We have reached compilation!

benches/core/matrix.rs

@@ -1,4 +1,7 @@
-use na::{DMatrix, DVector, Matrix2, Matrix3, Matrix4, OMatrix, Vector2, Vector3, Vector4, U10};
+use na::{
+    Const, DMatrix, DVector, Dynamic, Matrix2, Matrix3, Matrix4, OMatrix, Vector2, Vector3,
+    Vector4, U10,
+};
 use rand::Rng;
 use rand_isaac::IsaacRng;
 use std::ops::{Add, Div, Mul, Sub};
@@ -186,7 +189,7 @@ fn axpy(bench: &mut criterion::Criterion) {
 fn tr_mul_to(bench: &mut criterion::Criterion) {
     let a = DMatrix::<f64>::new_random(1000, 1000);
     let b = DVector::<f64>::new_random(1000);
-    let mut c = DVector::from_element(1000, 0.0);
+    let mut c = DVector::new_uninitialized_generic(Dynamic::new(1000), Const::<1>);
 
     bench.bench_function("tr_mul_to", move |bh| bh.iter(|| a.tr_mul_to(&b, &mut c)));
 }
@@ -194,7 +197,7 @@ fn tr_mul_to(bench: &mut criterion::Criterion) {
 fn mat_mul_mat(bench: &mut criterion::Criterion) {
     let a = DMatrix::<f64>::new_random(100, 100);
     let b = DMatrix::<f64>::new_random(100, 100);
-    let mut ab = DMatrix::<f64>::from_element(100, 100, 0.0);
+    let mut ab = DMatrix::new_uninitialized_generic(Dynamic::new(100), Dynamic::new(100));
 
     bench.bench_function("mat_mul_mat", move |bh| {
         bh.iter(|| {

nalgebra-lapack/src/eigen.rs

@@ -78,9 +78,9 @@ where
 
         let lda = n as i32;
 
-        let mut wr = unsafe { Matrix::new_uninitialized_generic(nrows, Const::<1>).assume_init() };
+        let mut wr = unsafe { Matrix::new_uninitialized_generic(nrows, U1).assume_init() };
         // TODO: Tap into the workspace.
-        let mut wi = unsafe { Matrix::new_uninitialized_generic(nrows, Const::<1>).assume_init() };
+        let mut wi = unsafe { Matrix::new_uninitialized_generic(nrows, U1).assume_init() };
 
         let mut info = 0;
         let mut placeholder1 = [T::zero()];
@@ -247,8 +247,8 @@ where
 
         let lda = n as i32;
 
-        let mut wr = unsafe { Matrix::new_uninitialized_generic(nrows, Const::<1>).assume_init() };
+        let mut wr = unsafe { Matrix::new_uninitialized_generic(nrows, U1).assume_init() };
-        let mut wi = unsafe { Matrix::new_uninitialized_generic(nrows, Const::<1>).assume_init() };
+        let mut wi = unsafe { Matrix::new_uninitialized_generic(nrows, U1).assume_init() };
 
         let mut info = 0;
         let mut placeholder1 = [T::zero()];
@@ -291,7 +291,7 @@ where
         );
         lapack_panic!(info);
 
-        let mut res = unsafe { Matrix::new_uninitialized_generic(nrows, Const::<1>).assume_init() };
+        let mut res = unsafe { Matrix::new_uninitialized_generic(nrows, U1).assume_init() };
 
         for i in 0..res.len() {
             res[i] = Complex::new(wr[i], wi[i]);

nalgebra-lapack/src/hessenberg.rs

@@ -61,7 +61,7 @@ where
         );
 
         let mut tau = unsafe {
-            Matrix::new_uninitialized_generic(nrows.sub(Const::<1>), Const::<1>).assume_init()
+            Matrix::new_uninitialized_generic(nrows.sub(U1), U1).assume_init()
         };
 
         let mut info = 0;

nalgebra-lapack/src/lu.rs

@@ -66,7 +66,7 @@ where
         let nrows = nrows.value() as i32;
         let ncols = ncols.value() as i32;
 
-        let mut ipiv: OVector<i32, _> = Matrix::zeros_generic(min_nrows_ncols, Const::<1>);
+        let mut ipiv: OVector<i32, _> = Matrix::zeros_generic(min_nrows_ncols, U1);
 
         let mut info = 0;
 

nalgebra-lapack/src/qr.rs

@@ -58,7 +58,7 @@ where
 
         let mut info = 0;
         let mut tau = unsafe {
-            Matrix::new_uninitialized_generic(nrows.min(ncols), Const::<1>).assume_init()
+            Matrix::new_uninitialized_generic(nrows.min(ncols), U1).assume_init()
         };
 
         if nrows.value() == 0 || ncols.value() == 0 {

nalgebra-lapack/src/schur.rs

@@ -78,8 +78,8 @@ where
 
         let mut info = 0;
 
-        let mut wr = unsafe { Matrix::new_uninitialized_generic(nrows, Const::<1>).assume_init() };
+        let mut wr = unsafe { Matrix::new_uninitialized_generic(nrows, U1).assume_init() };
-        let mut wi = unsafe { Matrix::new_uninitialized_generic(nrows, Const::<1>).assume_init() };
+        let mut wi = unsafe { Matrix::new_uninitialized_generic(nrows, U1).assume_init() };
         let mut q = unsafe { Matrix::new_uninitialized_generic(nrows, ncols).assume_init() };
         // Placeholders:
         let mut bwork = [0i32];
@@ -154,7 +154,7 @@ where
         DefaultAllocator: Allocator<Complex<T>, D>,
     {
         let mut out =
-            unsafe { OVector::new_uninitialized_generic(self.t.data.shape().0, Const::<1>) };
+            unsafe { OVector::new_uninitialized_generic(self.t.data.shape().0, U1) };
 
         for i in 0..out.len() {
             out[i] = MaybeUninit::new(Complex::new(self.re[i], self.im[i]));

nalgebra-lapack/src/svd.rs

@@ -100,7 +100,7 @@ macro_rules! svd_impl(
                 let lda = nrows.value() as i32;
 
                 let mut u  = unsafe { Matrix::new_uninitialized_generic(nrows, nrows).assume_init() };
-                let mut s  = unsafe { Matrix::new_uninitialized_generic(nrows.min(ncols), Const::<1>).assume_init() };
+                let mut s  = unsafe { Matrix::new_uninitialized_generic(nrows.min(ncols), U1).assume_init() };
                 let mut vt = unsafe { Matrix::new_uninitialized_generic(ncols, ncols).assume_init() };
 
                 let ldu  = nrows.value();

nalgebra-lapack/src/symmetric_eigen.rs

@@ -95,7 +95,7 @@ where
         let lda = n as i32;
 
         let mut values =
-            unsafe { Matrix::new_uninitialized_generic(nrows, Const::<1>).assume_init() };
+            unsafe { Matrix::new_uninitialized_generic(nrows, U1).assume_init() };
         let mut info = 0;
 
         let lwork = T::xsyev_work_size(jobz, b'L', n as i32, m.as_mut_slice(), lda, &mut info);

nalgebra-sparse/src/convert/impl_std_ops.rs

@@ -8,7 +8,7 @@ use num_traits::Zero;
 
 impl<'a, T, R: Dim, C: Dim, S> From<&'a Matrix<T, R, C, S>> for CooMatrix<T>
 where
-    T: Scalar + Zero,
+    T: Scalar + Zero + PartialEq,
     S: Storage<T, R, C>,
 {
     fn from(matrix: &'a Matrix<T, R, C, S>) -> Self {
@@ -45,7 +45,7 @@ where
 
 impl<'a, T, R: Dim, C: Dim, S> From<&'a Matrix<T, R, C, S>> for CsrMatrix<T>
 where
-    T: Scalar + Zero,
+    T: Scalar + Zero + PartialEq,
     S: Storage<T, R, C>,
 {
     fn from(matrix: &'a Matrix<T, R, C, S>) -> Self {
@@ -82,7 +82,7 @@ where
 
 impl<'a, T, R: Dim, C: Dim, S> From<&'a Matrix<T, R, C, S>> for CscMatrix<T>
 where
-    T: Scalar + Zero,
+    T: Scalar + Zero + PartialEq,
     S: Storage<T, R, C>,
 {
     fn from(matrix: &'a Matrix<T, R, C, S>) -> Self {

nalgebra-sparse/src/convert/serial.rs

@@ -16,11 +16,9 @@ use crate::csc::CscMatrix;
 use crate::csr::CsrMatrix;
 
 /// Converts a dense matrix to [`CooMatrix`].
-pub fn convert_dense_coo<T, R, C, S>(dense: &Matrix<T, R, C, S>) -> CooMatrix<T>
+pub fn convert_dense_coo<T, R: Dim, C: Dim, S>(dense: &Matrix<T, R, C, S>) -> CooMatrix<T>
 where
-    T: Scalar + Zero,
+    T: Scalar + Zero + PartialEq,
-    R: Dim,
-    C: Dim,
     S: Storage<T, R, C>,
 {
     let mut coo = CooMatrix::new(dense.nrows(), dense.ncols());
@@ -93,7 +91,7 @@ where
 /// Converts a dense matrix to a [`CsrMatrix`].
 pub fn convert_dense_csr<T, R, C, S>(dense: &Matrix<T, R, C, S>) -> CsrMatrix<T>
 where
-    T: Scalar + Zero,
+    T: Scalar + Zero + PartialEq,
     R: Dim,
     C: Dim,
     S: Storage<T, R, C>,
@@ -170,7 +168,7 @@ where
 /// Converts a dense matrix to a [`CscMatrix`].
 pub fn convert_dense_csc<T, R, C, S>(dense: &Matrix<T, R, C, S>) -> CscMatrix<T>
 where
-    T: Scalar + Zero,
+    T: Scalar + Zero + PartialEq,
     R: Dim,
     C: Dim,
     S: Storage<T, R, C>,

nalgebra-sparse/src/ops/impl_std_ops.rs

@@ -6,7 +6,7 @@ use crate::ops::serial::{
     spmm_csc_prealloc, spmm_csr_dense, spmm_csr_pattern, spmm_csr_prealloc,
 };
 use crate::ops::Op;
-use nalgebra::allocator::Allocator;
+use nalgebra::allocator::{Allocator, InnerAllocator};
 use nalgebra::base::storage::Storage;
 use nalgebra::constraint::{DimEq, ShapeConstraint};
 use nalgebra::{
@@ -28,7 +28,7 @@ macro_rules! impl_bin_op {
             // Note: The Neg bound is currently required because we delegate e.g.
             // Sub to SpAdd with negative coefficients. This is not well-defined for
             // unsigned data types.
-            $($scalar_type: $($bounds + )? Scalar + ClosedAdd + ClosedSub + ClosedMul + Zero + One + Neg<Output=T>)?
+            $($scalar_type: $($bounds + )? Scalar + ClosedAdd + ClosedSub + ClosedMul + Zero + One + Neg<Output=T> + PartialEq)?
         {
             type Output = $ret;
             fn $method(self, $b: $b_type) -> Self::Output {
@@ -306,9 +306,9 @@ macro_rules! impl_spmm_cs_dense {
             // TODO: Is it possible to simplify these bounds?
             ShapeConstraint:
                 // Bounds so that we can turn OMatrix<T, Dynamic, C> into a DMatrixSliceMut
-                  DimEq<U1, <<DefaultAllocator as Allocator<T, Dynamic, C>>::Buffer as Storage<T, Dynamic, C>>::RStride>
+                  DimEq<U1, <<DefaultAllocator as InnerAllocator<T, Dynamic, C>>::Buffer as Storage<T, Dynamic, C>>::RStride>
                 + DimEq<C, Dynamic>
-                + DimEq<Dynamic, <<DefaultAllocator as Allocator<T, Dynamic, C>>::Buffer as Storage<T, Dynamic, C>>::CStride>
+                + DimEq<Dynamic, <<DefaultAllocator as InnerAllocator<T, Dynamic, C>>::Buffer as Storage<T, Dynamic, C>>::CStride>
                 // Bounds so that we can turn &Matrix<T, R, C, S> into a DMatrixSlice
                 + DimEq<U1, S::RStride>
                 + DimEq<R, Dynamic>

nalgebra-sparse/src/ops/serial/cs.rs

@@ -74,7 +74,7 @@ pub fn spadd_cs_prealloc<T>(
     a: Op<&CsMatrix<T>>,
 ) -> Result<(), OperationError>
 where
-    T: Scalar + ClosedAdd + ClosedMul + Zero + One,
+    T: Scalar + ClosedAdd + ClosedMul + Zero + One+PartialEq,
 {
     match a {
         Op::NoOp(a) => {

nalgebra-sparse/src/ops/serial/csc.rs

@@ -55,7 +55,7 @@ pub fn spadd_csc_prealloc<T>(
     a: Op<&CscMatrix<T>>,
 ) -> Result<(), OperationError>
 where
-    T: Scalar + ClosedAdd + ClosedMul + Zero + One,
+    T: Scalar + ClosedAdd + ClosedMul + Zero + One+PartialEq,
 {
     assert_compatible_spadd_dims!(c, a);
     spadd_cs_prealloc(beta, &mut c.cs, alpha, a.map_same_op(|a| &a.cs))

nalgebra-sparse/src/ops/serial/csr.rs

@@ -50,7 +50,7 @@ pub fn spadd_csr_prealloc<T>(
     a: Op<&CsrMatrix<T>>,
 ) -> Result<(), OperationError>
 where
-    T: Scalar + ClosedAdd + ClosedMul + Zero + One,
+    T: Scalar + ClosedAdd + ClosedMul + Zero + One + PartialEq,
 {
     assert_compatible_spadd_dims!(c, a);
     spadd_cs_prealloc(beta, &mut c.cs, alpha, a.map_same_op(|a| &a.cs))

src/base/allocator.rs

@@ -1,6 +1,6 @@
 //! Abstract definition of a matrix data storage allocator.
 
-use std::mem::MaybeUninit;
+use std::mem::{ManuallyDrop, MaybeUninit};
 
 use crate::base::constraint::{SameNumberOfColumns, SameNumberOfRows, ShapeConstraint};
 use crate::base::dimension::{Dim, U1};
@@ -30,9 +30,12 @@ pub trait InnerAllocator<T, R: Dim, C: Dim = U1>: 'static + Sized {
     ) -> Self::Buffer;
 }
 
-/// Same as the [`InnerAllocator`] trait, but also provides methods to build uninitialized buffers.
+/// Same as the [`InnerAllocator`] trait, but also provides methods to build uninitialized buffers,
+/// or buffers whose entries must be manually dropped.
 pub trait Allocator<T, R: Dim, C: Dim = U1>:
-    InnerAllocator<T, R, C> + InnerAllocator<MaybeUninit<T>, R, C>
+    InnerAllocator<T, R, C>
+    + InnerAllocator<MaybeUninit<T>, R, C>
+    + InnerAllocator<ManuallyDrop<T>, R, C>
 {
     /// Allocates a buffer with the given number of rows and columns without initializing its content.
     fn allocate_uninitialized(
@@ -44,6 +47,11 @@ pub trait Allocator<T, R: Dim, C: Dim = U1>:
     unsafe fn assume_init(
         uninit: <Self as InnerAllocator<MaybeUninit<T>, R, C>>::Buffer,
     ) -> <Self as InnerAllocator<T, R, C>>::Buffer;
+
+    /// Specifies that a given buffer's entries should be manually dropped.
+    fn manually_drop(
+        buf: <Self as InnerAllocator<T, R, C>>::Buffer,
+    ) -> <Self as InnerAllocator<ManuallyDrop<T>, R, C>>::Buffer;
 }
 
 /// A matrix reallocator. Changes the size of the memory buffer that initially contains (RFrom ×
@@ -84,8 +92,7 @@ where
 impl<T, R1: Dim, R2: Dim, C1: Dim, C2: Dim> SameShapeAllocator<T, R1, C1, R2, C2>
     for DefaultAllocator
 where
-    DefaultAllocator:
+    DefaultAllocator: Allocator<T, R1, C1> + Allocator<T, SameShapeR<R1, R2>, SameShapeC<C1, C2>>,
-        Allocator<T, R1, C1> + Allocator<T, SameShapeR<R1, R2>, SameShapeC<C1, C2>>,
     ShapeConstraint: SameNumberOfRows<R1, R2> + SameNumberOfColumns<C1, C2>,
 {
 }
@@ -93,9 +100,7 @@ where
 // XXX: Bad name.
 /// Restricts the given number of rows to be equal.
 pub trait SameShapeVectorAllocator<T, R1: Dim, R2: Dim>:
-    Allocator<T, R1>
+    Allocator<T, R1> + Allocator<T, SameShapeR<R1, R2>> + SameShapeAllocator<T, R1, U1, R2, U1>
-    + Allocator<T, SameShapeR<R1, R2>>
-    + SameShapeAllocator<T, R1, U1, R2, U1>
 where
     ShapeConstraint: SameNumberOfRows<R1, R2>,
 {

src/base/blas.rs

@@ -329,22 +329,18 @@ where
 
             if !b.is_zero() {
                 for i in 0..x.len() {
-                    
                     let y = y.get_unchecked_mut(i * rstride1);
                     *y = a.inlined_clone()
                         * x.get_unchecked(i * rstride2).inlined_clone()
                         * c.inlined_clone()
                         + b.inlined_clone() * y.inlined_clone();
-                    
                 }
             } else {
                 for i in 0..x.len() {
-                    
                     let y = y.get_unchecked_mut(i * rstride1);
                     *y = a.inlined_clone()
                         * x.get_unchecked(i * rstride2).inlined_clone()
                         * c.inlined_clone();
-                    
                 }
             }
         }
@@ -852,6 +848,8 @@ where
         }
     }
 
+    /// Computes `self = alpha * a * x`, where `a` is an **hermitian** matrix, `x` a
+    /// vector, and `alpha, beta` two scalars.
     pub fn hegemv_z<D2: Dim, D3: Dim, SB, SC>(
         &mut self,
         alpha: T,
@@ -1574,7 +1572,8 @@ where
         ShapeConstraint: DimEq<D1, R3> + DimEq<C3, D4>,
         DefaultAllocator: Allocator<T, R3>,
     {
-        let mut work = Matrix::new_uninitialized_generic(R3::from_usize(self.shape().0), Const::<1>);
+        let mut work =
+            Matrix::new_uninitialized_generic(R3::from_usize(self.shape().0), Const::<1>);
         work.gemv_z(T::one(), lhs, &mid.column(0));
         let mut work = unsafe { work.assume_init() };
 
@@ -1624,7 +1623,8 @@ where
         DefaultAllocator: Allocator<T, D3>,
     {
         // TODO: figure out why type inference wasn't doing its job.
-        let mut work = Matrix::new_uninitialized_generic(D3::from_usize(self.shape().0), Const::<1>);
+        let mut work =
+            Matrix::new_uninitialized_generic(D3::from_usize(self.shape().0), Const::<1>);
         work.gemv_z::<D3, D3, R4, S3, _>(T::one(), mid, &rhs.column(0));
         let mut work = unsafe { work.assume_init() };
 

src/base/conversion.rs

@@ -361,7 +361,7 @@ where
     }
 }
 
-impl<'a, T: Dim, R: Dim, C: Dim, RSlice: Dim, CSlice: Dim, RStride: Dim, CStride: Dim, S>
+impl<'a, T, R: Dim, C: Dim, RSlice: Dim, CSlice: Dim, RStride: Dim, CStride: Dim, S>
     From<&'a mut Matrix<T, R, C, S>> for MatrixSliceMut<'a, T, RSlice, CSlice, RStride, CStride>
 where
     S: StorageMut<T, R, C>,

src/base/default_allocator.rs

@@ -4,8 +4,7 @@
 //! heap-allocated buffers for matrices with at least one dimension unknown at compile-time.
 
 use std::cmp;
-use std::mem::ManuallyDrop;
+use std::mem::{self, ManuallyDrop, MaybeUninit};
-use std::mem::MaybeUninit;
 use std::ptr;
 
 #[cfg(all(feature = "alloc", not(feature = "std")))]
@@ -22,10 +21,6 @@ use crate::base::storage::{ContiguousStorageMut, Storage, StorageMut};
 use crate::base::vec_storage::VecStorage;
 use crate::storage::Owned;
 
-type DefaultBuffer<T, R, C> = <DefaultAllocator as InnerAllocator<T, R, C>>::Buffer;
-type DefaultUninitBuffer<T, R, C> =
-    <DefaultAllocator as InnerAllocator<MaybeUninit<T>, R, C>>::Buffer;
-
 /*
  *
  * Allocator.
@@ -72,7 +67,7 @@ impl<T, const R: usize, const C: usize> Allocator<T, Const<R>, Const<C>> for Def
         _: Const<R>,
         _: Const<C>,
     ) -> Owned<MaybeUninit<T>, Const<R>, Const<C>> {
-        // SAFETY: An uninitialized `[MaybeUninit<_>; LEN]` is valid.
+        // SAFETY: An uninitialized `[MaybeUninit<_>; _]` is valid.
         let array = unsafe { MaybeUninit::uninit().assume_init() };
         ArrayStorage(array)
     }
@@ -84,11 +79,24 @@ impl<T, const R: usize, const C: usize> Allocator<T, Const<R>, Const<C>> for Def
         // SAFETY:
         // * The caller guarantees that all elements of the array are initialized
         // * `MaybeUninit<T>` and T are guaranteed to have the same layout
-        // * MaybeUnint does not drop, so there are no double-frees
+        // * `MaybeUnint` does not drop, so there are no double-frees
         // * `ArrayStorage` is transparent.
         // And thus the conversion is safe
         ArrayStorage((&uninit as *const _ as *const [_; C]).read())
     }
+
+    /// Specifies that a given buffer's entries should be manually dropped.
+    #[inline]
+    fn manually_drop(
+        buf: <Self as InnerAllocator<T, Const<R>, Const<C>>>::Buffer,
+    ) -> <Self as InnerAllocator<ManuallyDrop<T>, Const<R>, Const<C>>>::Buffer {
+        // SAFETY:
+        // * `ManuallyDrop<T>` and T are guaranteed to have the same layout
+        // * `ManuallyDrop` does not drop, so there are no double-frees
+        // * `ArrayStorage` is transparent.
+        // And thus the conversion is safe
+        ArrayStorage(unsafe { mem::transmute_copy(&ManuallyDrop::new(buf.0)) })
+    }
 }
 
 // Dynamic - Static
@@ -133,6 +141,25 @@ impl<T, C: Dim> Allocator<T, Dynamic, C> for DefaultAllocator {
 
         VecStorage::new(uninit.nrows, uninit.ncols, new_data)
     }
+
+    #[inline]
+    fn manually_drop(
+        buf: <Self as InnerAllocator<T, Dynamic, C>>::Buffer,
+    ) -> <Self as InnerAllocator<ManuallyDrop<T>, Dynamic, C>>::Buffer {
+        // Avoids dropping the buffer that will be used for the result.
+        let mut data = ManuallyDrop::new(buf.data);
+
+        // Safety: ManuallyDrop<T> has the same alignment and layout as T.
+        let new_data = unsafe {
+            Vec::from_raw_parts(
+                data.as_mut_ptr() as *mut ManuallyDrop<T>,
+                data.len(),
+                data.capacity(),
+            )
+        };
+
+        VecStorage::new(buf.nrows, buf.ncols, new_data)
+    }
 }
 
 // Static - Dynamic
@@ -176,6 +203,25 @@ impl<T, R: DimName> Allocator<T, R, Dynamic> for DefaultAllocator {
 
         VecStorage::new(uninit.nrows, uninit.ncols, new_data)
     }
+
+    #[inline]
+    fn manually_drop(
+        buf: <Self as InnerAllocator<T, R, Dynamic>>::Buffer,
+    ) -> <Self as InnerAllocator<ManuallyDrop<T>, R, Dynamic>>::Buffer {
+        // Avoids dropping the buffer that will be used for the result.
+        let mut data = ManuallyDrop::new(buf.data);
+
+        // Safety: ManuallyDrop<T> has the same alignment and layout as T.
+        let new_data = unsafe {
+            Vec::from_raw_parts(
+                data.as_mut_ptr() as *mut ManuallyDrop<T>,
+                data.len(),
+                data.capacity(),
+            )
+        };
+
+        VecStorage::new(buf.nrows, buf.ncols, new_data)
+    }
 }
 
 /*

src/base/matrix.rs

@@ -8,7 +8,7 @@ use std::cmp::Ordering;
 use std::fmt;
 use std::hash::{Hash, Hasher};
 use std::marker::PhantomData;
-use std::mem::{self, MaybeUninit};
+use std::mem::{self, ManuallyDrop, MaybeUninit};
 
 #[cfg(feature = "serde-serialize-no-std")]
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
@@ -194,10 +194,7 @@ pub struct Matrix<T, R, C, S> {
 
 impl<T, R: Dim, C: Dim, S: Default> Default for Matrix<T, R, C, S> {
     fn default() -> Self {
-        Matrix {
+        unsafe { Matrix::from_data_statically_unchecked(Default::default()) }
-            data: Default::default(),
-            _phantoms: PhantomData,
-        }
     }
 }
 
@@ -212,7 +209,7 @@ impl<T, R: Dim, C: Dim, S: Serialize> Serialize for Matrix<T, R, C, S> {
 }
 
 #[cfg(feature = "serde-serialize-no-std")]
-impl<'de, T: Dim, R: Dim, C, S: Serialize<'de>> Deserialize<'de> for Matrix<T, R, C, S> {
+impl<'de, T, R: Dim, C, S: Serialize<'de>> Deserialize<'de> for Matrix<T, R, C, S> {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
         D: Deserializer<'de>,
@@ -344,9 +341,20 @@ where
 {
     /// Allocates a matrix with the given number of rows and columns without initializing its content.
     pub fn new_uninitialized_generic(nrows: R, ncols: C) -> OMatrix<MaybeUninit<T>, R, C> {
-        OMatrix {
+        unsafe {
-            data: <DefaultAllocator as Allocator<T, R, C>>::allocate_uninitialized(nrows, ncols),
+            OMatrix::from_data_statically_unchecked(
-            _phantoms: PhantomData,
+                <DefaultAllocator as Allocator<T, R, C>>::allocate_uninitialized(nrows, ncols),
+            )
+        }
+    }
+
+    /// Converts this matrix into one whose entries need to be manually dropped. This should be
+    /// near zero-cost.
+    pub fn manually_drop(self) -> OMatrix<ManuallyDrop<T>, R, C> {
+        unsafe {
+            OMatrix::from_data_statically_unchecked(
+                <DefaultAllocator as Allocator<T, R, C>>::manually_drop(self.data),
+            )
         }
     }
 }
@@ -356,11 +364,12 @@ where
     DefaultAllocator: Allocator<T, R, C>,
 {
     /// Assumes a matrix's entries to be initialized. This operation should be near zero-cost.
+    ///
+    /// For the similar method that operates on matrix slices, see [`slice_assume_init`].
     pub unsafe fn assume_init(self) -> OMatrix<T, R, C> {
-        OMatrix {
+        OMatrix::from_data_statically_unchecked(
-            data: <DefaultAllocator as Allocator<T, R, C>>::assume_init(self.data),
+            <DefaultAllocator as Allocator<T, R, C>>::assume_init(self.data),
-            _phantoms: PhantomData,
+        )
-        }
     }
 }
 
@@ -711,30 +720,35 @@ impl<T, R: Dim, C: Dim, S: Storage<T, R, C>> Matrix<T, R, C, S> {
             res.assume_init()
         }
     }
+}
 
-    /// Transposes `self`. Does not require `T: Clone` like its other counteparts.
+impl<T, R: Dim, C: Dim> OMatrix<T, R, C>
-    pub fn transpose_into(self) -> OMatrix<T, C, R>
 where
-        DefaultAllocator: Allocator<T, C, R>,
+    DefaultAllocator: Allocator<T, C, R> + Allocator<T, R, C>,
 {
+    /// Transposes `self`. Does not require `T: Clone` like its other counterparts.
+    pub fn transpose_into(self) -> OMatrix<T, C, R> {
         let (nrows, ncols) = self.data.shape();
         let mut res = OMatrix::new_uninitialized_generic(ncols, nrows);
+        let mut md = self.manually_drop();
 
         let (nrows, ncols) = res.shape();
 
         // TODO: optimize that.
         for i in 0..nrows {
             for j in 0..ncols {
+                // Safety: the indices are within range, and since the indices
+                // don't repeat, we don't do any double-drops.
                 unsafe {
-                    *res.get_unchecked_mut((j, i)) = MaybeUninit::new(*self.get_unchecked((i, j)));
+                    *res.get_unchecked_mut((j, i)) =
+                        MaybeUninit::new(ManuallyDrop::take(md.get_unchecked_mut((i, j))));
                 }
             }
         }
 
-        // BEEP! BEEP! There's a double drop here that needs to be fixed.
-
         unsafe {
-            // Safety: res is now fully initialized due to the guarantees of transpose_to.
+            // Safety: res is now fully initialized, since we've initialized
+            // every single entry.
             res.assume_init()
         }
     }
@@ -956,7 +970,6 @@ impl<T, R: Dim, C: Dim, S: Storage<T, R, C>> Matrix<T, R, C, S> {
         ShapeConstraint: SameNumberOfRows<R, R2> + SameNumberOfColumns<C, C2>,
     {
         let (nrows, ncols) = self.data.shape();
-
         let mut res = init;
 
         assert_eq!(
@@ -982,6 +995,7 @@ impl<T, R: Dim, C: Dim, S: Storage<T, R, C>> Matrix<T, R, C, S> {
     #[inline]
     pub fn apply<F: FnMut(T) -> T>(&mut self, mut f: F)
     where
+        T: Clone, // This could be removed by changing the function signature.
         S: StorageMut<T, R, C>,
     {
         let (nrows, ncols) = self.shape();
@@ -990,7 +1004,7 @@ impl<T, R: Dim, C: Dim, S: Storage<T, R, C>> Matrix<T, R, C, S> {
             for i in 0..nrows {
                 unsafe {
                     let e = self.data.get_unchecked_mut(i, j);
-                    *e = f(*e)
+                    *e = f(e.clone())
                 }
             }
         }
@@ -1004,6 +1018,7 @@ impl<T, R: Dim, C: Dim, S: Storage<T, R, C>> Matrix<T, R, C, S> {
         rhs: &Matrix<T2, R2, C2, S2>,
         mut f: impl FnMut(T, T2) -> T,
     ) where
+        T: Clone, // This could be removed by changing the function signature.
         S: StorageMut<T, R, C>,
         S2: Storage<T2, R2, C2>,
         ShapeConstraint: SameNumberOfRows<R, R2> + SameNumberOfColumns<C, C2>,
@@ -1021,7 +1036,7 @@ impl<T, R: Dim, C: Dim, S: Storage<T, R, C>> Matrix<T, R, C, S> {
                 unsafe {
                     let e = self.data.get_unchecked_mut(i, j);
                     let rhs = rhs.get_unchecked((i, j)).clone();
-                    *e = f(*e, rhs)
+                    *e = f(e.clone(), rhs)
                 }
             }
         }
@@ -1036,6 +1051,7 @@ impl<T, R: Dim, C: Dim, S: Storage<T, R, C>> Matrix<T, R, C, S> {
         c: &Matrix<N3, R3, C3, S3>,
         mut f: impl FnMut(T, T2, N3) -> T,
     ) where
+        T: Clone, // This could be removed by changing the function signature.
         S: StorageMut<T, R, C>,
         S2: Storage<T2, R2, C2>,
         S3: Storage<N3, R3, C3>,
@@ -1061,7 +1077,7 @@ impl<T, R: Dim, C: Dim, S: Storage<T, R, C>> Matrix<T, R, C, S> {
                     let e = self.data.get_unchecked_mut(i, j);
                     let b = b.get_unchecked((i, j)).clone();
                     let c = c.get_unchecked((i, j)).clone();
-                    *e = f(*e, b, c)
+                    *e = f(e.clone(), b, c)
                 }
             }
         }
@@ -1249,8 +1265,11 @@ impl<T, R: Dim, C: Dim, S: StorageMut<T, R, C>> Matrix<T, R, C, S> {
     /// Fills this matrix with the content of another one, after applying a function to
     /// the references of the entries of the other matrix. Both must have the same shape.
     #[inline]
-    pub fn copy_from_fn<U, R2: Dim, C2: Dim, SB, F>(&mut self, other: &Matrix<U, R2, C2, SB>,mut f: F)
+    pub fn copy_from_fn<U, R2: Dim, C2: Dim, SB, F>(
-    where
+        &mut self,
+        other: &Matrix<U, R2, C2, SB>,
+        mut f: F,
+    ) where
         SB: Storage<U, R2, C2>,
         ShapeConstraint: SameNumberOfRows<R, R2> + SameNumberOfColumns<C, C2>,
         F: FnMut(&U) -> T,
@@ -1272,20 +1291,20 @@ impl<T, R: Dim, C: Dim, S: StorageMut<T, R, C>> Matrix<T, R, C, S> {
     /// Fills this matrix with the content of another one, after applying a function to
     /// the entries of the other matrix. Both must have the same shape.
     #[inline]
-    pub fn move_from<R2: Dim, C2: Dim, SB>(&mut self, other: Matrix<T, R2, C2, SB>)
+    pub fn move_from<R2: Dim, C2: Dim>(&mut self, other: OMatrix<T, R2, C2>)
     where
-        SB: Storage<T, R2, C2>,
         ShapeConstraint: SameNumberOfRows<R, R2> + SameNumberOfColumns<C, C2>,
+        DefaultAllocator: Allocator<T, R2, C2>,
     {
         self.move_from_fn(other, |e| e)
     }
 
     /// Fills this matrix with the content of another one via moves. Both must have the same shape.
     #[inline]
-    pub fn move_from_fn<U, R2: Dim, C2: Dim, SB, F>(&mut self, other: Matrix<U, R2, C2, SB>, mut f: F)
+    pub fn move_from_fn<U, R2: Dim, C2: Dim, F>(&mut self, other: OMatrix<U, R2, C2>, mut f: F)
     where
-        SB: Storage<U, R2, C2>,
         ShapeConstraint: SameNumberOfRows<R, R2> + SameNumberOfColumns<C, C2>,
+        DefaultAllocator: Allocator<U, R2, C2>,
         F: FnMut(U) -> T,
     {
         assert!(
@@ -1293,15 +1312,16 @@ impl<T, R: Dim, C: Dim, S: StorageMut<T, R, C>> Matrix<T, R, C, S> {
             "Unable to move from a matrix with a different shape."
         );
 
+        let mut md = other.manually_drop();
+
         for j in 0..self.ncols() {
             for i in 0..self.nrows() {
                 unsafe {
-                    *self.get_unchecked_mut((i, j)) = f(*other.get_unchecked((i, j)));
+                    *self.get_unchecked_mut((i, j)) =
+                        f(ManuallyDrop::take(md.get_unchecked_mut((i, j))));
                 }
             }
         }
-
-        // BEEP BEEEP!!!!! I'm double-freeing! OH NO!!!! (todo)
     }
 
     /// Fills this matrix with the content of the transpose another one via clones.
@@ -1345,9 +1365,9 @@ impl<T, R: Dim, C: Dim, S: StorageMut<T, R, C>> Matrix<T, R, C, S> {
 
     /// Fills this matrix with the content of the transpose another one via moves.
     #[inline]
-    pub fn tr_move_from<R2: Dim, C2: Dim, SB>(&mut self, other: Matrix<T, R2, C2, SB>)
+    pub fn tr_move_from<R2: Dim, C2: Dim>(&mut self, other: OMatrix<T, R2, C2>)
     where
-        SB: Storage<T, R2, C2>,
+        DefaultAllocator: Allocator<T, R2, C2>,
         ShapeConstraint: DimEq<R, C2> + SameNumberOfColumns<C, R2>,
     {
         self.tr_move_from_fn(other, |e| e)
@@ -1356,13 +1376,10 @@ impl<T, R: Dim, C: Dim, S: StorageMut<T, R, C>> Matrix<T, R, C, S> {
     /// Fills this matrix with the content of the transpose of another one, after applying
     /// a function to the entries of the other matrix. Both must have the same shape.
     #[inline]
-    pub fn tr_move_from_fn<U, R2: Dim, C2: Dim, SB, F>(
+    pub fn tr_move_from_fn<U, R2: Dim, C2: Dim, F>(&mut self, other: OMatrix<U, R2, C2>, mut f: F)
-        &mut self,
+    where
-        other: Matrix<U, R2, C2, SB>,
-      mut  f: F,
-    ) where
-        SB: Storage<U, R2, C2>,
         ShapeConstraint: DimEq<R, C2> + SameNumberOfColumns<C, R2>,
+        DefaultAllocator: Allocator<U, R2, C2>,
         F: FnMut(U) -> T,
     {
         let (nrows, ncols) = self.shape();
@@ -1371,21 +1388,25 @@ impl<T, R: Dim, C: Dim, S: StorageMut<T, R, C>> Matrix<T, R, C, S> {
             "Unable to move from a matrix with incompatible shape."
         );
 
+        let mut md = other.manually_drop();
+
         for j in 0..ncols {
             for i in 0..nrows {
                 unsafe {
-                    *self.get_unchecked_mut((i, j)) = f(*other.get_unchecked((j, i)));
+                    *self.get_unchecked_mut((i, j)) =
+                        f(ManuallyDrop::take(md.get_unchecked_mut((j, i))));
                 }
             }
         }
-
-        // BEEP BEEPP! Same thing as the non-transpose method, this is UB.
     }
 
     // TODO: rename `apply` to `apply_mut` and `apply_into` to `apply`?
     /// Returns `self` with each of its components replaced by the result of a closure `f` applied on it.
     #[inline]
-    pub fn apply_into<F: FnMut(T) -> T>(mut self, f: F) -> Self {
+    pub fn apply_into<F: FnMut(T) -> T>(mut self, f: F) -> Self
+    where
+        T: Clone,
+    {
         self.apply(f);
         self
     }
@@ -1406,9 +1427,10 @@ impl<T, R: Dim, C: Dim, S: StorageMut<MaybeUninit<T>, R, C>> Matrix<MaybeUninit<
     /// Initializes this matrix with the content of another one, after applying a function to
     /// the entries of the other matrix. Both must have the same shape.
     #[inline]
-    pub fn move_init_from<R2: Dim, C2: Dim, SB>(&mut self, other: Matrix<T, R2, C2, SB>)
+    pub fn move_init_from<R2: Dim, C2: Dim, SB>(&mut self, other: OMatrix<T, R2, C2>)
     where
         SB: Storage<T, R2, C2>,
+        DefaultAllocator: Allocator<T, R2, C2>,
         ShapeConstraint: SameNumberOfRows<R, R2> + SameNumberOfColumns<C, C2>,
     {
         self.move_from_fn(other, MaybeUninit::new)
@@ -1427,9 +1449,9 @@ impl<T, R: Dim, C: Dim, S: StorageMut<MaybeUninit<T>, R, C>> Matrix<MaybeUninit<
 
     /// Initializes this matrix with the content of the transpose another one via moves.
     #[inline]
-    pub fn tr_move_init_from<R2: Dim, C2: Dim, SB>(&mut self, other: Matrix<T, R2, C2, SB>)
+    pub fn tr_move_init_from<R2: Dim, C2: Dim>(&mut self, other: OMatrix<T, R2, C2>)
     where
-        SB: Storage<T, R2, C2>,
+        DefaultAllocator: Allocator<T, R2, C2>,
         ShapeConstraint: DimEq<R, C2> + SameNumberOfColumns<C, R2>,
     {
         self.tr_move_from_fn(other, MaybeUninit::new)

src/base/matrix_slice.rs

@@ -222,6 +222,7 @@ storage_impl!(SliceStorage, SliceStorageMut);
 impl<'a, T, R: Dim, C: Dim, RStride: Dim, CStride: Dim>
     SliceStorage<'a, MaybeUninit<T>, R, C, RStride, CStride>
 {
+    /// Assumes a slice storage's entries to be initialized. This operation should be near zero-cost.
     pub unsafe fn assume_init(self) -> SliceStorage<'a, T, R, C, RStride, CStride> {
         SliceStorage::from_raw_parts(self.ptr as *const T, self.shape, self.strides)
     }
@@ -230,6 +231,7 @@ impl<'a, T, R: Dim, C: Dim, RStride: Dim, CStride: Dim>
 impl<'a, T, R: Dim, C: Dim, RStride: Dim, CStride: Dim>
     SliceStorageMut<'a, MaybeUninit<T>, R, C, RStride, CStride>
 {
+    /// Assumes a slice storage's entries to be initialized. This operation should be near zero-cost.
     pub unsafe fn assume_init(self) -> SliceStorageMut<'a, T, R, C, RStride, CStride> {
         SliceStorageMut::from_raw_parts(self.ptr as *mut T, self.shape, self.strides)
     }
@@ -760,6 +762,7 @@ impl<T, R: Dim, C: Dim, S: StorageMut<T, R, C>> Matrix<T, R, C, S> {
 impl<'a, T, R: Dim, C: Dim, RStride: Dim, CStride: Dim>
     MatrixSlice<'a, MaybeUninit<T>, R, C, RStride, CStride>
 {
+    /// Assumes a matrix slices's entries to be initialized. This operation should be near zero-cost.
     pub unsafe fn slice_assume_init(self) -> MatrixSlice<'a, T, R, C, RStride, CStride> {
         Matrix::from_data(self.data.assume_init())
     }
@@ -768,6 +771,7 @@ impl<'a, T, R: Dim, C: Dim, RStride: Dim, CStride: Dim>
 impl<'a, T, R: Dim, C: Dim, RStride: Dim, CStride: Dim>
     MatrixSliceMut<'a, MaybeUninit<T>, R, C, RStride, CStride>
 {
+    /// Assumes a matrix slices's entries to be initialized. This operation should be near zero-cost.
     pub unsafe fn slice_assume_init(self) -> MatrixSliceMut<'a, T, R, C, RStride, CStride> {
         Matrix::from_data(self.data.assume_init())
     }

src/debug/random_orthogonal.rs

@@ -1,3 +1,5 @@
+use std::fmt;
+
 #[cfg(feature = "arbitrary")]
 use crate::base::storage::Owned;
 #[cfg(feature = "arbitrary")]
@@ -5,20 +7,48 @@ use quickcheck::{Arbitrary, Gen};
 
 use crate::base::allocator::Allocator;
 use crate::base::dimension::{Dim, Dynamic};
-use crate::base::Scalar;
 use crate::base::{DefaultAllocator, OMatrix};
 use crate::linalg::givens::GivensRotation;
+use crate::storage::Owned;
 use simba::scalar::ComplexField;
 
 /// A random orthogonal matrix.
-#[derive(Clone, Debug)]
+pub struct RandomOrthogonal<T, D: Dim = Dynamic>
-pub struct RandomOrthogonal<T: Scalar, D: Dim = Dynamic>
 where
     DefaultAllocator: Allocator<T, D, D>,
 {
     m: OMatrix<T, D, D>,
 }
 
+impl<T: Copy, D: Dim> Copy for RandomOrthogonal<T, D>
+where
+    DefaultAllocator: Allocator<T, D, D>,
+    Owned<T, D, D>: Copy,
+{
+}
+
+impl<T: Clone, D: Dim> Clone for RandomOrthogonal<T, D>
+where
+    DefaultAllocator: Allocator<T, D, D>,
+    Owned<T, D, D>: Clone,
+{
+    fn clone(&self) -> Self {
+        Self { m: self.m.clone() }
+    }
+}
+
+impl<T: fmt::Debug, D: Dim> fmt::Debug for RandomOrthogonal<T, D>
+where
+    DefaultAllocator: Allocator<T, D, D>,
+    Owned<T, D, D>: fmt::Debug,
+{
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("RandomOrthogonal")
+            .field("m", &self.m)
+            .finish()
+    }
+}
+
 impl<T: ComplexField, D: Dim> RandomOrthogonal<T, D>
 where
     DefaultAllocator: Allocator<T, D, D>,

src/debug/random_sdp.rs

@@ -1,3 +1,5 @@
+use std::fmt;
+
 #[cfg(feature = "arbitrary")]
 use crate::base::storage::Owned;
 #[cfg(feature = "arbitrary")]
@@ -5,21 +7,47 @@ use quickcheck::{Arbitrary, Gen};
 
 use crate::base::allocator::Allocator;
 use crate::base::dimension::{Dim, Dynamic};
-use crate::base::Scalar;
 use crate::base::{DefaultAllocator, OMatrix};
+use crate::storage::Owned;
 use simba::scalar::ComplexField;
 
 use crate::debug::RandomOrthogonal;
 
 /// A random, well-conditioned, symmetric definite-positive matrix.
-#[derive(Clone, Debug)]
+pub struct RandomSDP<T, D: Dim = Dynamic>
-pub struct RandomSDP<T: Scalar, D: Dim = Dynamic>
 where
     DefaultAllocator: Allocator<T, D, D>,
 {
     m: OMatrix<T, D, D>,
 }
 
+impl<T: Copy, D: Dim> Copy for RandomSDP<T, D>
+where
+    DefaultAllocator: Allocator<T, D, D>,
+    Owned<T, D, D>: Copy,
+{
+}
+
+impl<T: Clone, D: Dim> Clone for RandomSDP<T, D>
+where
+    DefaultAllocator: Allocator<T, D, D>,
+    Owned<T, D, D>: Clone,
+{
+    fn clone(&self) -> Self {
+        Self { m: self.m.clone() }
+    }
+}
+
+impl<T: fmt::Debug, D: Dim> fmt::Debug for RandomSDP<T, D>
+where
+    DefaultAllocator: Allocator<T, D, D>,
+    Owned<T, D, D>: fmt::Debug,
+{
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("RandomSDP").field("m", &self.m).finish()
+    }
+}
+
 impl<T: ComplexField, D: Dim> RandomSDP<T, D>
 where
     DefaultAllocator: Allocator<T, D, D>,

src/geometry/dual_quaternion.rs

@@ -279,8 +279,11 @@ impl<'a, T: Deserialize<'a>> Deserialize<'a> for DualQuaternion<T> {
 
 impl<T> DualQuaternion<T> {
     // TODO: Cloning shouldn't be necessary.
-    fn to_vector(self) -> OVector<T, U8>where T:Clone {
+    fn to_vector(self) -> OVector<T, U8>
-        (*self.as_ref()).into()
+    where
+        T: Clone,
+    {
+        (self.as_ref().clone()).into()
     }
 }
 

src/geometry/point.rs

@@ -5,7 +5,7 @@ use std::fmt;
 use std::hash;
 #[cfg(feature = "abomonation-serialize")]
 use std::io::{Result as IOResult, Write};
-use std::mem::MaybeUninit;
+use std::mem::{ManuallyDrop, MaybeUninit};
 
 #[cfg(feature = "serde-serialize-no-std")]
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
@@ -43,7 +43,6 @@ use crate::Scalar;
 /// may have some other methods, e.g., `isometry.inverse_transform_point(&point)`. See the documentation
 /// of said transformations for details.
 #[repr(C)]
-// TODO: figure out why #[derive(Clone, Debug)] doesn't work!
 pub struct OPoint<T, D: DimName>
 where
     DefaultAllocator: InnerAllocator<T, D>,
@@ -78,6 +77,16 @@ where
     }
 }
 
+impl<T: fmt::Debug, D: DimName> fmt::Debug for OPoint<T, D>
+where
+    DefaultAllocator: Allocator<T, D>,
+    OVector<T, D>: fmt::Debug,
+{
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+     f.debug_struct("OPoint").field("coords",&self.coords).finish()
+ }
+}
+
 #[cfg(feature = "bytemuck")]
 unsafe impl<T, D: DimName> bytemuck::Zeroable for OPoint<T, D>
 where
@@ -185,7 +194,10 @@ where
     /// assert_eq!(p, Point3::new(10.0, 20.0, 30.0));
     /// ```
     #[inline]
-    pub fn apply<F: FnMut(T) -> T>(&mut self, f: F) {
+    pub fn apply<F: FnMut(T) -> T>(&mut self, f: F)
+    where
+        T: Clone,
+    {
         self.coords.apply(f)
     }
 
@@ -224,6 +236,8 @@ where
         unsafe { res.assume_init() }
     }
 
+    /// Converts this point into a vector in homogeneous coordinates, i.e., appends a `1` at the
+    /// end of it. Unlike [`to_homogeneous`], this method does not require `T: Clone`.
     pub fn into_homogeneous(self) -> OVector<T, DimNameSum<D, U1>>
     where
         T: One,
@@ -231,17 +245,15 @@ where
         DefaultAllocator: Allocator<T, DimNameSum<D, U1>>,
     {
         let mut res = OVector::<_, DimNameSum<D, U1>>::new_uninitialized();
+        let mut md = self.manually_drop();
 
-        // TODO: maybe we can move the whole array at once? Or use `into_iter`
-        // to avoid double-dropping.
         for i in 0..D::dim() {
             unsafe {
-                *res.get_unchecked_mut(i) = MaybeUninit::new(*self.coords.get_unchecked(i));
+                *res.get_unchecked_mut(i) =
+                    MaybeUninit::new(ManuallyDrop::take(md.coords.get_unchecked_mut(i)));
             }
         }
 
-        // Fix double drop
-
         unsafe {
             *res.get_unchecked_mut(D::dim()) = MaybeUninit::new(T::one());
             res.assume_init()

src/geometry/point_construction.rs

@@ -1,4 +1,4 @@
-use std::mem::MaybeUninit;
+use std::mem::{ManuallyDrop, MaybeUninit};
 
 #[cfg(feature = "arbitrary")]
 use quickcheck::{Arbitrary, Gen};
@@ -32,6 +32,13 @@ where
         OPoint::from(OVector::new_uninitialized_generic(D::name(), Const::<1>))
     }
 
+    /// Converts `self` into a point whose coordinates must be manually dropped.
+    /// This should be zero-cost.
+    #[inline]
+    pub fn manually_drop(self) -> OPoint<ManuallyDrop<T>, D> {
+        OPoint::from(self.coords.manually_drop())
+    }
+
     /// Creates a new point with all coordinates equal to zero.
     ///
     /// # Example

src/geometry/point_conversion.rs

@@ -91,8 +91,10 @@ impl<T, const D: usize> From<[T; D]> for Point<T, D> {
     }
 }
 
-impl<T, const D: usize> From<Point<T, D>> for [T; D] where
+impl<T, const D: usize> From<Point<T, D>> for [T; D]
-T: Clone,{
+where
+    T: Clone,
+{
     #[inline]
     fn from(p: Point<T, D>) -> Self {
         p.coords.into()

src/geometry/transform_ops.rs

@@ -8,7 +8,8 @@ use simba::scalar::{ClosedAdd, ClosedMul, RealField, SubsetOf};
 
 use crate::base::allocator::Allocator;
 use crate::base::dimension::{DimNameAdd, DimNameSum, U1};
-use crate::base::{Const, DefaultAllocator, OMatrix, SVector, Scalar};use crate::storage::Owned;
+use crate::base::{Const, DefaultAllocator, OMatrix, SVector, Scalar};
+use crate::storage::Owned;
 
 use crate::geometry::{
     Isometry, Point, Rotation, Similarity, SubTCategoryOf, SuperTCategoryOf, TAffine, TCategory,
@@ -344,7 +345,8 @@ md_impl_all!(
     const D;
     for CA, CB;
     where Const<D>: DimNameAdd<U1>, CA: TCategoryMul<CB>, CB: SubTCategoryOf<TProjective>,
-          DefaultAllocator: Allocator<T, DimNameSum<Const<D>, U1>, DimNameSum<Const<D>, U1>>;
+          DefaultAllocator: Allocator<T, DimNameSum<Const<D>, U1>, DimNameSum<Const<D>, U1>>,
+          Transform<T, CB, D>: Clone; // There's probably a better bound here.
     self: Transform<T, CA, D>, rhs: Transform<T, CB, D>, Output = Transform<T, CA::Representative, D>;
     [val val] => #[allow(clippy::suspicious_arithmetic_impl)] { self * rhs.inverse() };
     [ref val] => #[allow(clippy::suspicious_arithmetic_impl)] { self * rhs.inverse() };

src/linalg/permutation_sequence.rs

@@ -99,11 +99,9 @@ where
     /// Creates a new sequence of D identity permutations.
     #[inline]
     pub fn identity_generic(dim: D) -> Self {
-  
         Self {
             len: 0,
             ipiv: OVector::new_uninitialized_generic(dim, Const::<1>),
-            
         }
     }
 

src/proptest/mod.rs

@@ -329,7 +329,7 @@ where
     D: Dim,
     DefaultAllocator: Allocator<ScalarStrategy::Value, D>,
 {
-    matrix_(value_strategy, length.into(), Const::<1>.into())
+    matrix_(value_strategy, length.into(), U1.into())
 }
 
 impl<NParameters, R, C> Default for MatrixParameters<NParameters, R, C>

src/sparse/cs_matrix.rs

@@ -279,7 +279,7 @@ where
         CsMatrix {
             data: CsVecStorage {
                 shape: (nrows, ncols),
-                p: OVector::zeros_generic(ncols, Const::<1>),
+                p: OVector::zeros_generic(ncols, U1),
                 i,
                 vals,
             },
@@ -429,7 +429,7 @@ impl<T: Scalar, R: Dim, C: Dim, S: CsStorage<T, R, C>> CsMatrix<T, R, C, S> {
 
         let nvals = self.len();
         let mut res = CsMatrix::new_uninitialized_generic(ncols, nrows, nvals);
-        let mut workspace = Vector::zeros_generic(nrows, Const::<1>);
+        let mut workspace = Vector::zeros_generic(nrows, U1);
 
         // Compute p.
         for i in 0..nvals {
@@ -473,7 +473,7 @@ where
         // Size = R
         let nrows = self.data.shape().0;
         let mut workspace =
-            unsafe { crate::unimplemented_or_uninitialized_generic!(nrows, Const::<1>) };
+            unsafe { crate::unimplemented_or_uninitialized_generic!(nrows, U1) };
         self.sort_with_workspace(workspace.as_mut_slice());
     }
 

src/sparse/cs_matrix_cholesky.rs

@@ -49,9 +49,9 @@ where
 
         // Workspaces.
         let work_x =
-            unsafe { crate::unimplemented_or_uninitialized_generic!(m.data.shape().0, Const::<1>) };
+            unsafe { crate::unimplemented_or_uninitialized_generic!(m.data.shape().0, U1) };
         let work_c =
-            unsafe { crate::unimplemented_or_uninitialized_generic!(m.data.shape().1, Const::<1>) };
+            unsafe { crate::unimplemented_or_uninitialized_generic!(m.data.shape().1, U1) };
         let mut original_p = m.data.p.as_slice().to_vec();
         original_p.push(m.data.i.len());
 
@@ -295,7 +295,7 @@ where
         let (nrows, ncols) = m.data.shape();
         let mut rows = Vec::with_capacity(m.len());
         let mut cols =
-            unsafe { crate::unimplemented_or_uninitialized_generic!(m.data.shape().0, Const::<1>) };
+            unsafe { crate::unimplemented_or_uninitialized_generic!(m.data.shape().0, U1) };
         let mut marks = Vec::new();
 
         // NOTE: the following will actually compute the non-zero pattern of

src/sparse/cs_matrix_ops.rs

@@ -148,7 +148,7 @@ where
         );
 
         let mut res = CsMatrix::new_uninitialized_generic(nrows1, ncols2, self.len() + rhs.len());
-        let mut workspace = OVector::<T, R1>::zeros_generic(nrows1, Const::<1>);
+        let mut workspace = OVector::<T, R1>::zeros_generic(nrows1, U1);
         let mut nz = 0;
 
         for j in 0..ncols2.value() {
@@ -241,9 +241,9 @@ where
         );
 
         let mut res = CsMatrix::new_uninitialized_generic(nrows1, ncols2, self.len() + rhs.len());
-        let mut timestamps = OVector::zeros_generic(nrows1, Const::<1>);
+        let mut timestamps = OVector::zeros_generic(nrows1, U1);
         let mut workspace =
-            unsafe { crate::unimplemented_or_uninitialized_generic!(nrows1, Const::<1>) };
+            unsafe { crate::unimplemented_or_uninitialized_generic!(nrows1, U1) };
         let mut nz = 0;
 
         for j in 0..ncols2.value() {

src/sparse/cs_matrix_solve.rs

@@ -153,7 +153,7 @@ impl<T: RealField, D: Dim, S: CsStorage<T, D, D>> CsMatrix<T, D, D, S> {
         // We sort the reach so the result matrix has sorted indices.
         reach.sort_unstable();
         let mut workspace =
-            unsafe { crate::unimplemented_or_uninitialized_generic!(b.data.shape().0, Const::<1>) };
+            unsafe { crate::unimplemented_or_uninitialized_generic!(b.data.shape().0, U1) };
 
         for i in reach.iter().cloned() {
             workspace[i] = T::zero();
@@ -191,7 +191,7 @@ impl<T: RealField, D: Dim, S: CsStorage<T, D, D>> CsMatrix<T, D, D, S> {
 
         // Copy the result into a sparse vector.
         let mut result =
-            CsVector::new_uninitialized_generic(b.data.shape().0, Const::<1>, reach.len());
+            CsVector::new_uninitialized_generic(b.data.shape().0, U1, reach.len());
 
         for (i, val) in reach.iter().zip(result.data.vals.iter_mut()) {
             *val = workspace[*i];
@@ -255,7 +255,7 @@ impl<T: RealField, D: Dim, S: CsStorage<T, D, D>> CsMatrix<T, D, D, S> {
         S2: CsStorage<T, D2>,
         DefaultAllocator: Allocator<bool, D>,
     {
-        let mut visited = OVector::repeat_generic(self.data.shape().1, Const::<1>, false);
+        let mut visited = OVector::repeat_generic(self.data.shape().1, U1, false);
         let mut stack = Vec::new();
 
         for irow in b.data.column_row_indices(0) {

tests/proptest/mod.rs

@@ -180,11 +180,11 @@ macro_rules! generate_matrix_sanity_test {
 
 // Test all fixed-size matrices with row/col dimensions up to 3
 generate_matrix_sanity_test!(test_matrix_u0_u0, Const::<0>, Const::<0>);
-generate_matrix_sanity_test!(test_matrix_u1_u0, Const::<1>, Const::<0>);
+generate_matrix_sanity_test!(test_matrix_u1_u0, U1, Const::<0>);
-generate_matrix_sanity_test!(test_matrix_u0_u1, Const::<0>, Const::<1>);
+generate_matrix_sanity_test!(test_matrix_u0_u1, Const::<0>, U1);
-generate_matrix_sanity_test!(test_matrix_u1_u1, Const::<1>, Const::<1>);
+generate_matrix_sanity_test!(test_matrix_u1_u1, U1, U1);
-generate_matrix_sanity_test!(test_matrix_u2_u1, Const::<2>, Const::<1>);
+generate_matrix_sanity_test!(test_matrix_u2_u1, Const::<2>, U1);
-generate_matrix_sanity_test!(test_matrix_u1_u2, Const::<1>, Const::<2>);
+generate_matrix_sanity_test!(test_matrix_u1_u2, U1, Const::<2>);
 generate_matrix_sanity_test!(test_matrix_u2_u2, Const::<2>, Const::<2>);
 generate_matrix_sanity_test!(test_matrix_u3_u2, Const::<3>, Const::<2>);
 generate_matrix_sanity_test!(test_matrix_u2_u3, Const::<2>, Const::<3>);