diff --git a/src/bellperson/mod.rs b/src/bellperson/mod.rs
index fc66cb3..5fef985 100644
--- a/src/bellperson/mod.rs
+++ b/src/bellperson/mod.rs
@@ -158,7 +158,7 @@ mod tests {
       n_limbs,
     )?;
 
-    let _ = a1.equal_when_carried(cs.namespace(|| "check equal"), &a2)?;
+    a1.equal_when_carried(cs.namespace(|| "check equal"), &a2)?;
     Ok(())
   }
 
@@ -182,7 +182,7 @@ mod tests {
       limb_width,
       n_limbs,
     )?;
-    let _ = m.inputize(cs.namespace(|| "modulus m"))?;
+    m.inputize(cs.namespace(|| "modulus m"))?;
 
     let a = BigNat::from_num(
       cs.namespace(|| "allocate a_limbs"),
@@ -228,14 +228,14 @@ mod tests {
       limb_width,
       n_limbs,
     )?;
-    let _ = a.inputize(cs.namespace(|| "input a"))?;
+    a.inputize(cs.namespace(|| "input a"))?;
     let b = BigNat::alloc_from_nat(
       cs.namespace(|| "b"),
       || Ok(b_val.clone()),
       limb_width,
       n_limbs,
     )?;
-    let _ = b.inputize(cs.namespace(|| "input b"))?;
+    b.inputize(cs.namespace(|| "input b"))?;
     let c = BigNat::alloc_from_nat(
       cs.namespace(|| "c"),
       || Ok(c_val.clone()),
@@ -262,14 +262,14 @@ mod tests {
       limb_width,
       n_limbs,
     )?;
-    let _ = a.inputize(cs.namespace(|| "input a"))?;
+    a.inputize(cs.namespace(|| "input a"))?;
     let b = BigNat::alloc_from_nat(
       cs.namespace(|| "b"),
       || Ok(b_val.clone()),
       limb_width,
       n_limbs,
     )?;
-    let _ = b.inputize(cs.namespace(|| "input b"))?;
+    b.inputize(cs.namespace(|| "input b"))?;
     let c = BigNat::alloc_from_nat(
       cs.namespace(|| "c"),
       || Ok(c_val.clone()),
diff --git a/src/bellperson/shape_cs.rs b/src/bellperson/shape_cs.rs
index 5b9ae60..982be24 100644
--- a/src/bellperson/shape_cs.rs
+++ b/src/bellperson/shape_cs.rs
@@ -6,9 +6,9 @@ use std::{
 };
 
 use crate::traits::Group;
-use ff::{Field, PrimeField};
-
 use bellperson::{ConstraintSystem, Index, LinearCombination, SynthesisError, Variable};
+use core::fmt::Write;
+use ff::{Field, PrimeField};
 
 #[derive(Clone, Copy)]
 struct OrderedVariable(Variable);
@@ -141,7 +141,7 @@ where
     let mut s = String::new();
 
     for input in &self.inputs {
-      s.push_str(&format!("INPUT {}\n", &input))
+      writeln!(s, "INPUT {}", &input).unwrap()
     }
 
     let negone = -<G::Scalar>::one();
@@ -164,20 +164,20 @@ where
         if coeff != <G::Scalar>::one() && coeff != negone {
           for (i, x) in powers_of_two.iter().enumerate() {
             if x == &coeff {
-              s.push_str(&format!("2^{} . ", i));
+              write!(s, "2^{} . ", i).unwrap();
               break;
             }
           }
 
-          s.push_str(&format!("{:?} . ", coeff))
+          write!(s, "{:?} . ", coeff).unwrap()
         }
 
         match var.0.get_unchecked() {
           Index::Input(i) => {
-            s.push_str(&format!("`I{}`", &self.inputs[i]));
+            write!(s, "`I{}`", &self.inputs[i]).unwrap();
           }
           Index::Aux(i) => {
-            s.push_str(&format!("`A{}`", &self.aux[i]));
+            write!(s, "`A{}`", &self.aux[i]).unwrap();
           }
         }
       }
@@ -191,9 +191,9 @@ where
     for &(ref a, ref b, ref c, ref name) in &self.constraints {
       s.push('\n');
 
-      s.push_str(&format!("{}: ", name));
+      write!(s, "{}: ", name).unwrap();
       pp(&mut s, a);
-      s.push_str(" * ");
+      write!(s, " * ").unwrap();
       pp(&mut s, b);
       s.push_str(" = ");
       pp(&mut s, c);
diff --git a/src/circuit.rs b/src/circuit.rs
index f44c01a..87a4e92 100644
--- a/src/circuit.rs
+++ b/src/circuit.rs
@@ -225,7 +225,7 @@ where
     ro.absorb(i);
     ro.absorb(z_0);
     ro.absorb(z_i);
-    let _ = U.absorb_in_ro(cs.namespace(|| "absorb U"), &mut ro)?;
+    U.absorb_in_ro(cs.namespace(|| "absorb U"), &mut ro)?;
 
     let hash_bits = ro.get_hash(cs.namespace(|| "Input hash"))?;
     let hash = le_bits_to_num(cs.namespace(|| "bits to hash"), hash_bits)?;
@@ -332,15 +332,14 @@ where
     ro.absorb(i_new.clone());
     ro.absorb(z_0);
     ro.absorb(z_next);
-    let _ = Unew.absorb_in_ro(cs.namespace(|| "absorb U_new"), &mut ro)?;
+    Unew.absorb_in_ro(cs.namespace(|| "absorb U_new"), &mut ro)?;
     let hash_bits = ro.get_hash(cs.namespace(|| "output hash bits"))?;
     let hash = le_bits_to_num(cs.namespace(|| "convert hash to num"), hash_bits)?;
 
     // Outputs the computed hash and u.X[1] that corresponds to the hash of the other circuit
-    let _ = u
-      .X1
+    u.X1
       .inputize(cs.namespace(|| "Output unmodified hash of the other circuit"))?;
-    let _ = hash.inputize(cs.namespace(|| "output new hash of this circuit"))?;
+    hash.inputize(cs.namespace(|| "output new hash of this circuit"))?;
 
     Ok(())
   }
diff --git a/src/gadgets/ecc.rs b/src/gadgets/ecc.rs
index d7a779b..a82674c 100644
--- a/src/gadgets/ecc.rs
+++ b/src/gadgets/ecc.rs
@@ -740,7 +740,7 @@ mod tests {
     CS: ConstraintSystem<Fp>,
   {
     let a = AllocatedPoint::<Fp>::random_vartime(cs.namespace(|| "a")).unwrap();
-    let _ = a.inputize(cs.namespace(|| "inputize a")).unwrap();
+    a.inputize(cs.namespace(|| "inputize a")).unwrap();
     let s = Fq::random(&mut OsRng);
     // Allocate random bits and only keep 128 bits
     let bits: Vec<AllocatedBit> = s
@@ -751,7 +751,7 @@ mod tests {
       .collect::<Result<Vec<AllocatedBit>, SynthesisError>>()
       .unwrap();
     let e = a.scalar_mul(cs.namespace(|| "Scalar Mul"), bits).unwrap();
-    let _ = e.inputize(cs.namespace(|| "inputize e")).unwrap();
+    e.inputize(cs.namespace(|| "inputize e")).unwrap();
     (a, e, s)
   }
 
@@ -792,9 +792,9 @@ mod tests {
     CS: ConstraintSystem<Fp>,
   {
     let a = AllocatedPoint::<Fp>::random_vartime(cs.namespace(|| "a")).unwrap();
-    let _ = a.inputize(cs.namespace(|| "inputize a")).unwrap();
+    a.inputize(cs.namespace(|| "inputize a")).unwrap();
     let e = a.add(cs.namespace(|| "add a to a"), &a).unwrap();
-    let _ = e.inputize(cs.namespace(|| "inputize e")).unwrap();
+    e.inputize(cs.namespace(|| "inputize e")).unwrap();
     (a, e)
   }
 
@@ -834,11 +834,11 @@ mod tests {
     CS: ConstraintSystem<Fp>,
   {
     let a = AllocatedPoint::<Fp>::random_vartime(cs.namespace(|| "a")).unwrap();
-    let _ = a.inputize(cs.namespace(|| "inputize a")).unwrap();
+    a.inputize(cs.namespace(|| "inputize a")).unwrap();
     let mut b = a.clone();
     b.y =
       AllocatedNum::alloc(cs.namespace(|| "allocate negation of a"), || Ok(Fp::zero())).unwrap();
-    let _ = b.inputize(cs.namespace(|| "inputize b")).unwrap();
+    b.inputize(cs.namespace(|| "inputize b")).unwrap();
     let e = a.add(cs.namespace(|| "add a to b"), &b).unwrap();
     e
   }
diff --git a/src/poseidon.rs b/src/poseidon.rs
index 961788a..d389499 100644
--- a/src/poseidon.rs
+++ b/src/poseidon.rs
@@ -244,7 +244,7 @@ mod tests {
       ro.absorb(num);
       let num_gadget =
         AllocatedNum::alloc(cs.namespace(|| format!("data {}", i)), || Ok(num)).unwrap();
-      let _ = num_gadget
+      num_gadget
         .inputize(&mut cs.namespace(|| format!("input {}", i)))
         .unwrap();
       ro_gadget.absorb(num_gadget);