Fix the PartialEq impl for quaternions.

The double-covering property should only be taken into account for `UnitQuaternion` instead of `Quaternion` itself.

src/base/unit.rs

@@ -11,7 +11,8 @@ use abomonation::Abomonation;
 
 use crate::allocator::Allocator;
 use crate::base::DefaultAllocator;
-use crate::{Dim, MatrixMN, RealField, Scalar, SimdComplexField, SimdRealField};
+use crate::storage::Storage;
+use crate::{Dim, Matrix, MatrixMN, RealField, Scalar, SimdComplexField, SimdRealField};
 
 /// A wrapper that ensures the underlying algebraic entity has a unit norm.
 ///
@@ -24,7 +25,7 @@ use crate::{Dim, MatrixMN, RealField, Scalar, SimdComplexField, SimdRealField};
 /// and [`UnitQuaternion`](crate::UnitQuaternion); both built on top of `Unit`.  If you are interested
 /// in their documentation, read their dedicated pages directly.
 #[repr(transparent)]
-#[derive(Eq, PartialEq, Clone, Hash, Debug, Copy)]
+#[derive(Clone, Hash, Debug, Copy)]
 pub struct Unit<T> {
     pub(crate) value: T,
 }
@@ -64,6 +65,28 @@ impl<T: Abomonation> Abomonation for Unit<T> {
     }
 }
 
+impl<N, R, C, S> PartialEq for Unit<Matrix<N, R, C, S>>
+where
+    N: Scalar + PartialEq,
+    R: Dim,
+    C: Dim,
+    S: Storage<N, R, C>,
+{
+    #[inline]
+    fn eq(&self, rhs: &Self) -> bool {
+        self.value.eq(&rhs.value)
+    }
+}
+
+impl<N, R, C, S> Eq for Unit<Matrix<N, R, C, S>>
+where
+    N: Scalar + Eq,
+    R: Dim,
+    C: Dim,
+    S: Storage<N, R, C>,
+{
+}
+
 /// Trait implemented by entities scan be be normalized and put in an `Unit` struct.
 pub trait Normed {
     /// The type of the norm.

src/geometry/quaternion.rs

@@ -13,7 +13,7 @@ use serde::{Deserialize, Deserializer, Serialize, Serializer};
 #[cfg(feature = "abomonation-serialize")]
 use abomonation::Abomonation;
 
-use simba::scalar::RealField;
+use simba::scalar::{ClosedNeg, RealField};
 use simba::simd::{SimdBool, SimdOption, SimdRealField, SimdValue};
 
 use crate::base::dimension::{U1, U3, U4};
@@ -23,17 +23,18 @@ use crate::base::{
 };
 
 use crate::geometry::{Point3, Rotation};
+use std::ops::Neg;
 
 /// A quaternion. See the type alias `UnitQuaternion = Unit<Quaternion>` for a quaternion
 /// that may be used as a rotation.
 #[repr(C)]
-#[derive(Debug)]
-pub struct Quaternion<N: Scalar + SimdValue> {
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+pub struct Quaternion<N: Scalar> {
     /// This quaternion as a 4D vector of coordinates in the `[ x, y, z, w ]` storage order.
     pub coords: Vector4<N>,
 }
 
-impl<N: RealField> Default for Quaternion<N> {
+impl<N: Scalar + Zero> Default for Quaternion<N> {
     fn default() -> Self {
         Quaternion {
             coords: Vector4::zeros(),
@@ -42,7 +43,7 @@ impl<N: RealField> Default for Quaternion<N> {
 }
 
 #[cfg(feature = "abomonation-serialize")]
-impl<N: SimdRealField> Abomonation for Quaternion<N>
+impl<N: Scalar> Abomonation for Quaternion<N>
 where
     Vector4<N>: Abomonation,
 {
@@ -59,36 +60,8 @@ where
     }
 }
 
-impl<N: SimdRealField + Eq> Eq for Quaternion<N> where N::Element: SimdRealField {}
-
-impl<N: SimdRealField> PartialEq for Quaternion<N>
-where
-    N::Element: SimdRealField,
-{
-    fn eq(&self, rhs: &Self) -> bool {
-        self.coords == rhs.coords ||
-        // Account for the double-covering of S², i.e. q = -q
-        self.as_vector().iter().zip(rhs.as_vector().iter()).all(|(a, b)| *a == -*b)
-    }
-}
-
-impl<N: SimdRealField + hash::Hash> hash::Hash for Quaternion<N> {
-    fn hash<H: hash::Hasher>(&self, state: &mut H) {
-        self.coords.hash(state)
-    }
-}
-
-impl<N: Scalar + Copy + SimdValue> Copy for Quaternion<N> {}
-
-impl<N: Scalar + SimdValue> Clone for Quaternion<N> {
-    #[inline]
-    fn clone(&self) -> Self {
-        Self::from(self.coords.clone())
-    }
-}
-
 #[cfg(feature = "serde-serialize")]
-impl<N: SimdRealField> Serialize for Quaternion<N>
+impl<N: Scalar> Serialize for Quaternion<N>
 where
     Owned<N, U4>: Serialize,
 {
@@ -101,7 +74,7 @@ where
 }
 
 #[cfg(feature = "serde-serialize")]
-impl<'a, N: SimdRealField> Deserialize<'a> for Quaternion<N>
+impl<'a, N: Scalar> Deserialize<'a> for Quaternion<N>
 where
     Owned<N, U4>: Deserialize<'a>,
 {
@@ -980,6 +953,17 @@ impl<N: RealField + fmt::Display> fmt::Display for Quaternion<N> {
 /// A unit quaternions. May be used to represent a rotation.
 pub type UnitQuaternion<N> = Unit<Quaternion<N>>;
 
+impl<N: Scalar + ClosedNeg + PartialEq> PartialEq for UnitQuaternion<N> {
+    #[inline]
+    fn eq(&self, rhs: &Self) -> bool {
+        self.coords == rhs.coords ||
+        // Account for the double-covering of S², i.e. q = -q
+        self.coords.iter().zip(rhs.coords.iter()).all(|(a, b)| *a == -b.inlined_clone())
+    }
+}
+
+impl<N: Scalar + ClosedNeg + Eq> Eq for UnitQuaternion<N> {}
+
 impl<N: SimdRealField> Normed for Quaternion<N> {
     type Norm = N::SimdRealField;
 

src/geometry/quaternion_conversion.rs

@@ -184,14 +184,14 @@ impl<N1: RealField, N2: RealField + SupersetOf<N1>> SubsetOf<Matrix4<N2>> for Un
 }
 
 #[cfg(feature = "mint")]
-impl<N: SimdRealField> From<mint::Quaternion<N>> for Quaternion<N> {
+impl<N: Scalar> From<mint::Quaternion<N>> for Quaternion<N> {
     fn from(q: mint::Quaternion<N>) -> Self {
         Self::new(q.s, q.v.x, q.v.y, q.v.z)
     }
 }
 
 #[cfg(feature = "mint")]
-impl<N: SimdRealField> Into<mint::Quaternion<N>> for Quaternion<N> {
+impl<N: Scalar> Into<mint::Quaternion<N>> for Quaternion<N> {
     fn into(self) -> mint::Quaternion<N> {
         mint::Quaternion {
             v: mint::Vector3 {
@@ -205,7 +205,7 @@ impl<N: SimdRealField> Into<mint::Quaternion<N>> for Quaternion<N> {
 }
 
 #[cfg(feature = "mint")]
-impl<N: SimdRealField> Into<mint::Quaternion<N>> for UnitQuaternion<N> {
+impl<N: Scalar> Into<mint::Quaternion<N>> for UnitQuaternion<N> {
     fn into(self) -> mint::Quaternion<N> {
         mint::Quaternion {
             v: mint::Vector3 {
@@ -258,14 +258,14 @@ where
     }
 }
 
-impl<N: Scalar + SimdValue> From<Vector4<N>> for Quaternion<N> {
+impl<N: Scalar> From<Vector4<N>> for Quaternion<N> {
     #[inline]
     fn from(coords: Vector4<N>) -> Self {
         Self { coords }
     }
 }
 
-impl<N: Scalar + SimdValue> From<[N; 4]> for Quaternion<N> {
+impl<N: Scalar> From<[N; 4]> for Quaternion<N> {
     #[inline]
     fn from(coords: [N; 4]) -> Self {
         Self {

src/geometry/unit_complex.rs

@@ -4,8 +4,10 @@ use std::fmt;
 
 use crate::base::{Matrix2, Matrix3, Normed, Unit, Vector1, Vector2};
 use crate::geometry::{Point2, Rotation2};
+use crate::Scalar;
 use simba::scalar::RealField;
 use simba::simd::SimdRealField;
+use std::cmp::{Eq, PartialEq};
 
 /// A 2D rotation represented as a complex number with magnitude 1.
 ///
@@ -29,6 +31,15 @@ use simba::simd::SimdRealField;
 /// * [Conversion to a matrix <span style="float:right;">`to_rotation_matrix`, `to_homogeneous`…</span>](#conversion-to-a-matrix)
 pub type UnitComplex<N> = Unit<Complex<N>>;
 
+impl<N: Scalar + PartialEq> PartialEq for UnitComplex<N> {
+    #[inline]
+    fn eq(&self, rhs: &Self) -> bool {
+        (**self).eq(&**rhs)
+    }
+}
+
+impl<N: Scalar + Eq> Eq for UnitComplex<N> {}
+
 impl<N: SimdRealField> Normed for Complex<N> {
     type Norm = N::SimdRealField;
 

tests/geometry/quaternion.rs

@@ -114,7 +114,6 @@ quickcheck!(
      */
     fn unit_quaternion_double_covering(q: UnitQuaternion<f64>) -> bool {
         let mq = UnitQuaternion::new_unchecked(-q.into_inner());
-
         mq == q && mq.angle() == q.angle() && mq.axis() == q.axis()
     }