make fixed-size objects trivially move assignable

diff --git a/Eigen/src/Core/Array.h b/Eigen/src/Core/Array.h
index 2098749..7819305 100644
--- a/Eigen/src/Core/Array.h
+++ b/Eigen/src/Core/Array.h

@@ -123,10 +123,7 @@
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr Array() = default;
 #endif
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr Array(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;
-  }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr Array& operator=(Array&&) = default;
 
   /** \copydoc PlainObjectBase(const Scalar& a0, const Scalar& a1, const Scalar& a2, const Scalar& a3, const
    * ArgTypes&... args)

diff --git a/Eigen/src/Core/ArrayBase.h b/Eigen/src/Core/ArrayBase.h
index 6237df4..de2dafd 100644
--- a/Eigen/src/Core/ArrayBase.h
+++ b/Eigen/src/Core/ArrayBase.h

@@ -147,8 +147,10 @@
   //     inline void evalTo(Dest& dst) const { dst = matrix(); }
 
  protected:
-  EIGEN_DEFAULT_COPY_CONSTRUCTOR(ArrayBase)
-  EIGEN_DEFAULT_EMPTY_CONSTRUCTOR_AND_DESTRUCTOR(ArrayBase)
+  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;
 
  private:
   explicit ArrayBase(Index);

diff --git a/Eigen/src/Core/DenseBase.h b/Eigen/src/Core/DenseBase.h
index e1fbb0b..1a84bd5 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.
@@ -619,8 +619,9 @@
   }
 
  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.

diff --git a/Eigen/src/Core/Matrix.h b/Eigen/src/Core/Matrix.h
index 8b7f70c..522e9c4 100644
--- a/Eigen/src/Core/Matrix.h
+++ b/Eigen/src/Core/Matrix.h

@@ -256,11 +256,7 @@
   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&& other)
-      EIGEN_NOEXCEPT_IF(std::is_nothrow_move_assignable<Scalar>::value) {
-    Base::operator=(std::move(other));
-    return *this;
-  }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr Matrix& operator=(Matrix&&) = default;
 
   /** \copydoc PlainObjectBase(const Scalar&, const Scalar&, const Scalar&,  const Scalar&, const ArgTypes&... args)
    *

diff --git a/Eigen/src/Core/MatrixBase.h b/Eigen/src/Core/MatrixBase.h
index 81d5a97..481b6c1 100644
--- a/Eigen/src/Core/MatrixBase.h
+++ b/Eigen/src/Core/MatrixBase.h

@@ -138,6 +138,8 @@
    */
   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.
 

diff --git a/Eigen/src/Core/PlainObjectBase.h b/Eigen/src/Core/PlainObjectBase.h
index 8720c44..81b9b44 100644
--- a/Eigen/src/Core/PlainObjectBase.h
+++ b/Eigen/src/Core/PlainObjectBase.h

@@ -474,10 +474,7 @@
  protected:
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr PlainObjectBase() = default;
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr PlainObjectBase(PlainObjectBase&&) = default;
-  EIGEN_DEVICE_FUNC constexpr PlainObjectBase& operator=(PlainObjectBase&& other) EIGEN_NOEXCEPT {
-    m_storage = std::move(other.m_storage);
-    return *this;
-  }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr PlainObjectBase& operator=(PlainObjectBase&&) = default;
 
   /** Copy constructor */
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr PlainObjectBase(const PlainObjectBase&) = default;

diff --git a/test/dense_storage.cpp b/test/dense_storage.cpp
index 5d0083f..da30440 100644
--- a/test/dense_storage.cpp
+++ b/test/dense_storage.cpp

@@ -27,7 +27,9 @@
 #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");