rust: use explicitily Integer::div_ceil

cf rust-lang/rust#88581

src/biguint.rs

@@ -390,7 +390,7 @@ impl Roots for BigUint {
                 // Try to guess by scaling down such that it does fit in `f64`.
                 // With some (x * 2ⁿᵏ), its nth root ≈ (ⁿ√x * 2ᵏ)
                 let extra_bits = bits - (core::f64::MAX_EXP as u64 - 1);
-                let root_scale = extra_bits.div_ceil(&n64);
+                let root_scale = Integer::div_ceil(&extra_bits, &n64);
                 let scale = root_scale * n64;
                 if scale < bits && bits - scale > n64 {
                     (self >> scale).nth_root(n) << root_scale

src/biguint/convert.rs

@@ -65,9 +65,8 @@ fn from_inexact_bitwise_digits_le(v: &[u8], bits: u8) -> BigUint {
     debug_assert!(!v.is_empty() && bits <= 8 && big_digit::BITS % bits != 0);
     debug_assert!(v.iter().all(|&c| BigDigit::from(c) < (1 << bits)));
 
-    let big_digits = (v.len() as u64)
-        .saturating_mul(bits.into())
-        .div_ceil(&big_digit::BITS.into())
+    let big_digits = (v.len() as u64).saturating_mul(bits.into());
+    let big_digits = Integer::div_ceil(&big_digits, &big_digit::BITS.into())
         .to_usize()
         .unwrap_or(core::usize::MAX);
     let mut data = Vec::with_capacity(big_digits);
@@ -580,9 +579,8 @@ pub(super) fn to_bitwise_digits_le(u: &BigUint, bits: u8) -> Vec<u8> {
     let last_i = u.data.len() - 1;
     let mask: BigDigit = (1 << bits) - 1;
     let digits_per_big_digit = big_digit::BITS / bits;
-    let digits = u
-        .bits()
-        .div_ceil(&u64::from(bits))
+    let digits = u.bits();
+    let digits = Integer::div_ceil(&digits, &u64::from(bits))
         .to_usize()
         .unwrap_or(core::usize::MAX);
     let mut res = Vec::with_capacity(digits);
@@ -608,9 +606,8 @@ fn to_inexact_bitwise_digits_le(u: &BigUint, bits: u8) -> Vec<u8> {
     debug_assert!(!u.is_zero() && bits <= 8 && big_digit::BITS % bits != 0);
 
     let mask: BigDigit = (1 << bits) - 1;
-    let digits = u
-        .bits()
-        .div_ceil(&u64::from(bits))
+    let digits = u.bits();
+    let digits = Integer::div_ceil(&digits, &u64::from(bits))
         .to_usize()
         .unwrap_or(core::usize::MAX);
     let mut res = Vec::with_capacity(digits);