Remove backfills of some type traits that are now fully supported

PiperOrigin-RevId: 512622121
Change-Id: If90aaf7939062bd475253c372d9d7950c98c7150

2 files changed, 21 insertions, 1020 deletions

diff --git a/absl/meta/type_traits.h b/absl/meta/type_traits.h
index b1656c39..fb12ba4a 100644
--- a/absl/meta/type_traits.h
+++ b/absl/meta/type_traits.h
@@ -41,12 +41,6 @@
 
 #include "absl/base/config.h"
 
-// MSVC constructibility traits do not detect destructor properties and so our
-// implementations should not use them as a source-of-truth.
-#if defined(_MSC_VER) && !defined(__clang__) && !defined(__GNUC__)
-#define ABSL_META_INTERNAL_STD_CONSTRUCTION_TRAITS_DONT_CHECK_DESTRUCTION 1
-#endif
-
 // Defines the default alignment. `__STDCPP_DEFAULT_NEW_ALIGNMENT__` is a C++17
 // feature.
 #if defined(__STDCPP_DEFAULT_NEW_ALIGNMENT__)
@@ -58,57 +52,8 @@
 namespace absl {
 ABSL_NAMESPACE_BEGIN
 
-// Defined and documented later on in this file.
-template <typename T>
-struct is_trivially_destructible;
-
-// Defined and documented later on in this file.
-template <typename T>
-struct is_trivially_move_assignable;
-
 namespace type_traits_internal {
 
-// Silence MSVC warnings about the destructor being defined as deleted.
-#if defined(_MSC_VER) && !defined(__GNUC__)
-#pragma warning(push)
-#pragma warning(disable : 4624)
-#endif  // defined(_MSC_VER) && !defined(__GNUC__)
-
-template <class T>
-union SingleMemberUnion {
-  T t;
-};
-
-// Restore the state of the destructor warning that was silenced above.
-#if defined(_MSC_VER) && !defined(__GNUC__)
-#pragma warning(pop)
-#endif  // defined(_MSC_VER) && !defined(__GNUC__)
-
-template <class T>
-struct IsTriviallyMoveConstructibleObject
-    : std::integral_constant<
-          bool, std::is_move_constructible<
-                    type_traits_internal::SingleMemberUnion<T>>::value &&
-                    absl::is_trivially_destructible<T>::value> {};
-
-template <class T>
-struct IsTriviallyCopyConstructibleObject
-    : std::integral_constant<
-          bool, std::is_copy_constructible<
-                    type_traits_internal::SingleMemberUnion<T>>::value &&
-                    absl::is_trivially_destructible<T>::value> {};
-
-template <class T>
-struct IsTriviallyMoveAssignableReference : std::false_type {};
-
-template <class T>
-struct IsTriviallyMoveAssignableReference<T&>
-    : absl::is_trivially_move_assignable<T>::type {};
-
-template <class T>
-struct IsTriviallyMoveAssignableReference<T&&>
-    : absl::is_trivially_move_assignable<T>::type {};
-
 template <typename... Ts>
 struct VoidTImpl {
   using type = void;
@@ -157,39 +102,8 @@ template <class To, template <class...> class Op, class... Args>
 struct is_detected_convertible
     : is_detected_convertible_impl<void, To, Op, Args...>::type {};
 
-template <typename T>
-using IsCopyAssignableImpl =
-    decltype(std::declval<T&>() = std::declval<const T&>());
-
-template <typename T>
-using IsMoveAssignableImpl = decltype(std::declval<T&>() = std::declval<T&&>());
-
 }  // namespace type_traits_internal
 
-// MSVC 19.20 has a regression that causes our workarounds to fail, but their
-// std forms now appear to be compliant.
-#if defined(_MSC_VER) && !defined(__clang__) && (_MSC_VER >= 1920)
-
-template <typename T>
-using is_copy_assignable = std::is_copy_assignable<T>;
-
-template <typename T>
-using is_move_assignable = std::is_move_assignable<T>;
-
-#else
-
-template <typename T>
-struct is_copy_assignable : type_traits_internal::is_detected<
-                                type_traits_internal::IsCopyAssignableImpl, T> {
-};
-
-template <typename T>
-struct is_move_assignable : type_traits_internal::is_detected<
-                                type_traits_internal::IsMoveAssignableImpl, T> {
-};
-
-#endif
-
 // void_t()
 //
 // Ignores the type of any its arguments and returns `void`. In general, this
@@ -270,246 +184,29 @@ struct is_function
           bool, !(std::is_reference<T>::value ||
                   std::is_const<typename std::add_const<T>::type>::value)> {};
 
+// is_copy_assignable()
+// is_move_assignable()
 // is_trivially_destructible()
-//
-// Determines whether the passed type `T` is trivially destructible.
-//
-// This metafunction is designed to be a drop-in replacement for the C++11
-// `std::is_trivially_destructible()` metafunction for platforms that have
-// incomplete C++11 support (such as libstdc++ 4.x). On any platforms that do
-// fully support C++11, we check whether this yields the same result as the std
-// implementation.
-//
-// NOTE: the extensions (__has_trivial_xxx) are implemented in gcc (version >=
-// 4.3) and clang. Since we are supporting libstdc++ > 4.7, they should always
-// be present. These  extensions are documented at
-// https://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html#Type-Traits.
-template <typename T>
-struct is_trivially_destructible
-#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE
-    : std::is_trivially_destructible<T> {
-#else
-    : std::integral_constant<bool, __has_trivial_destructor(T) &&
-                                   std::is_destructible<T>::value> {
-#endif
-#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE
- private:
-  static constexpr bool compliant = std::is_trivially_destructible<T>::value ==
-                                    is_trivially_destructible::value;
-  static_assert(compliant || std::is_trivially_destructible<T>::value,
-                "Not compliant with std::is_trivially_destructible; "
-                "Standard: false, Implementation: true");
-  static_assert(compliant || !std::is_trivially_destructible<T>::value,
-                "Not compliant with std::is_trivially_destructible; "
-                "Standard: true, Implementation: false");
-#endif  // ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE
-};
-
 // is_trivially_default_constructible()
-//
-// Determines whether the passed type `T` is trivially default constructible.
-//
-// This metafunction is designed to be a drop-in replacement for the C++11
-// `std::is_trivially_default_constructible()` metafunction for platforms that
-// have incomplete C++11 support (such as libstdc++ 4.x). On any platforms that
-// do fully support C++11, we check whether this yields the same result as the
-// std implementation.
-//
-// NOTE: according to the C++ standard, Section: 20.15.4.3 [meta.unary.prop]
-// "The predicate condition for a template specialization is_constructible<T,
-// Args...> shall be satisfied if and only if the following variable
-// definition would be well-formed for some invented variable t:
-//
-// T t(declval<Args>()...);
-//
-// is_trivially_constructible<T, Args...> additionally requires that the
-// variable definition does not call any operation that is not trivial.
-// For the purposes of this check, the call to std::declval is considered
-// trivial."
-//
-// Notes from https://en.cppreference.com/w/cpp/types/is_constructible:
-// In many implementations, is_nothrow_constructible also checks if the
-// destructor throws because it is effectively noexcept(T(arg)). Same
-// applies to is_trivially_constructible, which, in these implementations, also
-// requires that the destructor is trivial.
-// GCC bug 51452: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51452
-// LWG issue 2116: http://cplusplus.github.io/LWG/lwg-active.html#2116.
-//
-// "T obj();" need to be well-formed and not call any nontrivial operation.
-// Nontrivially destructible types will cause the expression to be nontrivial.
-template <typename T>
-struct is_trivially_default_constructible
-#if defined(ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE)
-    : std::is_trivially_default_constructible<T> {
-#else
-    : std::integral_constant<bool, __has_trivial_constructor(T) &&
-                                   std::is_default_constructible<T>::value &&
-                                   is_trivially_destructible<T>::value> {
-#endif
-#if defined(ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE) && \
-    !defined(                                            \
-        ABSL_META_INTERNAL_STD_CONSTRUCTION_TRAITS_DONT_CHECK_DESTRUCTION)
- private:
-  static constexpr bool compliant =
-      std::is_trivially_default_constructible<T>::value ==
-      is_trivially_default_constructible::value;
-  static_assert(compliant || std::is_trivially_default_constructible<T>::value,
-                "Not compliant with std::is_trivially_default_constructible; "
-                "Standard: false, Implementation: true");
-  static_assert(compliant || !std::is_trivially_default_constructible<T>::value,
-                "Not compliant with std::is_trivially_default_constructible; "
-                "Standard: true, Implementation: false");
-#endif  // ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE
-};
-
 // is_trivially_move_constructible()
-//
-// Determines whether the passed type `T` is trivially move constructible.
-//
-// This metafunction is designed to be a drop-in replacement for the C++11
-// `std::is_trivially_move_constructible()` metafunction for platforms that have
-// incomplete C++11 support (such as libstdc++ 4.x). On any platforms that do
-// fully support C++11, we check whether this yields the same result as the std
-// implementation.
-//
-// NOTE: `T obj(declval<T>());` needs to be well-formed and not call any
-// nontrivial operation.  Nontrivially destructible types will cause the
-// expression to be nontrivial.
-template <typename T>
-struct is_trivially_move_constructible
-#if defined(ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE)
-    : std::is_trivially_move_constructible<T> {
-#else
-    : std::conditional<
-          std::is_object<T>::value && !std::is_array<T>::value,
-          type_traits_internal::IsTriviallyMoveConstructibleObject<T>,
-          std::is_reference<T>>::type::type {
-#endif
-#if defined(ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE) && \
-    !defined(                                            \
-        ABSL_META_INTERNAL_STD_CONSTRUCTION_TRAITS_DONT_CHECK_DESTRUCTION)
- private:
-  static constexpr bool compliant =
-      std::is_trivially_move_constructible<T>::value ==
-      is_trivially_move_constructible::value;
-  static_assert(compliant || std::is_trivially_move_constructible<T>::value,
-                "Not compliant with std::is_trivially_move_constructible; "
-                "Standard: false, Implementation: true");
-  static_assert(compliant || !std::is_trivially_move_constructible<T>::value,
-                "Not compliant with std::is_trivially_move_constructible; "
-                "Standard: true, Implementation: false");
-#endif  // ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE
-};
-
 // is_trivially_copy_constructible()
-//
-// Determines whether the passed type `T` is trivially copy constructible.
-//
-// This metafunction is designed to be a drop-in replacement for the C++11
-// `std::is_trivially_copy_constructible()` metafunction for platforms that have
-// incomplete C++11 support (such as libstdc++ 4.x). On any platforms that do
-// fully support C++11, we check whether this yields the same result as the std
-// implementation.
-//
-// NOTE: `T obj(declval<const T&>());` needs to be well-formed and not call any
-// nontrivial operation.  Nontrivially destructible types will cause the
-// expression to be nontrivial.
-template <typename T>
-struct is_trivially_copy_constructible
-    : std::conditional<
-          std::is_object<T>::value && !std::is_array<T>::value,
-          type_traits_internal::IsTriviallyCopyConstructibleObject<T>,
-          std::is_lvalue_reference<T>>::type::type {
-#if defined(ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE) && \
-    !defined(                                            \
-        ABSL_META_INTERNAL_STD_CONSTRUCTION_TRAITS_DONT_CHECK_DESTRUCTION)
- private:
-  static constexpr bool compliant =
-      std::is_trivially_copy_constructible<T>::value ==
-      is_trivially_copy_constructible::value;
-  static_assert(compliant || std::is_trivially_copy_constructible<T>::value,
-                "Not compliant with std::is_trivially_copy_constructible; "
-                "Standard: false, Implementation: true");
-  static_assert(compliant || !std::is_trivially_copy_constructible<T>::value,
-                "Not compliant with std::is_trivially_copy_constructible; "
-                "Standard: true, Implementation: false");
-#endif  // ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE
-};
-
 // is_trivially_move_assignable()
-//
-// Determines whether the passed type `T` is trivially move assignable.
-//
-// This metafunction is designed to be a drop-in replacement for the C++11
-// `std::is_trivially_move_assignable()` metafunction for platforms that have
-// incomplete C++11 support (such as libstdc++ 4.x). On any platforms that do
-// fully support C++11, we check whether this yields the same result as the std
-// implementation.
-//
-// NOTE: `is_assignable<T, U>::value` is `true` if the expression
-// `declval<T>() = declval<U>()` is well-formed when treated as an unevaluated
-// operand. `is_trivially_assignable<T, U>` requires the assignment to call no
-// operation that is not trivial. `is_trivially_copy_assignable<T>` is simply
-// `is_trivially_assignable<T&, T>`.
-template <typename T>
-struct is_trivially_move_assignable
-    : std::conditional<
-          std::is_object<T>::value && !std::is_array<T>::value &&
-              std::is_move_assignable<T>::value,
-          std::is_move_assignable<type_traits_internal::SingleMemberUnion<T>>,
-          type_traits_internal::IsTriviallyMoveAssignableReference<T>>::type::
-          type {
-#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE
- private:
-  static constexpr bool compliant =
-      std::is_trivially_move_assignable<T>::value ==
-      is_trivially_move_assignable::value;
-  static_assert(compliant || std::is_trivially_move_assignable<T>::value,
-                "Not compliant with std::is_trivially_move_assignable; "
-                "Standard: false, Implementation: true");
-  static_assert(compliant || !std::is_trivially_move_assignable<T>::value,
-                "Not compliant with std::is_trivially_move_assignable; "
-                "Standard: true, Implementation: false");
-#endif  // ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE
-};
-
 // is_trivially_copy_assignable()
 //
-// Determines whether the passed type `T` is trivially copy assignable.
-//
-// This metafunction is designed to be a drop-in replacement for the C++11
-// `std::is_trivially_copy_assignable()` metafunction for platforms that have
-// incomplete C++11 support (such as libstdc++ 4.x). On any platforms that do
-// fully support C++11, we check whether this yields the same result as the std
-// implementation.
-//
-// NOTE: `is_assignable<T, U>::value` is `true` if the expression
-// `declval<T>() = declval<U>()` is well-formed when treated as an unevaluated
-// operand. `is_trivially_assignable<T, U>` requires the assignment to call no
-// operation that is not trivial. `is_trivially_copy_assignable<T>` is simply
-// `is_trivially_assignable<T&, const T&>`.
-template <typename T>
-struct is_trivially_copy_assignable
-#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE
-    : std::is_trivially_copy_assignable<T> {
-#else
-    : std::integral_constant<
-          bool, __has_trivial_assign(typename std::remove_reference<T>::type) &&
-                    absl::is_copy_assignable<T>::value> {
-#endif
-#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE
- private:
-  static constexpr bool compliant =
-      std::is_trivially_copy_assignable<T>::value ==
-      is_trivially_copy_assignable::value;
-  static_assert(compliant || std::is_trivially_copy_assignable<T>::value,
-                "Not compliant with std::is_trivially_copy_assignable; "
-                "Standard: false, Implementation: true");
-  static_assert(compliant || !std::is_trivially_copy_assignable<T>::value,
-                "Not compliant with std::is_trivially_copy_assignable; "
-                "Standard: true, Implementation: false");
-#endif  // ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE
-};
+// Historical note: Abseil once provided implementations of these type traits
+// for platforms that lacked full support. New code should prefer to use the
+// std variants.
+//
+// See the documentation for the STL <type_traits> header for more information:
+// https://en.cppreference.com/w/cpp/header/type_traits
+using std::is_copy_assignable;
+using std::is_move_assignable;
+using std::is_trivially_copy_assignable;
+using std::is_trivially_copy_constructible;
+using std::is_trivially_default_constructible;
+using std::is_trivially_destructible;
+using std::is_trivially_move_assignable;
+using std::is_trivially_move_constructible;
 
 #if defined(__cpp_lib_remove_cvref) && __cpp_lib_remove_cvref >= 201711L
 template <typename T>
@@ -533,52 +230,11 @@ using remove_cvref_t = typename remove_cvref<T>::type;
 #endif
 
 namespace type_traits_internal {
-// is_trivially_copyable()
-//
-// Determines whether the passed type `T` is trivially copyable.
-//
-// This metafunction is designed to be a drop-in replacement for the C++11
-// `std::is_trivially_copyable()` metafunction for platforms that have
-// incomplete C++11 support (such as libstdc++ 4.x). We use the C++17 definition
-// of TriviallyCopyable.
-//
-// NOTE: `is_trivially_copyable<T>::value` is `true` if all of T's copy/move
-// constructors/assignment operators are trivial or deleted, T has at least
-// one non-deleted copy/move constructor/assignment operator, and T is trivially
-// destructible. Arrays of trivially copyable types are trivially copyable.
-//
-// We expose this metafunction only for internal use within absl.
-
-#if defined(ABSL_HAVE_STD_IS_TRIVIALLY_COPYABLE)
-template <typename T>
-struct is_trivially_copyable : std::is_trivially_copyable<T> {};
-#else
-template <typename T>
-class is_trivially_copyable_impl {
-  using ExtentsRemoved = typename std::remove_all_extents<T>::type;
-  static constexpr bool kIsCopyOrMoveConstructible =
-      std::is_copy_constructible<ExtentsRemoved>::value ||
-      std::is_move_constructible<ExtentsRemoved>::value;
-  static constexpr bool kIsCopyOrMoveAssignable =
-      absl::is_copy_assignable<ExtentsRemoved>::value ||
-      absl::is_move_assignable<ExtentsRemoved>::value;
-
- public:
-  static constexpr bool kValue =
-      (__has_trivial_copy(ExtentsRemoved) || !kIsCopyOrMoveConstructible) &&
-      (__has_trivial_assign(ExtentsRemoved) || !kIsCopyOrMoveAssignable) &&
-      (kIsCopyOrMoveConstructible || kIsCopyOrMoveAssignable) &&
-      is_trivially_destructible<ExtentsRemoved>::value &&
-      // We need to check for this explicitly because otherwise we'll say
-      // references are trivial copyable when compiled by MSVC.
-      !std::is_reference<ExtentsRemoved>::value;
-};
-
-template <typename T>
-struct is_trivially_copyable
-    : std::integral_constant<
-          bool, type_traits_internal::is_trivially_copyable_impl<T>::kValue> {};
-#endif
+// An implementation of std::is_trivially_copyable was once provided for
+// internal use within absl.
+// TODO(absl-team): Replace absl::type_traits_internal::is_trivially_copyable
+// with std::is_trivially_copyable and delete this using declaration.
+using std::is_trivially_copyable;
 }  // namespace type_traits_internal
 
 // -----------------------------------------------------------------------------
diff --git a/absl/meta/type_traits_test.cc b/absl/meta/type_traits_test.cc
index b2a7a67b..4165fef5 100644
--- a/absl/meta/type_traits_test.cc
+++ b/absl/meta/type_traits_test.cc
@@ -352,29 +352,6 @@ class Base {
   virtual ~Base() {}
 };
 
-// Old versions of libc++, around Clang 3.5 to 3.6, consider deleted destructors
-// as also being trivial. With the resolution of CWG 1928 and CWG 1734, this
-// is no longer considered true and has thus been amended.
-// Compiler Explorer: https://godbolt.org/g/zT59ZL
-// CWG issue 1734: http://open-std.org/JTC1/SC22/WG21/docs/cwg_defects.html#1734
-// CWG issue 1928: http://open-std.org/JTC1/SC22/WG21/docs/cwg_closed.html#1928
-#if !defined(_LIBCPP_VERSION) || _LIBCPP_VERSION >= 3700
-#define ABSL_TRIVIALLY_DESTRUCTIBLE_CONSIDER_DELETED_DESTRUCTOR_NOT_TRIVIAL 1
-#endif
-
-// As of the moment, GCC versions >5.1 have a problem compiling for
-// std::is_trivially_default_constructible<NontrivialDestructor[10]>, where
-// NontrivialDestructor is a struct with a custom nontrivial destructor. Note
-// that this problem only occurs for arrays of a known size, so something like
-// std::is_trivially_default_constructible<NontrivialDestructor[]> does not
-// have any problems.
-// Compiler Explorer: https://godbolt.org/g/dXRbdK
-// GCC bug 83689: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83689
-#if defined(__clang__) || defined(_MSC_VER) || \
-    (defined(__GNUC__) && __GNUC__ < 5)
-#define ABSL_GCC_BUG_TRIVIALLY_CONSTRUCTIBLE_ON_ARRAY_OF_NONTRIVIAL 1
-#endif
-
 TEST(TypeTraitsTest, TestIsFunction) {
   struct Callable {
     void operator()() {}
@@ -391,562 +368,6 @@ TEST(TypeTraitsTest, TestIsFunction) {
   EXPECT_FALSE(absl::is_function<Callable>::value);
 }
 
-TEST(TypeTraitsTest, TestTrivialDestructor) {
-  // Verify that arithmetic types and pointers have trivial destructors.
-  EXPECT_TRUE(absl::is_trivially_destructible<bool>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<char>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<unsigned char>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<signed char>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<wchar_t>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<int>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<unsigned int>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<int16_t>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<uint16_t>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<int64_t>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<uint64_t>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<float>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<double>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<long double>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<std::string*>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<Trivial*>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<const std::string*>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<const Trivial*>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<std::string**>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<Trivial**>::value);
-
-  // classes with destructors
-  EXPECT_TRUE(absl::is_trivially_destructible<Trivial>::value);
-  EXPECT_TRUE(absl::is_trivially_destructible<TrivialDestructor>::value);
-
-  // Verify that types with a nontrivial or deleted destructor
-  // are marked as such.
-  EXPECT_FALSE(absl::is_trivially_destructible<NontrivialDestructor>::value);
-#ifdef ABSL_TRIVIALLY_DESTRUCTIBLE_CONSIDER_DELETED_DESTRUCTOR_NOT_TRIVIAL
-  EXPECT_FALSE(absl::is_trivially_destructible<DeletedDestructor>::value);
-#endif
-
-  // simple_pair of such types is trivial
-  EXPECT_TRUE((absl::is_trivially_destructible<simple_pair<int, int>>::value));
-  EXPECT_TRUE((absl::is_trivially_destructible<
-               simple_pair<Trivial, TrivialDestructor>>::value));
-
-  // Verify that types without trivial destructors are correctly marked as such.
-  EXPECT_FALSE(absl::is_trivially_destructible<std::string>::value);
-  EXPECT_FALSE(absl::is_trivially_destructible<std::vector<int>>::value);
-
-  // Verify that simple_pairs of types without trivial destructors
-  // are not marked as trivial.
-  EXPECT_FALSE((absl::is_trivially_destructible<
-                simple_pair<int, std::string>>::value));
-  EXPECT_FALSE((absl::is_trivially_destructible<
-                simple_pair<std::string, int>>::value));
-
-  // array of such types is trivial
-  using int10 = int[10];
-  EXPECT_TRUE(absl::is_trivially_destructible<int10>::value);
-  using Trivial10 = Trivial[10];
-  EXPECT_TRUE(absl::is_trivially_destructible<Trivial10>::value);
-  using TrivialDestructor10 = TrivialDestructor[10];
-  EXPECT_TRUE(absl::is_trivially_destructible<TrivialDestructor10>::value);
-
-  // Conversely, the opposite also holds.
-  using NontrivialDestructor10 = NontrivialDestructor[10];
-  EXPECT_FALSE(absl::is_trivially_destructible<NontrivialDestructor10>::value);
-}
-
-TEST(TypeTraitsTest, TestTrivialDefaultCtor) {
-  // arithmetic types and pointers have trivial default constructors.
-  EXPECT_TRUE(absl::is_trivially_default_constructible<bool>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<char>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<unsigned char>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<signed char>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<wchar_t>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<int>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<unsigned int>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<int16_t>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<uint16_t>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<int64_t>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<uint64_t>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<float>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<double>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<long double>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<std::string*>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<Trivial*>::value);
-  EXPECT_TRUE(
-      absl::is_trivially_default_constructible<const std::string*>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<const Trivial*>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<std::string**>::value);
-  EXPECT_TRUE(absl::is_trivially_default_constructible<Trivial**>::value);
-
-  // types with compiler generated default ctors
-  EXPECT_TRUE(absl::is_trivially_default_constructible<Trivial>::value);
-  EXPECT_TRUE(
-      absl::is_trivially_default_constructible<TrivialDefaultCtor>::value);
-
-  // Verify that types without them are not.
-  EXPECT_FALSE(
-      absl::is_trivially_default_constructible<NontrivialDefaultCtor>::value);
-  EXPECT_FALSE(
-      absl::is_trivially_default_constructible<DeletedDefaultCtor>::value);
-
-  // types with nontrivial destructor are nontrivial
-  EXPECT_FALSE(
-      absl::is_trivially_default_constructible<NontrivialDestructor>::value);
-
-  // types with vtables
-  EXPECT_FALSE(absl::is_trivially_default_constructible<Base>::value);
-
-  // Verify that simple_pair has trivial constructors where applicable.
-  EXPECT_TRUE((absl::is_trivially_default_constructible<
-               simple_pair<int, char*>>::value));
-  EXPECT_TRUE((absl::is_trivially_default_constructible<
-               simple_pair<int, Trivial>>::value));
-  EXPECT_TRUE((absl::is_trivially_default_constructible<
-               simple_pair<int, TrivialDefaultCtor>>::value));
-
-  // Verify that types without trivial constructors are
-  // correctly marked as such.
-  EXPECT_FALSE(absl::is_trivially_default_constructible<std::string>::value);
-  EXPECT_FALSE(
-      absl::is_trivially_default_constructible<std::vector<int>>::value);
-
-  // Verify that simple_pairs of types without trivial constructors
-  // are not marked as trivial.
-  EXPECT_FALSE((absl::is_trivially_default_constructible<
-                simple_pair<int, std::string>>::value));
-  EXPECT_FALSE((absl::is_trivially_default_constructible<
-                simple_pair<std::string, int>>::value));
-
-  // Verify that arrays of such types are trivially default constructible
-  using int10 = int[10];
-  EXPECT_TRUE(absl::is_trivially_default_constructible<int10>::value);
-  using Trivial10 = Trivial[10];
-  EXPECT_TRUE(absl::is_trivially_default_constructible<Trivial10>::value);
-  using TrivialDefaultCtor10 = TrivialDefaultCtor[10];
-  EXPECT_TRUE(
-      absl::is_trivially_default_constructible<TrivialDefaultCtor10>::value);
-
-  // Conversely, the opposite also holds.
-#ifdef ABSL_GCC_BUG_TRIVIALLY_CONSTRUCTIBLE_ON_ARRAY_OF_NONTRIVIAL
-  using NontrivialDefaultCtor10 = NontrivialDefaultCtor[10];
-  EXPECT_FALSE(
-      absl::is_trivially_default_constructible<NontrivialDefaultCtor10>::value);
-#endif
-}
-
-// GCC prior to 7.4 had a bug in its trivially-constructible traits
-// (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80654).
-// This test makes sure that we do not depend on the trait in these cases when
-// implementing absl triviality traits.
-
-template <class T>
-struct BadConstructors {
-  BadConstructors() { static_assert(T::value, ""); }
-
-  BadConstructors(BadConstructors&&) { static_assert(T::value, ""); }
-
-  BadConstructors(const BadConstructors&) { static_assert(T::value, ""); }
-};
-
-TEST(TypeTraitsTest, TestTrivialityBadConstructors) {
-  using BadType = BadConstructors<int>;
-
-  EXPECT_FALSE(absl::is_trivially_default_constructible<BadType>::value);
-  EXPECT_FALSE(absl::is_trivially_move_constructible<BadType>::value);
-  EXPECT_FALSE(absl::is_trivially_copy_constructible<BadType>::value);
-}
-
-TEST(TypeTraitsTest, TestTrivialMoveCtor) {
-  // Verify that arithmetic types and pointers have trivial move
-  // constructors.
-  EXPECT_TRUE(absl::is_trivially_move_constructible<bool>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<char>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<unsigned char>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<signed char>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<wchar_t>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<int>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<unsigned int>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<int16_t>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<uint16_t>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<int64_t>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<uint64_t>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<float>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<double>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<long double>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<std::string*>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<Trivial*>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<const std::string*>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<const Trivial*>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<std::string**>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<Trivial**>::value);
-
-  // Reference types
-  EXPECT_TRUE(absl::is_trivially_move_constructible<int&>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<int&&>::value);
-
-  // types with compiler generated move ctors
-  EXPECT_TRUE(absl::is_trivially_move_constructible<Trivial>::value);
-  EXPECT_TRUE(absl::is_trivially_move_constructible<TrivialMoveCtor>::value);
-
-  // Verify that types without them (i.e. nontrivial or deleted) are not.
-  EXPECT_FALSE(
-      absl::is_trivially_move_constructible<NontrivialCopyCtor>::value);
-  EXPECT_FALSE(absl::is_trivially_move_constructible<DeletedCopyCtor>::value);
-  EXPECT_FALSE(
-      absl::is_trivially_move_constructible<NonCopyableOrMovable>::value);
-
-  // type with nontrivial destructor are nontrivial move construbtible
-  EXPECT_FALSE(
-      absl::is_trivially_move_constructible<NontrivialDestructor>::value);
-
-  // types with vtables
-  EXPECT_FALSE(absl::is_trivially_move_constructible<Base>::value);
-
-  // Verify that simple_pair of such types is trivially move constructible
-  EXPECT_TRUE(
-      (absl::is_trivially_move_constructible<simple_pair<int, char*>>::value));
-  EXPECT_TRUE((
-      absl::is_trivially_move_constructible<simple_pair<int, Trivial>>::value));
-  EXPECT_TRUE((absl::is_trivially_move_constructible<
-               simple_pair<int, TrivialMoveCtor>>::value));
-
-  // Verify that types without trivial move constructors are
-  // correctly marked as such.
-  EXPECT_FALSE(absl::is_trivially_move_constructible<std::string>::value);
-  EXPECT_FALSE(absl::is_trivially_move_constructible<std::vector<int>>::value);
-
-  // Verify that simple_pairs of types without trivial move constructors
-  // are not marked as trivial.
-  EXPECT_FALSE((absl::is_trivially_move_constructible<
-                simple_pair<int, std::string>>::value));
-  EXPECT_FALSE((absl::is_trivially_move_constructible<
-                simple_pair<std::string, int>>::value));
-
-  // Verify that arrays are not
-  using int10 = int[10];
-  EXPECT_FALSE(absl::is_trivially_move_constructible<int10>::value);
-}
-
-TEST(TypeTraitsTest, TestTrivialCopyCtor) {
-  // Verify that arithmetic types and pointers have trivial copy
-  // constructors.
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<bool>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<char>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<unsigned char>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<signed char>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<wchar_t>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<int>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<unsigned int>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<int16_t>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<uint16_t>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<int64_t>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<uint64_t>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<float>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<double>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<long double>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<std::string*>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<Trivial*>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<const std::string*>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<const Trivial*>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<std::string**>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<Trivial**>::value);
-
-  // Reference types
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<int&>::value);
-  EXPECT_FALSE(absl::is_trivially_copy_constructible<int&&>::value);
-
-  // types with compiler generated copy ctors
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<Trivial>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_constructible<TrivialCopyCtor>::value);
-
-  // Verify that types without them (i.e. nontrivial or deleted) are not.
-  EXPECT_FALSE(
-      absl::is_trivially_copy_constructible<NontrivialCopyCtor>::value);
-  EXPECT_FALSE(absl::is_trivially_copy_constructible<DeletedCopyCtor>::value);
-  EXPECT_FALSE(
-      absl::is_trivially_copy_constructible<MovableNonCopyable>::value);
-  EXPECT_FALSE(
-      absl::is_trivially_copy_constructible<NonCopyableOrMovable>::value);
-
-  // type with nontrivial destructor are nontrivial copy construbtible
-  EXPECT_FALSE(
-      absl::is_trivially_copy_constructible<NontrivialDestructor>::value);
-
-  // types with vtables
-  EXPECT_FALSE(absl::is_trivially_copy_constructible<Base>::value);
-
-  // Verify that simple_pair of such types is trivially copy constructible
-  EXPECT_TRUE(
-      (absl::is_trivially_copy_constructible<simple_pair<int, char*>>::value));
-  EXPECT_TRUE((
-      absl::is_trivially_copy_constructible<simple_pair<int, Trivial>>::value));
-  EXPECT_TRUE((absl::is_trivially_copy_constructible<
-               simple_pair<int, TrivialCopyCtor>>::value));
-
-  // Verify that types without trivial copy constructors are
-  // correctly marked as such.
-  EXPECT_FALSE(absl::is_trivially_copy_constructible<std::string>::value);
-  EXPECT_FALSE(absl::is_trivially_copy_constructible<std::vector<int>>::value);
-
-  // Verify that simple_pairs of types without trivial copy constructors
-  // are not marked as trivial.
-  EXPECT_FALSE((absl::is_trivially_copy_constructible<
-                simple_pair<int, std::string>>::value));
-  EXPECT_FALSE((absl::is_trivially_copy_constructible<
-                simple_pair<std::string, int>>::value));
-
-  // Verify that arrays are not
-  using int10 = int[10];
-  EXPECT_FALSE(absl::is_trivially_copy_constructible<int10>::value);
-}
-
-TEST(TypeTraitsTest, TestTrivialMoveAssign) {
-  // Verify that arithmetic types and pointers have trivial move
-  // assignment operators.
-  EXPECT_TRUE(absl::is_trivially_move_assignable<bool>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<char>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<unsigned char>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<signed char>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<wchar_t>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<int>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<unsigned int>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<int16_t>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<uint16_t>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<int64_t>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<uint64_t>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<float>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<double>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<long double>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<std::string*>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<Trivial*>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<const std::string*>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<const Trivial*>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<std::string**>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<Trivial**>::value);
-
-  // const qualified types are not assignable
-  EXPECT_FALSE(absl::is_trivially_move_assignable<const int>::value);
-
-  // types with compiler generated move assignment
-  EXPECT_TRUE(absl::is_trivially_move_assignable<Trivial>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<TrivialMoveAssign>::value);
-
-  // Verify that types without them (i.e. nontrivial or deleted) are not.
-  EXPECT_FALSE(absl::is_trivially_move_assignable<NontrivialCopyAssign>::value);
-  EXPECT_FALSE(absl::is_trivially_move_assignable<DeletedCopyAssign>::value);
-  EXPECT_FALSE(absl::is_trivially_move_assignable<NonCopyableOrMovable>::value);
-
-  // types with vtables
-  EXPECT_FALSE(absl::is_trivially_move_assignable<Base>::value);
-
-  // Verify that simple_pair is trivially assignable
-  EXPECT_TRUE(
-      (absl::is_trivially_move_assignable<simple_pair<int, char*>>::value));
-  EXPECT_TRUE(
-      (absl::is_trivially_move_assignable<simple_pair<int, Trivial>>::value));
-  EXPECT_TRUE((absl::is_trivially_move_assignable<
-               simple_pair<int, TrivialMoveAssign>>::value));
-
-  // Verify that types not trivially move assignable are
-  // correctly marked as such.
-  EXPECT_FALSE(absl::is_trivially_move_assignable<std::string>::value);
-  EXPECT_FALSE(absl::is_trivially_move_assignable<std::vector<int>>::value);
-
-  // Verify that simple_pairs of types not trivially move assignable
-  // are not marked as trivial.
-  EXPECT_FALSE((absl::is_trivially_move_assignable<
-                simple_pair<int, std::string>>::value));
-  EXPECT_FALSE((absl::is_trivially_move_assignable<
-                simple_pair<std::string, int>>::value));
-
-  // Verify that arrays are not trivially move assignable
-  using int10 = int[10];
-  EXPECT_FALSE(absl::is_trivially_move_assignable<int10>::value);
-
-  // Verify that references are handled correctly
-  EXPECT_TRUE(absl::is_trivially_move_assignable<Trivial&&>::value);
-  EXPECT_TRUE(absl::is_trivially_move_assignable<Trivial&>::value);
-}
-
-TEST(TypeTraitsTest, TestTrivialCopyAssign) {
-  // Verify that arithmetic types and pointers have trivial copy
-  // assignment operators.
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<bool>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<char>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<unsigned char>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<signed char>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<wchar_t>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<int>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<unsigned int>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<int16_t>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<uint16_t>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<int64_t>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<uint64_t>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<float>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<double>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<long double>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<std::string*>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<Trivial*>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<const std::string*>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<const Trivial*>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<std::string**>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<Trivial**>::value);
-
-  // const qualified types are not assignable
-  EXPECT_FALSE(absl::is_trivially_copy_assignable<const int>::value);
-
-  // types with compiler generated copy assignment
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<Trivial>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<TrivialCopyAssign>::value);
-
-  // Verify that types without them (i.e. nontrivial or deleted) are not.
-  EXPECT_FALSE(absl::is_trivially_copy_assignable<NontrivialCopyAssign>::value);
-  EXPECT_FALSE(absl::is_trivially_copy_assignable<DeletedCopyAssign>::value);
-  EXPECT_FALSE(absl::is_trivially_copy_assignable<MovableNonCopyable>::value);
-  EXPECT_FALSE(absl::is_trivially_copy_assignable<NonCopyableOrMovable>::value);
-
-  // types with vtables
-  EXPECT_FALSE(absl::is_trivially_copy_assignable<Base>::value);
-
-  // Verify that simple_pair is trivially assignable
-  EXPECT_TRUE(
-      (absl::is_trivially_copy_assignable<simple_pair<int, char*>>::value));
-  EXPECT_TRUE(
-      (absl::is_trivially_copy_assignable<simple_pair<int, Trivial>>::value));
-  EXPECT_TRUE((absl::is_trivially_copy_assignable<
-               simple_pair<int, TrivialCopyAssign>>::value));
-
-  // Verify that types not trivially copy assignable are
-  // correctly marked as such.
-  EXPECT_FALSE(absl::is_trivially_copy_assignable<std::string>::value);
-  EXPECT_FALSE(absl::is_trivially_copy_assignable<std::vector<int>>::value);
-
-  // Verify that simple_pairs of types not trivially copy assignable
-  // are not marked as trivial.
-  EXPECT_FALSE((absl::is_trivially_copy_assignable<
-                simple_pair<int, std::string>>::value));
-  EXPECT_FALSE((absl::is_trivially_copy_assignable<
-                simple_pair<std::string, int>>::value));
-
-  // Verify that arrays are not trivially copy assignable
-  using int10 = int[10];
-  EXPECT_FALSE(absl::is_trivially_copy_assignable<int10>::value);
-
-  // Verify that references are handled correctly
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<Trivial&&>::value);
-  EXPECT_TRUE(absl::is_trivially_copy_assignable<Trivial&>::value);
-}
-
-TEST(TypeTraitsTest, TestTriviallyCopyable) {
-  // Verify that arithmetic types and pointers are trivially copyable.
-  EXPECT_TRUE(absl::type_traits_internal::is_trivially_copyable<bool>::value);
-  EXPECT_TRUE(absl::type_traits_internal::is_trivially_copyable<char>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<unsigned char>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<signed char>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<wchar_t>::value);
-  EXPECT_TRUE(absl::type_traits_internal::is_trivially_copyable<int>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<unsigned int>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<int16_t>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<uint16_t>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<int64_t>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<uint64_t>::value);
-  EXPECT_TRUE(absl::type_traits_internal::is_trivially_copyable<float>::value);
-  EXPECT_TRUE(absl::type_traits_internal::is_trivially_copyable<double>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<long double>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<std::string*>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<Trivial*>::value);
-  EXPECT_TRUE(absl::type_traits_internal::is_trivially_copyable<
-              const std::string*>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<const Trivial*>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<std::string**>::value);
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<Trivial**>::value);
-
-  // const qualified types are not assignable but are constructible
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<const int>::value);
-
-  // Trivial copy constructor/assignment and destructor.
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<Trivial>::value);
-  // Trivial copy assignment, but non-trivial copy constructor/destructor.
-  EXPECT_FALSE(absl::type_traits_internal::is_trivially_copyable<
-               TrivialCopyAssign>::value);
-  // Trivial copy constructor, but non-trivial assignment.
-  EXPECT_FALSE(absl::type_traits_internal::is_trivially_copyable<
-               TrivialCopyCtor>::value);
-
-  // Types with a non-trivial copy constructor/assignment
-  EXPECT_FALSE(absl::type_traits_internal::is_trivially_copyable<
-               NontrivialCopyCtor>::value);
-  EXPECT_FALSE(absl::type_traits_internal::is_trivially_copyable<
-               NontrivialCopyAssign>::value);
-
-  // Types without copy constructor/assignment, but with move
-  // MSVC disagrees with other compilers about this:
-  // EXPECT_TRUE(absl::type_traits_internal::is_trivially_copyable<
-  //             MovableNonCopyable>::value);
-
-  // Types without copy/move constructor/assignment
-  EXPECT_FALSE(absl::type_traits_internal::is_trivially_copyable<
-               NonCopyableOrMovable>::value);
-
-  // No copy assign, but has trivial copy constructor.
-  EXPECT_TRUE(absl::type_traits_internal::is_trivially_copyable<
-              DeletedCopyAssign>::value);
-
-  // types with vtables
-  EXPECT_FALSE(absl::type_traits_internal::is_trivially_copyable<Base>::value);
-
-  // Verify that simple_pair is trivially copyable if members are
-  EXPECT_TRUE((absl::type_traits_internal::is_trivially_copyable<
-               simple_pair<int, char*>>::value));
-  EXPECT_TRUE((absl::type_traits_internal::is_trivially_copyable<
-               simple_pair<int, Trivial>>::value));
-
-  // Verify that types not trivially copyable are
-  // correctly marked as such.
-  EXPECT_FALSE(
-      absl::type_traits_internal::is_trivially_copyable<std::string>::value);
-  EXPECT_FALSE(absl::type_traits_internal::is_trivially_copyable<
-               std::vector<int>>::value);
-
-  // Verify that simple_pairs of types not trivially copyable
-  // are not marked as trivial.
-  EXPECT_FALSE((absl::type_traits_internal::is_trivially_copyable<
-                simple_pair<int, std::string>>::value));
-  EXPECT_FALSE((absl::type_traits_internal::is_trivially_copyable<
-                simple_pair<std::string, int>>::value));
-  EXPECT_FALSE((absl::type_traits_internal::is_trivially_copyable<
-                simple_pair<int, TrivialCopyAssign>>::value));
-
-  // Verify that arrays of trivially copyable types are trivially copyable
-  using int10 = int[10];
-  EXPECT_TRUE(absl::type_traits_internal::is_trivially_copyable<int10>::value);
-  using int10x10 = int[10][10];
-  EXPECT_TRUE(
-      absl::type_traits_internal::is_trivially_copyable<int10x10>::value);
-
-  // Verify that references are handled correctly
-  EXPECT_FALSE(
-      absl::type_traits_internal::is_trivially_copyable<Trivial&&>::value);
-  EXPECT_FALSE(
-      absl::type_traits_internal::is_trivially_copyable<Trivial&>::value);
-}
-
 TEST(TypeTraitsTest, TestRemoveCVRef) {
   EXPECT_TRUE(
       (std::is_same<typename absl::remove_cvref<int>::type, int>::value));
@@ -1241,82 +662,6 @@ TEST(TypeTraitsTest, TestResultOf) {
   EXPECT_EQ(TypeEnum::D, GetTypeExt(Wrap<TypeD>()));
 }
 
-template <typename T>
-bool TestCopyAssign() {
-  return absl::is_copy_assignable<T>::value ==
-         std::is_copy_assignable<T>::value;
-}
-
-TEST(TypeTraitsTest, IsCopyAssignable) {
-  EXPECT_TRUE(TestCopyAssign<int>());
-  EXPECT_TRUE(TestCopyAssign<int&>());
-  EXPECT_TRUE(TestCopyAssign<int&&>());
-
-  struct S {};
-  EXPECT_TRUE(TestCopyAssign<S>());
-  EXPECT_TRUE(TestCopyAssign<S&>());
-  EXPECT_TRUE(TestCopyAssign<S&&>());
-
-  class C {
-   public:
-    explicit C(C* c) : c_(c) {}
-    ~C() { delete c_; }
-
-   private:
-    C* c_;
-  };
-  EXPECT_TRUE(TestCopyAssign<C>());
-  EXPECT_TRUE(TestCopyAssign<C&>());
-  EXPECT_TRUE(TestCopyAssign<C&&>());
-
-  // Reason for ifndef: add_lvalue_reference<T> in libc++ breaks for these cases
-#ifndef _LIBCPP_VERSION
-  EXPECT_TRUE(TestCopyAssign<int()>());
-  EXPECT_TRUE(TestCopyAssign<int(int) const>());
-  EXPECT_TRUE(TestCopyAssign<int(...) volatile&>());
-  EXPECT_TRUE(TestCopyAssign<int(int, ...) const volatile&&>());
-#endif  // _LIBCPP_VERSION
-}
-
-template <typename T>
-bool TestMoveAssign() {
-  return absl::is_move_assignable<T>::value ==
-         std::is_move_assignable<T>::value;
-}
-
-TEST(TypeTraitsTest, IsMoveAssignable) {
-  EXPECT_TRUE(TestMoveAssign<int>());
-  EXPECT_TRUE(TestMoveAssign<int&>());
-  EXPECT_TRUE(TestMoveAssign<int&&>());
-
-  struct S {};
-  EXPECT_TRUE(TestMoveAssign<S>());
-  EXPECT_TRUE(TestMoveAssign<S&>());
-  EXPECT_TRUE(TestMoveAssign<S&&>());
-
-  class C {
-   public:
-    explicit C(C* c) : c_(c) {}
-    ~C() { delete c_; }
-    void operator=(const C&) = delete;
-    void operator=(C&&) = delete;
-
-   private:
-    C* c_;
-  };
-  EXPECT_TRUE(TestMoveAssign<C>());
-  EXPECT_TRUE(TestMoveAssign<C&>());
-  EXPECT_TRUE(TestMoveAssign<C&&>());
-
-  // Reason for ifndef: add_lvalue_reference<T> in libc++ breaks for these cases
-#ifndef _LIBCPP_VERSION
-  EXPECT_TRUE(TestMoveAssign<int()>());
-  EXPECT_TRUE(TestMoveAssign<int(int) const>());
-  EXPECT_TRUE(TestMoveAssign<int(...) volatile&>());
-  EXPECT_TRUE(TestMoveAssign<int(int, ...) const volatile&&>());
-#endif  // _LIBCPP_VERSION
-}
-
 namespace adl_namespace {
 
 struct DeletedSwap {