factor: Get rid of the custom OverflowingAdd trait (#1697)

* factor: Confine knowledge of num_traits to numeric::traits

This should make it easier to deal with API changes of num_traits,
or eventually switching to an abstraction provided in the stdlib.

src/uu/factor/Cargo.toml

@@ -12,11 +12,11 @@ categories = ["command-line-utilities"]
 edition = "2018"
 
 [build-dependencies]
-num-traits = "0.2" # used in src/numerics.rs, which is included by build.rs
+num-traits = "0.2.13" # used in src/numerics.rs, which is included by build.rs
 
 
 [dependencies]
-num-traits = "0.2"
+num-traits = "0.2.13" # Needs at least version 0.2.13 for "OverflowingAdd"
 rand = { version="0.7", features=["small_rng"] }
 smallvec = { version="0.6.13, < 1.0" }
 uucore = { version=">=0.0.5", package="uucore", path="../../uucore" }

src/uu/factor/build.rs

@@ -29,6 +29,7 @@ use miller_rabin::is_prime;
 
 #[path = "src/numeric/modular_inverse.rs"]
 mod modular_inverse;
+#[allow(unused_imports)] // imports there are used, but invisible from build.rs
 #[path = "src/numeric/traits.rs"]
 mod traits;
 use modular_inverse::modular_inverse;

src/uu/factor/src/numeric/montgomery.rs

@@ -8,8 +8,7 @@
 
 use super::*;
 
-use num_traits::identities::{One, Zero};
+use traits::{DoubleInt, Int, One, OverflowingAdd, Zero};
-use traits::{DoubleInt, Int, OverflowingAdd};
 
 pub(crate) trait Arithmetic: Copy + Sized {
     // The type of integers mod m, in some opaque representation
@@ -74,7 +73,7 @@ impl<T: DoubleInt> Montgomery<T> {
         let Montgomery { a, n } = self;
         let m = T::from_double_width(x).wrapping_mul(a);
         let nm = (n.as_double_width()) * (m.as_double_width());
-        let (xnm, overflow) = x.overflowing_add_(nm); // x + n*m
+        let (xnm, overflow) = x.overflowing_add(&nm); // x + n*m
         debug_assert_eq!(
             xnm % (T::DoubleWidth::one() << T::zero().count_zeros() as usize),
             T::DoubleWidth::zero()
@@ -130,7 +129,7 @@ impl<T: DoubleInt> Arithmetic for Montgomery<T> {
     }
 
     fn add(&self, a: Self::ModInt, b: Self::ModInt) -> Self::ModInt {
-        let (r, overflow) = a.overflowing_add_(b);
+        let (r, overflow) = a.overflowing_add(&b);
 
         // In case of overflow, a+b = 2⁶⁴ + r = (2⁶⁴ - n) + r (working mod n)
         let r = if !overflow {

src/uu/factor/src/numeric/traits.rs

@@ -6,31 +6,16 @@
 // * For the full copyright and license information, please view the LICENSE file
 // * that was distributed with this source code.
 
+pub(crate) use num_traits::{
+    identities::{One, Zero},
+    ops::overflowing::OverflowingAdd,
+};
 use num_traits::{
     int::PrimInt,
     ops::wrapping::{WrappingMul, WrappingNeg, WrappingSub},
 };
 use std::fmt::{Debug, Display};
 
-// NOTE: Trait can be removed once num-traits adds a similar one;
-//       see https://github.com/rust-num/num-traits/issues/168
-pub(crate) trait OverflowingAdd: Sized {
-    fn overflowing_add_(self, n: Self) -> (Self, bool);
-}
-
-macro_rules! overflowing {
-    ($x:ty) => {
-        impl OverflowingAdd for $x {
-            fn overflowing_add_(self, n: Self) -> (Self, bool) {
-                self.overflowing_add(n)
-            }
-        }
-    };
-}
-overflowing!(u32);
-overflowing!(u64);
-overflowing!(u128);
-
 pub(crate) trait Int:
     Display + Debug + PrimInt + OverflowingAdd + WrappingNeg + WrappingSub + WrappingMul
 {