Fix clippy (#1662)

Author: Nashtare

field/src/fft.rs

@@ -222,7 +222,7 @@ mod tests {
         // "random", the last degree_padded-degree of them are zero.
         let coeffs = (0..degree)
             .map(|i| F::from_canonical_usize(i * 1337 % 100))
-            .chain(core::iter::repeat(F::ZERO).take(degree_padded - degree))
+            .chain(core::iter::repeat_n(F::ZERO, degree_padded - degree))
             .collect::<Vec<_>>();
         assert_eq!(coeffs.len(), degree_padded);
         let coefficients = PolynomialCoeffs { coeffs };

field/src/prime_field_testing.rs

@@ -160,7 +160,7 @@ macro_rules! test_prime_field_arithmetic {
             fn subtraction_double_wraparound() {
                 type F = $field;
 
-                let (a, b) = (F::from_canonical_u64((F::ORDER + 1u64) / 2u64), F::TWO);
+                let (a, b) = (F::from_canonical_u64(F::ORDER.div_ceil(2u64)), F::TWO);
                 let x = a * b;
                 assert_eq!(x, F::ONE);
                 assert_eq!(F::ZERO - x, F::NEG_ONE);