chore(3p/abseil_cpp): unvendor abseil_cpp r/3786

we weren't actually using these sources anymore, okay?

Change-Id: If701571d9716de308d3512e1eb22c35db0877a66
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5248
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: tazjin <tazjin@tvl.su>

4 files changed, 0 insertions, 825 deletions

diff --git a/third_party/abseil_cpp/absl/utility/BUILD.bazel b/third_party/abseil_cpp/absl/utility/BUILD.bazel
deleted file mode 100644
index 02b2c407f847..000000000000
--- a/third_party/abseil_cpp/absl/utility/BUILD.bazel
+++ /dev/null
@@ -1,55 +0,0 @@
-#
-# Copyright 2019 The Abseil Authors.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      https://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-
-load("@rules_cc//cc:defs.bzl", "cc_library", "cc_test")
-load(
-    "//absl:copts/configure_copts.bzl",
-    "ABSL_DEFAULT_COPTS",
-    "ABSL_DEFAULT_LINKOPTS",
-    "ABSL_TEST_COPTS",
-)
-
-package(default_visibility = ["//visibility:public"])
-
-licenses(["notice"])
-
-cc_library(
-    name = "utility",
-    hdrs = [
-        "utility.h",
-    ],
-    copts = ABSL_DEFAULT_COPTS,
-    linkopts = ABSL_DEFAULT_LINKOPTS,
-    deps = [
-        "//absl/base:base_internal",
-        "//absl/base:config",
-        "//absl/meta:type_traits",
-    ],
-)
-
-cc_test(
-    name = "utility_test",
-    srcs = ["utility_test.cc"],
-    copts = ABSL_TEST_COPTS,
-    linkopts = ABSL_DEFAULT_LINKOPTS,
-    deps = [
-        ":utility",
-        "//absl/base:core_headers",
-        "//absl/memory",
-        "//absl/strings",
-        "@com_google_googletest//:gtest_main",
-    ],
-)
diff --git a/third_party/abseil_cpp/absl/utility/CMakeLists.txt b/third_party/abseil_cpp/absl/utility/CMakeLists.txt
deleted file mode 100644
index e1edd19aa013..000000000000
--- a/third_party/abseil_cpp/absl/utility/CMakeLists.txt
+++ /dev/null
@@ -1,44 +0,0 @@
-#
-# Copyright 2017 The Abseil Authors.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      https://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-
-absl_cc_library(
-  NAME
-    utility
-  HDRS
-    "utility.h"
-  COPTS
-    ${ABSL_DEFAULT_COPTS}
-  DEPS
-    absl::base_internal
-    absl::config
-    absl::type_traits
-  PUBLIC
-)
-
-absl_cc_test(
-  NAME
-    utility_test
-  SRCS
-    "utility_test.cc"
-  COPTS
-    ${ABSL_TEST_COPTS}
-  DEPS
-    absl::utility
-    absl::core_headers
-    absl::memory
-    absl::strings
-    gmock_main
-)
diff --git a/third_party/abseil_cpp/absl/utility/utility.h b/third_party/abseil_cpp/absl/utility/utility.h
deleted file mode 100644
index bf9232209a9b..000000000000
--- a/third_party/abseil_cpp/absl/utility/utility.h
+++ /dev/null
@@ -1,350 +0,0 @@
-// Copyright 2017 The Abseil Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-// This header file contains C++11 versions of standard <utility> header
-// abstractions available within C++14 and C++17, and are designed to be drop-in
-// replacement for code compliant with C++14 and C++17.
-//
-// The following abstractions are defined:
-//
-//   * integer_sequence<T, Ints...>  == std::integer_sequence<T, Ints...>
-//   * index_sequence<Ints...>       == std::index_sequence<Ints...>
-//   * make_integer_sequence<T, N>   == std::make_integer_sequence<T, N>
-//   * make_index_sequence<N>        == std::make_index_sequence<N>
-//   * index_sequence_for<Ts...>     == std::index_sequence_for<Ts...>
-//   * apply<Functor, Tuple>         == std::apply<Functor, Tuple>
-//   * exchange<T>                   == std::exchange<T>
-//   * make_from_tuple<T>            == std::make_from_tuple<T>
-//
-// This header file also provides the tag types `in_place_t`, `in_place_type_t`,
-// and `in_place_index_t`, as well as the constant `in_place`, and
-// `constexpr` `std::move()` and `std::forward()` implementations in C++11.
-//
-// References:
-//
-//  https://en.cppreference.com/w/cpp/utility/integer_sequence
-//  https://en.cppreference.com/w/cpp/utility/apply
-//  http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3658.html
-
-#ifndef ABSL_UTILITY_UTILITY_H_
-#define ABSL_UTILITY_UTILITY_H_
-
-#include <cstddef>
-#include <cstdlib>
-#include <tuple>
-#include <utility>
-
-#include "absl/base/config.h"
-#include "absl/base/internal/inline_variable.h"
-#include "absl/base/internal/invoke.h"
-#include "absl/meta/type_traits.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-
-// integer_sequence
-//
-// Class template representing a compile-time integer sequence. An instantiation
-// of `integer_sequence<T, Ints...>` has a sequence of integers encoded in its
-// type through its template arguments (which is a common need when
-// working with C++11 variadic templates). `absl::integer_sequence` is designed
-// to be a drop-in replacement for C++14's `std::integer_sequence`.
-//
-// Example:
-//
-//   template< class T, T... Ints >
-//   void user_function(integer_sequence<T, Ints...>);
-//
-//   int main()
-//   {
-//     // user_function's `T` will be deduced to `int` and `Ints...`
-//     // will be deduced to `0, 1, 2, 3, 4`.
-//     user_function(make_integer_sequence<int, 5>());
-//   }
-template <typename T, T... Ints>
-struct integer_sequence {
-  using value_type = T;
-  static constexpr size_t size() noexcept { return sizeof...(Ints); }
-};
-
-// index_sequence
-//
-// A helper template for an `integer_sequence` of `size_t`,
-// `absl::index_sequence` is designed to be a drop-in replacement for C++14's
-// `std::index_sequence`.
-template <size_t... Ints>
-using index_sequence = integer_sequence<size_t, Ints...>;
-
-namespace utility_internal {
-
-template <typename Seq, size_t SeqSize, size_t Rem>
-struct Extend;
-
-// Note that SeqSize == sizeof...(Ints). It's passed explicitly for efficiency.
-template <typename T, T... Ints, size_t SeqSize>
-struct Extend<integer_sequence<T, Ints...>, SeqSize, 0> {
-  using type = integer_sequence<T, Ints..., (Ints + SeqSize)...>;
-};
-
-template <typename T, T... Ints, size_t SeqSize>
-struct Extend<integer_sequence<T, Ints...>, SeqSize, 1> {
-  using type = integer_sequence<T, Ints..., (Ints + SeqSize)..., 2 * SeqSize>;
-};
-
-// Recursion helper for 'make_integer_sequence<T, N>'.
-// 'Gen<T, N>::type' is an alias for 'integer_sequence<T, 0, 1, ... N-1>'.
-template <typename T, size_t N>
-struct Gen {
-  using type =
-      typename Extend<typename Gen<T, N / 2>::type, N / 2, N % 2>::type;
-};
-
-template <typename T>
-struct Gen<T, 0> {
-  using type = integer_sequence<T>;
-};
-
-template <typename T>
-struct InPlaceTypeTag {
-  explicit InPlaceTypeTag() = delete;
-  InPlaceTypeTag(const InPlaceTypeTag&) = delete;
-  InPlaceTypeTag& operator=(const InPlaceTypeTag&) = delete;
-};
-
-template <size_t I>
-struct InPlaceIndexTag {
-  explicit InPlaceIndexTag() = delete;
-  InPlaceIndexTag(const InPlaceIndexTag&) = delete;
-  InPlaceIndexTag& operator=(const InPlaceIndexTag&) = delete;
-};
-
-}  // namespace utility_internal
-
-// Compile-time sequences of integers
-
-// make_integer_sequence
-//
-// This template alias is equivalent to
-// `integer_sequence<int, 0, 1, ..., N-1>`, and is designed to be a drop-in
-// replacement for C++14's `std::make_integer_sequence`.
-template <typename T, T N>
-using make_integer_sequence = typename utility_internal::Gen<T, N>::type;
-
-// make_index_sequence
-//
-// This template alias is equivalent to `index_sequence<0, 1, ..., N-1>`,
-// and is designed to be a drop-in replacement for C++14's
-// `std::make_index_sequence`.
-template <size_t N>
-using make_index_sequence = make_integer_sequence<size_t, N>;
-
-// index_sequence_for
-//
-// Converts a typename pack into an index sequence of the same length, and
-// is designed to be a drop-in replacement for C++14's
-// `std::index_sequence_for()`
-template <typename... Ts>
-using index_sequence_for = make_index_sequence<sizeof...(Ts)>;
-
-// Tag types
-
-#ifdef ABSL_USES_STD_OPTIONAL
-
-using std::in_place_t;
-using std::in_place;
-
-#else  // ABSL_USES_STD_OPTIONAL
-
-// in_place_t
-//
-// Tag type used to specify in-place construction, such as with
-// `absl::optional`, designed to be a drop-in replacement for C++17's
-// `std::in_place_t`.
-struct in_place_t {};
-
-ABSL_INTERNAL_INLINE_CONSTEXPR(in_place_t, in_place, {});
-
-#endif  // ABSL_USES_STD_OPTIONAL
-
-#if defined(ABSL_USES_STD_ANY) || defined(ABSL_USES_STD_VARIANT)
-using std::in_place_type;
-using std::in_place_type_t;
-#else
-
-// in_place_type_t
-//
-// Tag type used for in-place construction when the type to construct needs to
-// be specified, such as with `absl::any`, designed to be a drop-in replacement
-// for C++17's `std::in_place_type_t`.
-template <typename T>
-using in_place_type_t = void (*)(utility_internal::InPlaceTypeTag<T>);
-
-template <typename T>
-void in_place_type(utility_internal::InPlaceTypeTag<T>) {}
-#endif  // ABSL_USES_STD_ANY || ABSL_USES_STD_VARIANT
-
-#ifdef ABSL_USES_STD_VARIANT
-using std::in_place_index;
-using std::in_place_index_t;
-#else
-
-// in_place_index_t
-//
-// Tag type used for in-place construction when the type to construct needs to
-// be specified, such as with `absl::any`, designed to be a drop-in replacement
-// for C++17's `std::in_place_index_t`.
-template <size_t I>
-using in_place_index_t = void (*)(utility_internal::InPlaceIndexTag<I>);
-
-template <size_t I>
-void in_place_index(utility_internal::InPlaceIndexTag<I>) {}
-#endif  // ABSL_USES_STD_VARIANT
-
-// Constexpr move and forward
-
-// move()
-//
-// A constexpr version of `std::move()`, designed to be a drop-in replacement
-// for C++14's `std::move()`.
-template <typename T>
-constexpr absl::remove_reference_t<T>&& move(T&& t) noexcept {
-  return static_cast<absl::remove_reference_t<T>&&>(t);
-}
-
-// forward()
-//
-// A constexpr version of `std::forward()`, designed to be a drop-in replacement
-// for C++14's `std::forward()`.
-template <typename T>
-constexpr T&& forward(
-    absl::remove_reference_t<T>& t) noexcept {  // NOLINT(runtime/references)
-  return static_cast<T&&>(t);
-}
-
-namespace utility_internal {
-// Helper method for expanding tuple into a called method.
-template <typename Functor, typename Tuple, std::size_t... Indexes>
-auto apply_helper(Functor&& functor, Tuple&& t, index_sequence<Indexes...>)
-    -> decltype(absl::base_internal::invoke(
-        absl::forward<Functor>(functor),
-        std::get<Indexes>(absl::forward<Tuple>(t))...)) {
-  return absl::base_internal::invoke(
-      absl::forward<Functor>(functor),
-      std::get<Indexes>(absl::forward<Tuple>(t))...);
-}
-
-}  // namespace utility_internal
-
-// apply
-//
-// Invokes a Callable using elements of a tuple as its arguments.
-// Each element of the tuple corresponds to an argument of the call (in order).
-// Both the Callable argument and the tuple argument are perfect-forwarded.
-// For member-function Callables, the first tuple element acts as the `this`
-// pointer. `absl::apply` is designed to be a drop-in replacement for C++17's
-// `std::apply`. Unlike C++17's `std::apply`, this is not currently `constexpr`.
-//
-// Example:
-//
-//   class Foo {
-//    public:
-//     void Bar(int);
-//   };
-//   void user_function1(int, std::string);
-//   void user_function2(std::unique_ptr<Foo>);
-//   auto user_lambda = [](int, int) {};
-//
-//   int main()
-//   {
-//       std::tuple<int, std::string> tuple1(42, "bar");
-//       // Invokes the first user function on int, std::string.
-//       absl::apply(&user_function1, tuple1);
-//
-//       std::tuple<std::unique_ptr<Foo>> tuple2(absl::make_unique<Foo>());
-//       // Invokes the user function that takes ownership of the unique
-//       // pointer.
-//       absl::apply(&user_function2, std::move(tuple2));
-//
-//       auto foo = absl::make_unique<Foo>();
-//       std::tuple<Foo*, int> tuple3(foo.get(), 42);
-//       // Invokes the method Bar on foo with one argument, 42.
-//       absl::apply(&Foo::Bar, tuple3);
-//
-//       std::tuple<int, int> tuple4(8, 9);
-//       // Invokes a lambda.
-//       absl::apply(user_lambda, tuple4);
-//   }
-template <typename Functor, typename Tuple>
-auto apply(Functor&& functor, Tuple&& t)
-    -> decltype(utility_internal::apply_helper(
-        absl::forward<Functor>(functor), absl::forward<Tuple>(t),
-        absl::make_index_sequence<std::tuple_size<
-            typename std::remove_reference<Tuple>::type>::value>{})) {
-  return utility_internal::apply_helper(
-      absl::forward<Functor>(functor), absl::forward<Tuple>(t),
-      absl::make_index_sequence<std::tuple_size<
-          typename std::remove_reference<Tuple>::type>::value>{});
-}
-
-// exchange
-//
-// Replaces the value of `obj` with `new_value` and returns the old value of
-// `obj`.  `absl::exchange` is designed to be a drop-in replacement for C++14's
-// `std::exchange`.
-//
-// Example:
-//
-//   Foo& operator=(Foo&& other) {
-//     ptr1_ = absl::exchange(other.ptr1_, nullptr);
-//     int1_ = absl::exchange(other.int1_, -1);
-//     return *this;
-//   }
-template <typename T, typename U = T>
-T exchange(T& obj, U&& new_value) {
-  T old_value = absl::move(obj);
-  obj = absl::forward<U>(new_value);
-  return old_value;
-}
-
-namespace utility_internal {
-template <typename T, typename Tuple, size_t... I>
-T make_from_tuple_impl(Tuple&& tup, absl::index_sequence<I...>) {
-  return T(std::get<I>(std::forward<Tuple>(tup))...);
-}
-}  // namespace utility_internal
-
-// make_from_tuple
-//
-// Given the template parameter type `T` and a tuple of arguments
-// `std::tuple(arg0, arg1, ..., argN)` constructs an object of type `T` as if by
-// calling `T(arg0, arg1, ..., argN)`.
-//
-// Example:
-//
-//   std::tuple<const char*, size_t> args("hello world", 5);
-//   auto s = absl::make_from_tuple<std::string>(args);
-//   assert(s == "hello");
-//
-template <typename T, typename Tuple>
-constexpr T make_from_tuple(Tuple&& tup) {
-  return utility_internal::make_from_tuple_impl<T>(
-      std::forward<Tuple>(tup),
-      absl::make_index_sequence<
-          std::tuple_size<absl::decay_t<Tuple>>::value>{});
-}
-
-ABSL_NAMESPACE_END
-}  // namespace absl
-
-#endif  // ABSL_UTILITY_UTILITY_H_
diff --git a/third_party/abseil_cpp/absl/utility/utility_test.cc b/third_party/abseil_cpp/absl/utility/utility_test.cc
deleted file mode 100644
index f044ad644a4d..000000000000
--- a/third_party/abseil_cpp/absl/utility/utility_test.cc
+++ /dev/null
@@ -1,376 +0,0 @@
-// Copyright 2017 The Abseil Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#include "absl/utility/utility.h"
-
-#include <sstream>
-#include <string>
-#include <tuple>
-#include <type_traits>
-#include <vector>
-
-#include "gmock/gmock.h"
-#include "gtest/gtest.h"
-#include "absl/base/attributes.h"
-#include "absl/memory/memory.h"
-#include "absl/strings/str_cat.h"
-
-namespace {
-
-#ifdef _MSC_VER
-// Warnings for unused variables in this test are false positives.  On other
-// platforms, they are suppressed by ABSL_ATTRIBUTE_UNUSED, but that doesn't
-// work on MSVC.
-// Both the unused variables and the name length warnings are due to calls
-// to absl::make_index_sequence with very large values, creating very long type
-// names. The resulting warnings are so long they make build output unreadable.
-#pragma warning( push )
-#pragma warning( disable : 4503 )  // decorated name length exceeded
-#pragma warning( disable : 4101 )  // unreferenced local variable
-#endif  // _MSC_VER
-
-using ::testing::ElementsAre;
-using ::testing::Pointee;
-using ::testing::StaticAssertTypeEq;
-
-TEST(IntegerSequenceTest, ValueType) {
-  StaticAssertTypeEq<int, absl::integer_sequence<int>::value_type>();
-  StaticAssertTypeEq<char, absl::integer_sequence<char>::value_type>();
-}
-
-TEST(IntegerSequenceTest, Size) {
-  EXPECT_EQ(0, (absl::integer_sequence<int>::size()));
-  EXPECT_EQ(1, (absl::integer_sequence<int, 0>::size()));
-  EXPECT_EQ(1, (absl::integer_sequence<int, 1>::size()));
-  EXPECT_EQ(2, (absl::integer_sequence<int, 1, 2>::size()));
-  EXPECT_EQ(3, (absl::integer_sequence<int, 0, 1, 2>::size()));
-  EXPECT_EQ(3, (absl::integer_sequence<int, -123, 123, 456>::size()));
-  constexpr size_t sz = absl::integer_sequence<int, 0, 1>::size();
-  EXPECT_EQ(2, sz);
-}
-
-TEST(IntegerSequenceTest, MakeIndexSequence) {
-  StaticAssertTypeEq<absl::index_sequence<>, absl::make_index_sequence<0>>();
-  StaticAssertTypeEq<absl::index_sequence<0>, absl::make_index_sequence<1>>();
-  StaticAssertTypeEq<absl::index_sequence<0, 1>,
-                     absl::make_index_sequence<2>>();
-  StaticAssertTypeEq<absl::index_sequence<0, 1, 2>,
-                     absl::make_index_sequence<3>>();
-}
-
-TEST(IntegerSequenceTest, MakeIntegerSequence) {
-  StaticAssertTypeEq<absl::integer_sequence<int>,
-                     absl::make_integer_sequence<int, 0>>();
-  StaticAssertTypeEq<absl::integer_sequence<int, 0>,
-                     absl::make_integer_sequence<int, 1>>();
-  StaticAssertTypeEq<absl::integer_sequence<int, 0, 1>,
-                     absl::make_integer_sequence<int, 2>>();
-  StaticAssertTypeEq<absl::integer_sequence<int, 0, 1, 2>,
-                     absl::make_integer_sequence<int, 3>>();
-}
-
-template <typename... Ts>
-class Counter {};
-
-template <size_t... Is>
-void CountAll(absl::index_sequence<Is...>) {
-  // We only need an alias here, but instantiate a variable to silence warnings
-  // for unused typedefs in some compilers.
-  ABSL_ATTRIBUTE_UNUSED Counter<absl::make_index_sequence<Is>...> seq;
-}
-
-// This test verifies that absl::make_index_sequence can handle large arguments
-// without blowing up template instantiation stack, going OOM or taking forever
-// to compile (there is hard 15 minutes limit imposed by forge).
-TEST(IntegerSequenceTest, MakeIndexSequencePerformance) {
-  // O(log N) template instantiations.
-  // We only need an alias here, but instantiate a variable to silence warnings
-  // for unused typedefs in some compilers.
-  ABSL_ATTRIBUTE_UNUSED absl::make_index_sequence<(1 << 16) - 1> seq;
-  // O(N) template instantiations.
-  CountAll(absl::make_index_sequence<(1 << 8) - 1>());
-}
-
-template <typename F, typename Tup, size_t... Is>
-auto ApplyFromTupleImpl(F f, const Tup& tup, absl::index_sequence<Is...>)
-    -> decltype(f(std::get<Is>(tup)...)) {
-  return f(std::get<Is>(tup)...);
-}
-
-template <typename Tup>
-using TupIdxSeq = absl::make_index_sequence<std::tuple_size<Tup>::value>;
-
-template <typename F, typename Tup>
-auto ApplyFromTuple(F f, const Tup& tup)
-    -> decltype(ApplyFromTupleImpl(f, tup, TupIdxSeq<Tup>{})) {
-  return ApplyFromTupleImpl(f, tup, TupIdxSeq<Tup>{});
-}
-
-template <typename T>
-std::string Fmt(const T& x) {
-  std::ostringstream os;
-  os << x;
-  return os.str();
-}
-
-struct PoorStrCat {
-  template <typename... Args>
-  std::string operator()(const Args&... args) const {
-    std::string r;
-    for (const auto& e : {Fmt(args)...}) r += e;
-    return r;
-  }
-};
-
-template <typename Tup, size_t... Is>
-std::vector<std::string> TupStringVecImpl(const Tup& tup,
-                                          absl::index_sequence<Is...>) {
-  return {Fmt(std::get<Is>(tup))...};
-}
-
-template <typename... Ts>
-std::vector<std::string> TupStringVec(const std::tuple<Ts...>& tup) {
-  return TupStringVecImpl(tup, absl::index_sequence_for<Ts...>());
-}
-
-TEST(MakeIndexSequenceTest, ApplyFromTupleExample) {
-  PoorStrCat f{};
-  EXPECT_EQ("12abc3.14", f(12, "abc", 3.14));
-  EXPECT_EQ("12abc3.14", ApplyFromTuple(f, std::make_tuple(12, "abc", 3.14)));
-}
-
-TEST(IndexSequenceForTest, Basic) {
-  StaticAssertTypeEq<absl::index_sequence<>, absl::index_sequence_for<>>();
-  StaticAssertTypeEq<absl::index_sequence<0>, absl::index_sequence_for<int>>();
-  StaticAssertTypeEq<absl::index_sequence<0, 1, 2, 3>,
-                     absl::index_sequence_for<int, void, char, int>>();
-}
-
-TEST(IndexSequenceForTest, Example) {
-  EXPECT_THAT(TupStringVec(std::make_tuple(12, "abc", 3.14)),
-              ElementsAre("12", "abc", "3.14"));
-}
-
-int Function(int a, int b) { return a - b; }
-
-int Sink(std::unique_ptr<int> p) { return *p; }
-
-std::unique_ptr<int> Factory(int n) { return absl::make_unique<int>(n); }
-
-void NoOp() {}
-
-struct ConstFunctor {
-  int operator()(int a, int b) const { return a - b; }
-};
-
-struct MutableFunctor {
-  int operator()(int a, int b) { return a - b; }
-};
-
-struct EphemeralFunctor {
-  EphemeralFunctor() {}
-  EphemeralFunctor(const EphemeralFunctor&) {}
-  EphemeralFunctor(EphemeralFunctor&&) {}
-  int operator()(int a, int b) && { return a - b; }
-};
-
-struct OverloadedFunctor {
-  OverloadedFunctor() {}
-  OverloadedFunctor(const OverloadedFunctor&) {}
-  OverloadedFunctor(OverloadedFunctor&&) {}
-  template <typename... Args>
-  std::string operator()(const Args&... args) & {
-    return absl::StrCat("&", args...);
-  }
-  template <typename... Args>
-  std::string operator()(const Args&... args) const& {
-    return absl::StrCat("const&", args...);
-  }
-  template <typename... Args>
-  std::string operator()(const Args&... args) && {
-    return absl::StrCat("&&", args...);
-  }
-};
-
-struct Class {
-  int Method(int a, int b) { return a - b; }
-  int ConstMethod(int a, int b) const { return a - b; }
-
-  int member;
-};
-
-struct FlipFlop {
-  int ConstMethod() const { return member; }
-  FlipFlop operator*() const { return {-member}; }
-
-  int member;
-};
-
-TEST(ApplyTest, Function) {
-  EXPECT_EQ(1, absl::apply(Function, std::make_tuple(3, 2)));
-  EXPECT_EQ(1, absl::apply(&Function, std::make_tuple(3, 2)));
-}
-
-TEST(ApplyTest, NonCopyableArgument) {
-  EXPECT_EQ(42, absl::apply(Sink, std::make_tuple(absl::make_unique<int>(42))));
-}
-
-TEST(ApplyTest, NonCopyableResult) {
-  EXPECT_THAT(absl::apply(Factory, std::make_tuple(42)),
-              ::testing::Pointee(42));
-}
-
-TEST(ApplyTest, VoidResult) { absl::apply(NoOp, std::tuple<>()); }
-
-TEST(ApplyTest, ConstFunctor) {
-  EXPECT_EQ(1, absl::apply(ConstFunctor(), std::make_tuple(3, 2)));
-}
-
-TEST(ApplyTest, MutableFunctor) {
-  MutableFunctor f;
-  EXPECT_EQ(1, absl::apply(f, std::make_tuple(3, 2)));
-  EXPECT_EQ(1, absl::apply(MutableFunctor(), std::make_tuple(3, 2)));
-}
-TEST(ApplyTest, EphemeralFunctor) {
-  EphemeralFunctor f;
-  EXPECT_EQ(1, absl::apply(std::move(f), std::make_tuple(3, 2)));
-  EXPECT_EQ(1, absl::apply(EphemeralFunctor(), std::make_tuple(3, 2)));
-}
-TEST(ApplyTest, OverloadedFunctor) {
-  OverloadedFunctor f;
-  const OverloadedFunctor& cf = f;
-
-  EXPECT_EQ("&", absl::apply(f, std::tuple<>{}));
-  EXPECT_EQ("& 42", absl::apply(f, std::make_tuple(" 42")));
-
-  EXPECT_EQ("const&", absl::apply(cf, std::tuple<>{}));
-  EXPECT_EQ("const& 42", absl::apply(cf, std::make_tuple(" 42")));
-
-  EXPECT_EQ("&&", absl::apply(std::move(f), std::tuple<>{}));
-  OverloadedFunctor f2;
-  EXPECT_EQ("&& 42", absl::apply(std::move(f2), std::make_tuple(" 42")));
-}
-
-TEST(ApplyTest, ReferenceWrapper) {
-  ConstFunctor cf;
-  MutableFunctor mf;
-  EXPECT_EQ(1, absl::apply(std::cref(cf), std::make_tuple(3, 2)));
-  EXPECT_EQ(1, absl::apply(std::ref(cf), std::make_tuple(3, 2)));
-  EXPECT_EQ(1, absl::apply(std::ref(mf), std::make_tuple(3, 2)));
-}
-
-TEST(ApplyTest, MemberFunction) {
-  std::unique_ptr<Class> p(new Class);
-  std::unique_ptr<const Class> cp(new Class);
-  EXPECT_EQ(
-      1, absl::apply(&Class::Method,
-                     std::tuple<std::unique_ptr<Class>&, int, int>(p, 3, 2)));
-  EXPECT_EQ(1, absl::apply(&Class::Method,
-                           std::tuple<Class*, int, int>(p.get(), 3, 2)));
-  EXPECT_EQ(
-      1, absl::apply(&Class::Method, std::tuple<Class&, int, int>(*p, 3, 2)));
-
-  EXPECT_EQ(
-      1, absl::apply(&Class::ConstMethod,
-                     std::tuple<std::unique_ptr<Class>&, int, int>(p, 3, 2)));
-  EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
-                           std::tuple<Class*, int, int>(p.get(), 3, 2)));
-  EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
-                           std::tuple<Class&, int, int>(*p, 3, 2)));
-
-  EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
-                           std::tuple<std::unique_ptr<const Class>&, int, int>(
-                               cp, 3, 2)));
-  EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
-                           std::tuple<const Class*, int, int>(cp.get(), 3, 2)));
-  EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
-                           std::tuple<const Class&, int, int>(*cp, 3, 2)));
-
-  EXPECT_EQ(1, absl::apply(&Class::Method,
-                           std::make_tuple(absl::make_unique<Class>(), 3, 2)));
-  EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
-                           std::make_tuple(absl::make_unique<Class>(), 3, 2)));
-  EXPECT_EQ(
-      1, absl::apply(&Class::ConstMethod,
-                     std::make_tuple(absl::make_unique<const Class>(), 3, 2)));
-}
-
-TEST(ApplyTest, DataMember) {
-  std::unique_ptr<Class> p(new Class{42});
-  std::unique_ptr<const Class> cp(new Class{42});
-  EXPECT_EQ(
-      42, absl::apply(&Class::member, std::tuple<std::unique_ptr<Class>&>(p)));
-  EXPECT_EQ(42, absl::apply(&Class::member, std::tuple<Class&>(*p)));
-  EXPECT_EQ(42, absl::apply(&Class::member, std::tuple<Class*>(p.get())));
-
-  absl::apply(&Class::member, std::tuple<std::unique_ptr<Class>&>(p)) = 42;
-  absl::apply(&Class::member, std::tuple<Class*>(p.get())) = 42;
-  absl::apply(&Class::member, std::tuple<Class&>(*p)) = 42;
-
-  EXPECT_EQ(42, absl::apply(&Class::member,
-                            std::tuple<std::unique_ptr<const Class>&>(cp)));
-  EXPECT_EQ(42, absl::apply(&Class::member, std::tuple<const Class&>(*cp)));
-  EXPECT_EQ(42,
-            absl::apply(&Class::member, std::tuple<const Class*>(cp.get())));
-}
-
-TEST(ApplyTest, FlipFlop) {
-  FlipFlop obj = {42};
-  // This call could resolve to (obj.*&FlipFlop::ConstMethod)() or
-  // ((*obj).*&FlipFlop::ConstMethod)(). We verify that it's the former.
-  EXPECT_EQ(42, absl::apply(&FlipFlop::ConstMethod, std::make_tuple(obj)));
-  EXPECT_EQ(42, absl::apply(&FlipFlop::member, std::make_tuple(obj)));
-}
-
-TEST(ExchangeTest, MoveOnly) {
-  auto a = Factory(1);
-  EXPECT_EQ(1, *a);
-  auto b = absl::exchange(a, Factory(2));
-  EXPECT_EQ(2, *a);
-  EXPECT_EQ(1, *b);
-}
-
-TEST(MakeFromTupleTest, String) {
-  EXPECT_EQ(
-      absl::make_from_tuple<std::string>(std::make_tuple("hello world", 5)),
-      "hello");
-}
-
-TEST(MakeFromTupleTest, MoveOnlyParameter) {
-  struct S {
-    S(std::unique_ptr<int> n, std::unique_ptr<int> m) : value(*n + *m) {}
-    int value = 0;
-  };
-  auto tup =
-      std::make_tuple(absl::make_unique<int>(3), absl::make_unique<int>(4));
-  auto s = absl::make_from_tuple<S>(std::move(tup));
-  EXPECT_EQ(s.value, 7);
-}
-
-TEST(MakeFromTupleTest, NoParameters) {
-  struct S {
-    S() : value(1) {}
-    int value = 2;
-  };
-  EXPECT_EQ(absl::make_from_tuple<S>(std::make_tuple()).value, 1);
-}
-
-TEST(MakeFromTupleTest, Pair) {
-  EXPECT_EQ(
-      (absl::make_from_tuple<std::pair<bool, int>>(std::make_tuple(true, 17))),
-      std::make_pair(true, 17));
-}
-
-}  // namespace
-