From ee29fb4b848558eca2826c0887b48e30ea617045 Mon Sep 17 00:00:00 2001
From: Volker Mische <volker.mische@gmail.com>
Date: Wed, 1 Jun 2022 18:38:10 +0200
Subject: [PATCH] Revive base field type on Curve trait

Curves operate on certain base fields. Sometimes in can be useful to have
a direct reference to which field this is. With the `Base` associate type
you can not get that information.

More concretely this will be used by some GPU code, which needs access to
the information which base field a curve operates on.

BREAKING CHANGE: crates implementing `Curve` need to define the `Base`.
---
 src/lib.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/lib.rs b/src/lib.rs
index 1ef6bc9..749bff6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -12,7 +12,7 @@ pub use ff;
 use core::fmt;
 use core::iter::Sum;
 use core::ops::{Add, AddAssign, Mul, MulAssign, Neg, Sub, SubAssign};
-use ff::PrimeField;
+use ff::{Field, PrimeField};
 use rand_core::RngCore;
 use subtle::{Choice, CtOption};
 
@@ -96,6 +96,9 @@ pub trait Group:
 pub trait Curve:
     Group + GroupOps<<Self as Curve>::AffineRepr> + GroupOpsOwned<<Self as Curve>::AffineRepr>
 {
+    /// The base field of the elliptic curve.
+    type Base: Field;
+
     /// The affine representation for this elliptic curve.
     type AffineRepr;