Implement Hash Manually (#47)

Addresses a clippy lint that you should not derive `Hash` and implement
`PartialEq`.

Author: nlordell

src/int.rs

@@ -13,7 +13,7 @@ use crate::uint::U256;
 use core::{mem::MaybeUninit, num::ParseIntError};
 
 /// A 256-bit signed integer type.
-#[derive(Clone, Copy, Default, Eq, Hash)]
+#[derive(Clone, Copy, Default, Eq)]
 #[repr(transparent)]
 pub struct I256(pub [i128; 2]);
 

src/macros/cmp.rs

@@ -4,10 +4,13 @@ macro_rules! impl_cmp {
     (
         impl Cmp for $int:ident ($prim:ident);
     ) => {
-        impl PartialOrd for $int {
+        impl ::core::hash::Hash for $int {
             #[inline]
-            fn partial_cmp(&self, other: &Self) -> Option<::core::cmp::Ordering> {
-                Some(self.cmp(other))
+            fn hash<H>(&self, hasher: &mut H)
+            where
+                H: ::core::hash::Hasher,
+            {
+                ::core::hash::Hash::hash(&self.0, hasher);
             }
         }
 
@@ -36,6 +39,13 @@ macro_rules! impl_cmp {
             }
         }
 
+        impl PartialOrd for $int {
+            #[inline]
+            fn partial_cmp(&self, other: &Self) -> Option<::core::cmp::Ordering> {
+                Some(self.cmp(other))
+            }
+        }
+
         impl PartialOrd<$prim> for $int {
             #[inline]
             fn partial_cmp(&self, rhs: &$prim) -> Option<::core::cmp::Ordering> {

src/uint.rs

@@ -13,7 +13,7 @@ use crate::I256;
 use core::{mem::MaybeUninit, num::ParseIntError};
 
 /// A 256-bit unsigned integer type.
-#[derive(Clone, Copy, Default, Eq, Hash)]
+#[derive(Clone, Copy, Default, Eq)]
 #[repr(transparent)]
 pub struct U256(pub [u128; 2]);