Revert "make fixed-size objects trivially move assignable"

Eigen/src/Core/Array.h

diff --git a/Eigen/src/Core/Array.h b/Eigen/src/Core/Array.h
index 7819305..2098749 100644
--- a/Eigen/src/Core/Array.h
+++ b/Eigen/src/Core/Array.h
@@ -123,7 +123,10 @@
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr Array() = default;
 #endif
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr Array(Array&&) = default;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr Array& operator=(Array&&) = default;
+  EIGEN_DEVICE_FUNC Array& operator=(Array&& other) EIGEN_NOEXCEPT_IF(std::is_nothrow_move_assignable<Scalar>::value) {
+    Base::operator=(std::move(other));
+    return *this;
+  }
 
   /** \copydoc PlainObjectBase(const Scalar& a0, const Scalar& a1, const Scalar& a2, const Scalar& a3, const
    * ArgTypes&... args)

Eigen/src/Core/ArrayBase.h

diff --git a/Eigen/src/Core/ArrayBase.h b/Eigen/src/Core/ArrayBase.h
index de2dafd..6237df4 100644
--- a/Eigen/src/Core/ArrayBase.h
+++ b/Eigen/src/Core/ArrayBase.h
@@ -147,10 +147,8 @@
   //     inline void evalTo(Dest& dst) const { dst = matrix(); }
 
  protected:
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr ArrayBase() = default;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr ArrayBase(const ArrayBase&) = default;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr ArrayBase(ArrayBase&&) = default;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr ArrayBase& operator=(ArrayBase&&) = default;
+  EIGEN_DEFAULT_COPY_CONSTRUCTOR(ArrayBase)
+  EIGEN_DEFAULT_EMPTY_CONSTRUCTOR_AND_DESTRUCTOR(ArrayBase)
 
  private:
   explicit ArrayBase(Index);

Eigen/src/Core/DenseBase.h

diff --git a/Eigen/src/Core/DenseBase.h b/Eigen/src/Core/DenseBase.h
index 1a84bd5..e1fbb0b 100644
--- a/Eigen/src/Core/DenseBase.h
+++ b/Eigen/src/Core/DenseBase.h
@@ -573,12 +573,12 @@
 #else
   typedef std::conditional_t<(Flags & DirectAccessBit) == DirectAccessBit,
                              internal::pointer_based_stl_iterator<Derived>,
-                             internal::generic_randaccess_stl_iterator<Derived>>
+                             internal::generic_randaccess_stl_iterator<Derived> >
       iterator_type;
 
   typedef std::conditional_t<(Flags & DirectAccessBit) == DirectAccessBit,
                              internal::pointer_based_stl_iterator<const Derived>,
-                             internal::generic_randaccess_stl_iterator<const Derived>>
+                             internal::generic_randaccess_stl_iterator<const Derived> >
       const_iterator_type;
 
   // Stl-style iterators are supported only for vectors.
@@ -619,9 +619,8 @@
   }
 
  protected:
+  EIGEN_DEFAULT_COPY_CONSTRUCTOR(DenseBase)
   /** Default constructor. Do nothing. */
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr DenseBase(const DenseBase&) = default;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr DenseBase& operator=(DenseBase&&) = default;
 #ifdef EIGEN_INTERNAL_DEBUGGING
   EIGEN_DEVICE_FUNC constexpr DenseBase() {
     /* Just checks for self-consistency of the flags.

Eigen/src/Core/Matrix.h

diff --git a/Eigen/src/Core/Matrix.h b/Eigen/src/Core/Matrix.h
index 522e9c4..8b7f70c 100644
--- a/Eigen/src/Core/Matrix.h
+++ b/Eigen/src/Core/Matrix.h
@@ -256,7 +256,11 @@
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr Matrix() = default;
 #endif
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr Matrix(Matrix&&) = default;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr Matrix& operator=(Matrix&&) = default;
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr Matrix& operator=(Matrix&& other)
+      EIGEN_NOEXCEPT_IF(std::is_nothrow_move_assignable<Scalar>::value) {
+    Base::operator=(std::move(other));
+    return *this;
+  }
 
   /** \copydoc PlainObjectBase(const Scalar&, const Scalar&, const Scalar&,  const Scalar&, const ArgTypes&... args)
    *

Eigen/src/Core/MatrixBase.h

diff --git a/Eigen/src/Core/MatrixBase.h b/Eigen/src/Core/MatrixBase.h
index 481b6c1..81d5a97 100644
--- a/Eigen/src/Core/MatrixBase.h
+++ b/Eigen/src/Core/MatrixBase.h
@@ -138,8 +138,6 @@
    */
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Derived& operator=(const MatrixBase& other);
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr MatrixBase& operator=(MatrixBase&&) = default;
-
   // We cannot inherit here via Base::operator= since it is causing
   // trouble with MSVC.
 

Eigen/src/Core/PlainObjectBase.h

diff --git a/Eigen/src/Core/PlainObjectBase.h b/Eigen/src/Core/PlainObjectBase.h
index 81b9b44..8720c44 100644
--- a/Eigen/src/Core/PlainObjectBase.h
+++ b/Eigen/src/Core/PlainObjectBase.h
@@ -474,7 +474,10 @@
  protected:
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr PlainObjectBase() = default;
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr PlainObjectBase(PlainObjectBase&&) = default;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr PlainObjectBase& operator=(PlainObjectBase&&) = default;
+  EIGEN_DEVICE_FUNC constexpr PlainObjectBase& operator=(PlainObjectBase&& other) EIGEN_NOEXCEPT {
+    m_storage = std::move(other.m_storage);
+    return *this;
+  }
 
   /** Copy constructor */
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr PlainObjectBase(const PlainObjectBase&) = default;

test/dense_storage.cpp

diff --git a/test/dense_storage.cpp b/test/dense_storage.cpp
index da30440..5d0083f 100644
--- a/test/dense_storage.cpp
+++ b/test/dense_storage.cpp
@@ -27,9 +27,7 @@
 #endif
 
 static_assert(std::is_trivially_move_constructible<Matrix4f>::value, "Matrix4f not trivially_move_constructible");
-static_assert(std::is_trivially_move_assignable<Matrix4f>::value, "Matrix4f not trivially_move_assignable");
 static_assert(std::is_trivially_move_constructible<Array4f>::value, "Array4f not trivially_move_constructible");
-static_assert(std::is_trivially_move_assignable<Array4f>::value, "Array4f not trivially_move_assignable");
 #if !defined(EIGEN_DENSE_STORAGE_CTOR_PLUGIN)
 static_assert(std::is_trivially_copy_constructible<Matrix4f>::value, "Matrix4f not trivially_copy_constructible");
 static_assert(std::is_trivially_copy_constructible<Array4f>::value, "Array4f not trivially_copy_constructible");