diff --git a/src/plonk.rs b/src/plonk.rs
index 0aa9cb13..3df26898 100644
--- a/src/plonk.rs
+++ b/src/plonk.rs
@@ -213,14 +213,14 @@ fn test_proving() {
                 Variable(self.config.c, index),
             ))
         }
-        fn copy(&mut self, a: Variable, b: Variable) -> Result<(), Error> {
-            let left_wire = match a.0 {
+        fn copy(&mut self, left: Variable, right: Variable) -> Result<(), Error> {
+            let left_wire = match left.0 {
                 x if x == self.config.a => 0,
                 x if x == self.config.b => 1,
                 x if x == self.config.c => 2,
                 _ => unreachable!(),
             };
-            let right_wire = match b.0 {
+            let right_wire = match right.0 {
                 x if x == self.config.a => 0,
                 x if x == self.config.b => 1,
                 x if x == self.config.c => 2,
@@ -228,7 +228,7 @@ fn test_proving() {
             };
 
             self.cs
-                .copy(self.config.perm, left_wire, a.1, right_wire, b.1)
+                .copy(self.config.perm, left_wire, left.1, right_wire, right.1)
         }
     }
 
diff --git a/src/plonk/prover.rs b/src/plonk/prover.rs
index 609a4edc..1a1b709c 100644
--- a/src/plonk/prover.rs
+++ b/src/plonk/prover.rs
@@ -156,8 +156,8 @@ impl<C: CurveAffine> Proof<C> {
                     .iter_mut()
                     .zip(permuted_wire_values.iter())
                 {
-                    *tmp_advice_value += &(x_0 * permuted_advice_value);
-                    *tmp_advice_value += &x_1;
+                    *tmp_advice_value += &(x_0 * permuted_advice_value); // p_j(\omega^i) + \beta s_j(\omega^i)
+                    *tmp_advice_value += &x_1; // p_j(\omega^i) + \beta s_j(\omega^i) + \gamma
                 }
                 modified_advice.push(tmp_advice_values);
             }
@@ -175,15 +175,13 @@ impl<C: CurveAffine> Proof<C> {
                 // For each row i, we compute
                 // p_j(\omega^i) + \delta^j \omega^i \beta + \gamma
                 // for the jth wire of the permutation
-                for (advice_value, modified_advice) in witness.advice[wire.0]
+                for (tmp_advice_value, modified_advice) in witness.advice[wire.0]
                     .iter_mut()
                     .zip(modified_advice.iter_mut())
                 {
-                    let mut tmp = deltaomega; // \delta^j \omega^i
-                    tmp *= &x_0; // \delta^j \omega^i \beta
-                    tmp += &x_1; // \delta^j \omega^i \beta + \gamma
-                    tmp += advice_value; // p_j(\omega^i) + \delta^j \omega^i \beta + \gamma
-                    *modified_advice *= &tmp;
+                    *tmp_advice_value += &(deltaomega * &x_0); // p_j(\omega^i) + \delta^j \omega^i \beta
+                    *tmp_advice_value += &x_1; // p_j(\omega^i) + \delta^j \omega^i \beta + \gamma
+                    *modified_advice *= tmp_advice_value;
                     deltaomega *= &domain.get_omega();
                 }
                 deltaomega *= &C::Scalar::DELTA;
diff --git a/src/plonk/srs.rs b/src/plonk/srs.rs
index 4d73417f..86567c1e 100644
--- a/src/plonk/srs.rs
+++ b/src/plonk/srs.rs
@@ -157,7 +157,7 @@ impl<C: CurveAffine> SRS<C> {
         // the permutation arguments.
         for permutation in &meta.permutations {
             let mut wires = vec![];
-            for (i, _) in permutation.iter().enumerate() {
+            for i in 0..permutation.len() {
                 // Computes [(i, 0), (i, 1), ..., (i, n - 1)]
                 wires.push((0..params.n).map(|j| (i, j as usize)).collect());
             }
@@ -182,7 +182,7 @@ impl<C: CurveAffine> SRS<C> {
             let mut inner_permutations = vec![];
             let mut polys = vec![];
             let mut cosets = vec![];
-            for (i, _) in permutation.iter().enumerate() {
+            for i in 0..permutation.len() {
                 // Computes the permutation polynomial based on the permutation
                 // description in the assembly.
                 let permutation_poly: Vec<_> = (0..params.n as usize)