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diff --git a/third_party/abseil_cpp/absl/utility/utility_test.cc b/third_party/abseil_cpp/absl/utility/utility_test.cc
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+++ b/third_party/abseil_cpp/absl/utility/utility_test.cc
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+// 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
+