From 80429064848809675c41c7859631aa4dc07c55e4 Mon Sep 17 00:00:00 2001
From: David Nevado <david@davidnevado.xyz>
Date: Mon, 7 Mar 2022 11:19:15 +0100
Subject: [PATCH 1/3] Change `Coordinates` fields to `pub`

---
 src/arithmetic/curves.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/arithmetic/curves.rs b/src/arithmetic/curves.rs
index ca94e58..d718fc2 100644
--- a/src/arithmetic/curves.rs
+++ b/src/arithmetic/curves.rs
@@ -134,8 +134,10 @@ pub trait CurveAffine:
 #[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
 #[derive(Clone, Copy, Debug, Default)]
 pub struct Coordinates<C: CurveAffine> {
-    pub(crate) x: C::Base,
-    pub(crate) y: C::Base,
+    /// x-coordinate of the EC point.
+    pub x: C::Base,
+    /// y-coordinate of the EC point.
+    pub y: C::Base,
 }
 
 #[cfg(feature = "alloc")]

From 8a3643682fbde3343b9ca9aab1883757b3223213 Mon Sep 17 00:00:00 2001
From: David Nevado <david@davidnevado.xyz>
Date: Sat, 12 Mar 2022 15:42:57 +0100
Subject: [PATCH 2/3] Change `Coordinates` attrs back to `pub(crate)`

---
 src/arithmetic/curves.rs | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/src/arithmetic/curves.rs b/src/arithmetic/curves.rs
index d718fc2..ca94e58 100644
--- a/src/arithmetic/curves.rs
+++ b/src/arithmetic/curves.rs
@@ -134,10 +134,8 @@ pub trait CurveAffine:
 #[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
 #[derive(Clone, Copy, Debug, Default)]
 pub struct Coordinates<C: CurveAffine> {
-    /// x-coordinate of the EC point.
-    pub x: C::Base,
-    /// y-coordinate of the EC point.
-    pub y: C::Base,
+    pub(crate) x: C::Base,
+    pub(crate) y: C::Base,
 }
 
 #[cfg(feature = "alloc")]

From 8b101d67c4408c1191dd0bb1ace2b9bc50b37553 Mon Sep 17 00:00:00 2001
From: David Nevado <david@davidnevado.xyz>
Date: Sat, 12 Mar 2022 15:46:43 +0100
Subject: [PATCH 3/3] Add `Coordinates` constructor

---
 src/arithmetic/curves.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/arithmetic/curves.rs b/src/arithmetic/curves.rs
index ca94e58..44eced6 100644
--- a/src/arithmetic/curves.rs
+++ b/src/arithmetic/curves.rs
@@ -140,6 +140,11 @@ pub struct Coordinates<C: CurveAffine> {
 
 #[cfg(feature = "alloc")]
 impl<C: CurveAffine> Coordinates<C> {
+    /// Obtains a `Coordinates` value given $(x, y)$, failing if it is not on the curve.
+    pub fn from_xy(x: C::Base, y: C::Base) -> CtOption<Self> {
+        // We use CurveAffine::from_xy to validate the coordinates.
+        C::from_xy(x, y).map(|_| Coordinates { x, y })
+    }
     /// Returns the x-coordinate.
     ///
     /// Equivalent to `Coordinates::u`.