Use AffineCoordinates trait (#734)

Switches to the newly consolidated `AffineCoordinates` trait.

See RustCrypto/traits#1237

Cargo.toml

@@ -12,4 +12,8 @@ members = [
 ]
 
 [profile.dev]
-opt-level = 2
+opt-level = 2
+
+[patch.crates-io]
+ecdsa = { git = "https://github.com/RustCrypto/signatures.git" }
+elliptic-curve = { git = "https://github.com/RustCrypto/traits.git" }

k256/src/arithmetic/affine.rs

@@ -7,7 +7,7 @@ use crate::{CompressedPoint, EncodedPoint, FieldBytes, PublicKey, Scalar, Secp25
 use core::ops::{Mul, Neg};
 use elliptic_curve::{
     group::{prime::PrimeCurveAffine, GroupEncoding},
-    point::{AffineXCoordinate, AffineYIsOdd, DecompactPoint, DecompressPoint},
+    point::{AffineCoordinates, DecompactPoint, DecompressPoint},
     sec1::{self, FromEncodedPoint, ToEncodedPoint},
     subtle::{Choice, ConditionallySelectable, ConstantTimeEq, CtOption},
     zeroize::DefaultIsZeroes,
@@ -107,15 +107,13 @@ impl PrimeCurveAffine for AffinePoint {
     }
 }
 
-impl AffineXCoordinate for AffinePoint {
+impl AffineCoordinates for AffinePoint {
     type FieldRepr = FieldBytes;
 
     fn x(&self) -> FieldBytes {
         self.x.to_bytes()
     }
-}
 
-impl AffineYIsOdd for AffinePoint {
     fn y_is_odd(&self) -> Choice {
         self.y.normalize().is_odd()
     }

primeorder/src/affine.rs

@@ -11,7 +11,7 @@ use elliptic_curve::{
     ff::{Field, PrimeField},
     generic_array::ArrayLength,
     group::{prime::PrimeCurveAffine, GroupEncoding},
-    point::{AffineXCoordinate, AffineYIsOdd, DecompactPoint, DecompressPoint, Double},
+    point::{AffineCoordinates, DecompactPoint, DecompressPoint, Double},
     sec1::{
         self, CompressedPoint, EncodedPoint, FromEncodedPoint, ModulusSize, ToCompactEncodedPoint,
         ToEncodedPoint, UncompressedPointSize,
@@ -77,7 +77,7 @@ where
     }
 }
 
-impl<C> AffineXCoordinate for AffinePoint<C>
+impl<C> AffineCoordinates for AffinePoint<C>
 where
     C: PrimeCurveParams,
 {
@@ -86,12 +86,7 @@ where
     fn x(&self) -> FieldBytes<C> {
         self.x.to_repr()
     }
-}
 
-impl<C> AffineYIsOdd for AffinePoint<C>
-where
-    C: PrimeCurveParams,
-{
     fn y_is_odd(&self) -> Choice {
         self.y.is_odd()
     }