diff --git a/src/composer/prover.rs b/src/composer/prover.rs
index ee941f2a..2ec7b08f 100644
--- a/src/composer/prover.rs
+++ b/src/composer/prover.rs
@@ -88,7 +88,7 @@ impl Prover {
         for i in 0..hiding_degree + 1 {
             let blinding_scalar = BlsScalar::random(&mut *rng);
 
-            w_vec_inverse[i] = w_vec_inverse[i] - blinding_scalar;
+            w_vec_inverse[i] -= blinding_scalar;
             w_vec_inverse.push(blinding_scalar);
         }
 
@@ -364,15 +364,15 @@ impl Prover {
         t_low_vec.push(b_10);
 
         // t_mid'(X) - b_10 + b_11*X^n
-        t_mid_vec[0] = t_mid_vec[0] - b_10;
+        t_mid_vec[0] -= b_10;
         t_mid_vec.push(b_11);
 
         // t_high'(X) - b_11 + b_12*X^n
-        t_high_vec[0] = t_high_vec[0] - b_11;
+        t_high_vec[0] -= b_11;
         t_high_vec.push(b_12);
 
         // t_4'(X) - b_12
-        t_4_vec[0] = t_4_vec[0] - b_12;
+        t_4_vec[0] -= b_12;
 
         let t_low_poly = FftPolynomial::from_coefficients_vec(t_low_vec);
         let t_mid_poly = FftPolynomial::from_coefficients_vec(t_mid_vec);
diff --git a/tests/logic.rs b/tests/logic.rs
index 5b24007a..9e8a8fcb 100644
--- a/tests/logic.rs
+++ b/tests/logic.rs
@@ -191,6 +191,7 @@ fn append_logic_and() {
     );
 }
 
+#[ignore = "see issue #777"]
 #[test]
 fn append_logic_xor() {
     #[derive(Default)]
@@ -239,8 +240,8 @@ fn append_logic_xor() {
     let label = b"append_logic_xor";
 
     // FIXME: One test used to fail when using "0xdea1" as randomness here. It
-    // needs to be tackcled soon or later.
-    let mut rng = StdRng::seed_from_u64(0xded1);
+    // needs to be tackled soon or later.
+    let mut rng = StdRng::seed_from_u64(0xdea1);
     let capacity = 1 << 8;
     let pp = PublicParameters::setup(capacity, &mut rng)
         .expect("Creation of public parameter shouldn't fail");