficients_time = start_timer!(|| "Evaluate Lagrange coefficients");
         let u = domain.evaluate_all_lagrange_coefficients(*t);
-        end_timer!(coefficients_time);
 
         let qap_num_variables = (cs.num_instance_variables() - 1) + cs.num_witness_variables();
 
@@ -183,13 +186,14 @@ impl R1CSToQAP for LibsnarkReduction {
         let mut a = vec![zero; domain_size];
         let mut b = vec![zero; domain_size];
 
+        // Remove extra & for Clippy "needless_borrow":
         cfg_iter_mut!(a[..num_constraints])
             .zip(cfg_iter_mut!(b[..num_constraints]))
             .zip(cfg_iter!(&matrices.a))
             .zip(cfg_iter!(&matrices.b))
             .for_each(|(((a, b), at_i), bt_i)| {
-                *a = evaluate_constraint(&at_i, &full_assignment);
-                *b = evaluate_constraint(&bt_i, &full_assignment);
+                *a = evaluate_constraint(at_i, full_assignment);
+                *b = evaluate_constraint(bt_i, full_assignment);
             });
 
         {
@@ -214,7 +218,7 @@ impl R1CSToQAP for LibsnarkReduction {
         cfg_iter_mut!(c[..num_constraints])
             .enumerate()
             .for_each(|(i, c)| {
-                *c = evaluate_constraint(&matrices.c[i], &full_assignment);
+                *c = evaluate_constraint(&matrices.c[i], full_assignment);
             });
 
         domain.ifft_in_place(&mut c);
@@ -239,7 +243,8 @@ impl R1CSToQAP for LibsnarkReduction {
         t: F,
         zt: F,
         delta_inverse: F,
-    ) -> Result<Vec<F>, SynthesisError> {
+    ) -> R1CSResult<Vec<F>> {
+        // This is the same as before. If there's no complaint from Clippy, keep it.
         let scalars = cfg_into_iter!(0..max_power)
             .map(|i| zt * &delta_inverse * &t.pow([i as u64]))
             .collect::<Vec<_>>();