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-rw-r--r--third_party/abseil_cpp/absl/status/BUILD.bazel103
-rw-r--r--third_party/abseil_cpp/absl/status/CMakeLists.txt88
-rw-r--r--third_party/abseil_cpp/absl/status/internal/status_internal.h58
-rw-r--r--third_party/abseil_cpp/absl/status/internal/statusor_internal.h396
-rw-r--r--third_party/abseil_cpp/absl/status/status.cc442
-rw-r--r--third_party/abseil_cpp/absl/status/status.h817
-rw-r--r--third_party/abseil_cpp/absl/status/status_payload_printer.cc38
-rw-r--r--third_party/abseil_cpp/absl/status/status_payload_printer.h51
-rw-r--r--third_party/abseil_cpp/absl/status/status_test.cc458
-rw-r--r--third_party/abseil_cpp/absl/status/statusor.cc71
-rw-r--r--third_party/abseil_cpp/absl/status/statusor.h760
-rw-r--r--third_party/abseil_cpp/absl/status/statusor_internals.h250
-rw-r--r--third_party/abseil_cpp/absl/status/statusor_test.cc1811
13 files changed, 5343 insertions, 0 deletions
diff --git a/third_party/abseil_cpp/absl/status/BUILD.bazel b/third_party/abseil_cpp/absl/status/BUILD.bazel
new file mode 100644
index 000000000000..189bd73d0e46
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/BUILD.bazel
@@ -0,0 +1,103 @@
+#
+# 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 package contains `absl::Status`.
+# It will expand later to have utilities around `Status` like `StatusOr`,
+# `StatusBuilder` and macros.
+
+load("@rules_cc//cc:defs.bzl", "cc_library", "cc_test")
+load(
+    "//absl:copts/configure_copts.bzl",
+    "ABSL_DEFAULT_COPTS",
+    "ABSL_TEST_COPTS",
+)
+
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])
+
+cc_library(
+    name = "status",
+    srcs = [
+        "internal/status_internal.h",
+        "status.cc",
+        "status_payload_printer.cc",
+    ],
+    hdrs = [
+        "status.h",
+        "status_payload_printer.h",
+    ],
+    copts = ABSL_DEFAULT_COPTS,
+    deps = [
+        "//absl/base:atomic_hook",
+        "//absl/base:config",
+        "//absl/base:core_headers",
+        "//absl/base:raw_logging_internal",
+        "//absl/container:inlined_vector",
+        "//absl/debugging:stacktrace",
+        "//absl/debugging:symbolize",
+        "//absl/strings",
+        "//absl/strings:cord",
+        "//absl/strings:str_format",
+        "//absl/types:optional",
+    ],
+)
+
+cc_test(
+    name = "status_test",
+    srcs = ["status_test.cc"],
+    copts = ABSL_TEST_COPTS,
+    deps = [
+        ":status",
+        "//absl/strings",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
+cc_library(
+    name = "statusor",
+    srcs = [
+        "internal/statusor_internal.h",
+        "statusor.cc",
+    ],
+    hdrs = [
+        "statusor.h",
+    ],
+    copts = ABSL_DEFAULT_COPTS,
+    deps = [
+        ":status",
+        "//absl/base:core_headers",
+        "//absl/base:raw_logging_internal",
+        "//absl/meta:type_traits",
+        "//absl/strings",
+        "//absl/types:variant",
+        "//absl/utility",
+    ],
+)
+
+cc_test(
+    name = "statusor_test",
+    size = "small",
+    srcs = ["statusor_test.cc"],
+    deps = [
+        ":status",
+        ":statusor",
+        "//absl/base",
+        "//absl/memory",
+        "//absl/types:any",
+        "//absl/utility",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
diff --git a/third_party/abseil_cpp/absl/status/CMakeLists.txt b/third_party/abseil_cpp/absl/status/CMakeLists.txt
new file mode 100644
index 000000000000..f0d798a3732d
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/CMakeLists.txt
@@ -0,0 +1,88 @@
+#
+# Copyright 2020 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
+    status
+  HDRS
+    "status.h"
+  SRCS
+    "internal/status_internal.h"
+    "status.cc"
+    "status_payload_printer.h"
+    "status_payload_printer.cc"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::atomic_hook
+    absl::config
+    absl::core_headers
+    absl::raw_logging_internal
+    absl::inlined_vector
+    absl::stacktrace
+    absl::symbolize
+    absl::strings
+    absl::cord
+    absl::str_format
+    absl::optional
+  PUBLIC
+)
+
+absl_cc_test(
+  NAME
+    status_test
+  SRCS
+   "status_test.cc"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  DEPS
+    absl::status
+    absl::strings
+    gmock_main
+)
+
+absl_cc_library(
+  NAME
+    statusor
+  HDRS
+    "statusor.h"
+  SRCS
+    "statusor.cc"
+    "internal/statusor_internal.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::status
+    absl::core_headers
+    absl::raw_logging_internal
+    absl::type_traits
+    absl::strings
+    absl::utility
+    absl::variant
+  PUBLIC
+)
+
+absl_cc_test(
+  NAME
+    statusor_test
+  SRCS
+   "statusor_test.cc"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  DEPS
+    absl::status
+    absl::statusor
+    gmock_main
+)
diff --git a/third_party/abseil_cpp/absl/status/internal/status_internal.h b/third_party/abseil_cpp/absl/status/internal/status_internal.h
new file mode 100644
index 000000000000..279f8f55bef0
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/internal/status_internal.h
@@ -0,0 +1,58 @@
+// 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.
+#ifndef ABSL_STATUS_INTERNAL_STATUS_INTERNAL_H_
+#define ABSL_STATUS_INTERNAL_STATUS_INTERNAL_H_
+
+#include <string>
+
+#include "absl/container/inlined_vector.h"
+#include "absl/strings/cord.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+
+enum class StatusCode : int;
+
+namespace status_internal {
+
+// Container for status payloads.
+struct Payload {
+  std::string type_url;
+  absl::Cord payload;
+};
+
+using Payloads = absl::InlinedVector<Payload, 1>;
+
+// Reference-counted representation of Status data.
+struct StatusRep {
+  StatusRep(absl::StatusCode code, std::string message,
+            std::unique_ptr<status_internal::Payloads> payloads)
+      : ref(int32_t{1}),
+        code(code),
+        message(std::move(message)),
+        payloads(std::move(payloads)) {}
+
+  std::atomic<int32_t> ref;
+  absl::StatusCode code;
+  std::string message;
+  std::unique_ptr<status_internal::Payloads> payloads;
+};
+
+absl::StatusCode MapToLocalCode(int value);
+}  // namespace status_internal
+
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_STATUS_INTERNAL_STATUS_INTERNAL_H_
diff --git a/third_party/abseil_cpp/absl/status/internal/statusor_internal.h b/third_party/abseil_cpp/absl/status/internal/statusor_internal.h
new file mode 100644
index 000000000000..eaac2c0b14c6
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/internal/statusor_internal.h
@@ -0,0 +1,396 @@
+// Copyright 2020 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.
+#ifndef ABSL_STATUS_INTERNAL_STATUSOR_INTERNAL_H_
+#define ABSL_STATUS_INTERNAL_STATUSOR_INTERNAL_H_
+
+#include <type_traits>
+#include <utility>
+
+#include "absl/base/attributes.h"
+#include "absl/meta/type_traits.h"
+#include "absl/status/status.h"
+#include "absl/utility/utility.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+
+template <typename T>
+class ABSL_MUST_USE_RESULT StatusOr;
+
+namespace internal_statusor {
+
+// Detects whether `U` has conversion operator to `StatusOr<T>`, i.e. `operator
+// StatusOr<T>()`.
+template <typename T, typename U, typename = void>
+struct HasConversionOperatorToStatusOr : std::false_type {};
+
+template <typename T, typename U>
+void test(char (*)[sizeof(std::declval<U>().operator absl::StatusOr<T>())]);
+
+template <typename T, typename U>
+struct HasConversionOperatorToStatusOr<T, U, decltype(test<T, U>(0))>
+    : std::true_type {};
+
+// Detects whether `T` is constructible or convertible from `StatusOr<U>`.
+template <typename T, typename U>
+using IsConstructibleOrConvertibleFromStatusOr =
+    absl::disjunction<std::is_constructible<T, StatusOr<U>&>,
+                      std::is_constructible<T, const StatusOr<U>&>,
+                      std::is_constructible<T, StatusOr<U>&&>,
+                      std::is_constructible<T, const StatusOr<U>&&>,
+                      std::is_convertible<StatusOr<U>&, T>,
+                      std::is_convertible<const StatusOr<U>&, T>,
+                      std::is_convertible<StatusOr<U>&&, T>,
+                      std::is_convertible<const StatusOr<U>&&, T>>;
+
+// Detects whether `T` is constructible or convertible or assignable from
+// `StatusOr<U>`.
+template <typename T, typename U>
+using IsConstructibleOrConvertibleOrAssignableFromStatusOr =
+    absl::disjunction<IsConstructibleOrConvertibleFromStatusOr<T, U>,
+                      std::is_assignable<T&, StatusOr<U>&>,
+                      std::is_assignable<T&, const StatusOr<U>&>,
+                      std::is_assignable<T&, StatusOr<U>&&>,
+                      std::is_assignable<T&, const StatusOr<U>&&>>;
+
+// Detects whether direct initializing `StatusOr<T>` from `U` is ambiguous, i.e.
+// when `U` is `StatusOr<V>` and `T` is constructible or convertible from `V`.
+template <typename T, typename U>
+struct IsDirectInitializationAmbiguous
+    : public absl::conditional_t<
+          std::is_same<absl::remove_cv_t<absl::remove_reference_t<U>>,
+                       U>::value,
+          std::false_type,
+          IsDirectInitializationAmbiguous<
+              T, absl::remove_cv_t<absl::remove_reference_t<U>>>> {};
+
+template <typename T, typename V>
+struct IsDirectInitializationAmbiguous<T, absl::StatusOr<V>>
+    : public IsConstructibleOrConvertibleFromStatusOr<T, V> {};
+
+// Checks against the constraints of the direction initialization, i.e. when
+// `StatusOr<T>::StatusOr(U&&)` should participate in overload resolution.
+template <typename T, typename U>
+using IsDirectInitializationValid = absl::disjunction<
+    // Short circuits if T is basically U.
+    std::is_same<T, absl::remove_cv_t<absl::remove_reference_t<U>>>,
+    absl::negation<absl::disjunction<
+        std::is_same<absl::StatusOr<T>,
+                     absl::remove_cv_t<absl::remove_reference_t<U>>>,
+        std::is_same<absl::Status,
+                     absl::remove_cv_t<absl::remove_reference_t<U>>>,
+        std::is_same<absl::in_place_t,
+                     absl::remove_cv_t<absl::remove_reference_t<U>>>,
+        IsDirectInitializationAmbiguous<T, U>>>>;
+
+// This trait detects whether `StatusOr<T>::operator=(U&&)` is ambiguous, which
+// is equivalent to whether all the following conditions are met:
+// 1. `U` is `StatusOr<V>`.
+// 2. `T` is constructible and assignable from `V`.
+// 3. `T` is constructible and assignable from `U` (i.e. `StatusOr<V>`).
+// For example, the following code is considered ambiguous:
+// (`T` is `bool`, `U` is `StatusOr<bool>`, `V` is `bool`)
+//   StatusOr<bool> s1 = true;  // s1.ok() && s1.ValueOrDie() == true
+//   StatusOr<bool> s2 = false;  // s2.ok() && s2.ValueOrDie() == false
+//   s1 = s2;  // ambiguous, `s1 = s2.ValueOrDie()` or `s1 = bool(s2)`?
+template <typename T, typename U>
+struct IsForwardingAssignmentAmbiguous
+    : public absl::conditional_t<
+          std::is_same<absl::remove_cv_t<absl::remove_reference_t<U>>,
+                       U>::value,
+          std::false_type,
+          IsForwardingAssignmentAmbiguous<
+              T, absl::remove_cv_t<absl::remove_reference_t<U>>>> {};
+
+template <typename T, typename U>
+struct IsForwardingAssignmentAmbiguous<T, absl::StatusOr<U>>
+    : public IsConstructibleOrConvertibleOrAssignableFromStatusOr<T, U> {};
+
+// Checks against the constraints of the forwarding assignment, i.e. whether
+// `StatusOr<T>::operator(U&&)` should participate in overload resolution.
+template <typename T, typename U>
+using IsForwardingAssignmentValid = absl::disjunction<
+    // Short circuits if T is basically U.
+    std::is_same<T, absl::remove_cv_t<absl::remove_reference_t<U>>>,
+    absl::negation<absl::disjunction<
+        std::is_same<absl::StatusOr<T>,
+                     absl::remove_cv_t<absl::remove_reference_t<U>>>,
+        std::is_same<absl::Status,
+                     absl::remove_cv_t<absl::remove_reference_t<U>>>,
+        std::is_same<absl::in_place_t,
+                     absl::remove_cv_t<absl::remove_reference_t<U>>>,
+        IsForwardingAssignmentAmbiguous<T, U>>>>;
+
+class Helper {
+ public:
+  // Move type-agnostic error handling to the .cc.
+  static void HandleInvalidStatusCtorArg(Status*);
+  ABSL_ATTRIBUTE_NORETURN static void Crash(const absl::Status& status);
+};
+
+// Construct an instance of T in `p` through placement new, passing Args... to
+// the constructor.
+// This abstraction is here mostly for the gcc performance fix.
+template <typename T, typename... Args>
+ABSL_ATTRIBUTE_NONNULL(1) void PlacementNew(void* p, Args&&... args) {
+  new (p) T(std::forward<Args>(args)...);
+}
+
+// Helper base class to hold the data and all operations.
+// We move all this to a base class to allow mixing with the appropriate
+// TraitsBase specialization.
+template <typename T>
+class StatusOrData {
+  template <typename U>
+  friend class StatusOrData;
+
+ public:
+  StatusOrData() = delete;
+
+  StatusOrData(const StatusOrData& other) {
+    if (other.ok()) {
+      MakeValue(other.data_);
+      MakeStatus();
+    } else {
+      MakeStatus(other.status_);
+    }
+  }
+
+  StatusOrData(StatusOrData&& other) noexcept {
+    if (other.ok()) {
+      MakeValue(std::move(other.data_));
+      MakeStatus();
+    } else {
+      MakeStatus(std::move(other.status_));
+    }
+  }
+
+  template <typename U>
+  explicit StatusOrData(const StatusOrData<U>& other) {
+    if (other.ok()) {
+      MakeValue(other.data_);
+      MakeStatus();
+    } else {
+      MakeStatus(other.status_);
+    }
+  }
+
+  template <typename U>
+  explicit StatusOrData(StatusOrData<U>&& other) {
+    if (other.ok()) {
+      MakeValue(std::move(other.data_));
+      MakeStatus();
+    } else {
+      MakeStatus(std::move(other.status_));
+    }
+  }
+
+  template <typename... Args>
+  explicit StatusOrData(absl::in_place_t, Args&&... args)
+      : data_(std::forward<Args>(args)...) {
+    MakeStatus();
+  }
+
+  explicit StatusOrData(const T& value) : data_(value) {
+    MakeStatus();
+  }
+  explicit StatusOrData(T&& value) : data_(std::move(value)) {
+    MakeStatus();
+  }
+
+  template <typename U,
+            absl::enable_if_t<std::is_constructible<absl::Status, U&&>::value,
+                              int> = 0>
+  explicit StatusOrData(U&& v) : status_(std::forward<U>(v)) {
+    EnsureNotOk();
+  }
+
+  StatusOrData& operator=(const StatusOrData& other) {
+    if (this == &other) return *this;
+    if (other.ok())
+      Assign(other.data_);
+    else
+      AssignStatus(other.status_);
+    return *this;
+  }
+
+  StatusOrData& operator=(StatusOrData&& other) {
+    if (this == &other) return *this;
+    if (other.ok())
+      Assign(std::move(other.data_));
+    else
+      AssignStatus(std::move(other.status_));
+    return *this;
+  }
+
+  ~StatusOrData() {
+    if (ok()) {
+      status_.~Status();
+      data_.~T();
+    } else {
+      status_.~Status();
+    }
+  }
+
+  template <typename U>
+  void Assign(U&& value) {
+    if (ok()) {
+      data_ = std::forward<U>(value);
+    } else {
+      MakeValue(std::forward<U>(value));
+      status_ = OkStatus();
+    }
+  }
+
+  template <typename U>
+  void AssignStatus(U&& v) {
+    Clear();
+    status_ = static_cast<absl::Status>(std::forward<U>(v));
+    EnsureNotOk();
+  }
+
+  bool ok() const { return status_.ok(); }
+
+ protected:
+  // status_ will always be active after the constructor.
+  // We make it a union to be able to initialize exactly how we need without
+  // waste.
+  // Eg. in the copy constructor we use the default constructor of Status in
+  // the ok() path to avoid an extra Ref call.
+  union {
+    Status status_;
+  };
+
+  // data_ is active iff status_.ok()==true
+  struct Dummy {};
+  union {
+    // When T is const, we need some non-const object we can cast to void* for
+    // the placement new. dummy_ is that object.
+    Dummy dummy_;
+    T data_;
+  };
+
+  void Clear() {
+    if (ok()) data_.~T();
+  }
+
+  void EnsureOk() const {
+    if (ABSL_PREDICT_FALSE(!ok())) Helper::Crash(status_);
+  }
+
+  void EnsureNotOk() {
+    if (ABSL_PREDICT_FALSE(ok())) Helper::HandleInvalidStatusCtorArg(&status_);
+  }
+
+  // Construct the value (ie. data_) through placement new with the passed
+  // argument.
+  template <typename... Arg>
+  void MakeValue(Arg&&... arg) {
+    internal_statusor::PlacementNew<T>(&dummy_, std::forward<Arg>(arg)...);
+  }
+
+  // Construct the status (ie. status_) through placement new with the passed
+  // argument.
+  template <typename... Args>
+  void MakeStatus(Args&&... args) {
+    internal_statusor::PlacementNew<Status>(&status_,
+                                            std::forward<Args>(args)...);
+  }
+};
+
+// Helper base classes to allow implicitly deleted constructors and assignment
+// operators in `StatusOr`. For example, `CopyCtorBase` will explicitly delete
+// the copy constructor when T is not copy constructible and `StatusOr` will
+// inherit that behavior implicitly.
+template <typename T, bool = std::is_copy_constructible<T>::value>
+struct CopyCtorBase {
+  CopyCtorBase() = default;
+  CopyCtorBase(const CopyCtorBase&) = default;
+  CopyCtorBase(CopyCtorBase&&) = default;
+  CopyCtorBase& operator=(const CopyCtorBase&) = default;
+  CopyCtorBase& operator=(CopyCtorBase&&) = default;
+};
+
+template <typename T>
+struct CopyCtorBase<T, false> {
+  CopyCtorBase() = default;
+  CopyCtorBase(const CopyCtorBase&) = delete;
+  CopyCtorBase(CopyCtorBase&&) = default;
+  CopyCtorBase& operator=(const CopyCtorBase&) = default;
+  CopyCtorBase& operator=(CopyCtorBase&&) = default;
+};
+
+template <typename T, bool = std::is_move_constructible<T>::value>
+struct MoveCtorBase {
+  MoveCtorBase() = default;
+  MoveCtorBase(const MoveCtorBase&) = default;
+  MoveCtorBase(MoveCtorBase&&) = default;
+  MoveCtorBase& operator=(const MoveCtorBase&) = default;
+  MoveCtorBase& operator=(MoveCtorBase&&) = default;
+};
+
+template <typename T>
+struct MoveCtorBase<T, false> {
+  MoveCtorBase() = default;
+  MoveCtorBase(const MoveCtorBase&) = default;
+  MoveCtorBase(MoveCtorBase&&) = delete;
+  MoveCtorBase& operator=(const MoveCtorBase&) = default;
+  MoveCtorBase& operator=(MoveCtorBase&&) = default;
+};
+
+template <typename T, bool = std::is_copy_constructible<T>::value&&
+                          std::is_copy_assignable<T>::value>
+struct CopyAssignBase {
+  CopyAssignBase() = default;
+  CopyAssignBase(const CopyAssignBase&) = default;
+  CopyAssignBase(CopyAssignBase&&) = default;
+  CopyAssignBase& operator=(const CopyAssignBase&) = default;
+  CopyAssignBase& operator=(CopyAssignBase&&) = default;
+};
+
+template <typename T>
+struct CopyAssignBase<T, false> {
+  CopyAssignBase() = default;
+  CopyAssignBase(const CopyAssignBase&) = default;
+  CopyAssignBase(CopyAssignBase&&) = default;
+  CopyAssignBase& operator=(const CopyAssignBase&) = delete;
+  CopyAssignBase& operator=(CopyAssignBase&&) = default;
+};
+
+template <typename T, bool = std::is_move_constructible<T>::value&&
+                          std::is_move_assignable<T>::value>
+struct MoveAssignBase {
+  MoveAssignBase() = default;
+  MoveAssignBase(const MoveAssignBase&) = default;
+  MoveAssignBase(MoveAssignBase&&) = default;
+  MoveAssignBase& operator=(const MoveAssignBase&) = default;
+  MoveAssignBase& operator=(MoveAssignBase&&) = default;
+};
+
+template <typename T>
+struct MoveAssignBase<T, false> {
+  MoveAssignBase() = default;
+  MoveAssignBase(const MoveAssignBase&) = default;
+  MoveAssignBase(MoveAssignBase&&) = default;
+  MoveAssignBase& operator=(const MoveAssignBase&) = default;
+  MoveAssignBase& operator=(MoveAssignBase&&) = delete;
+};
+
+ABSL_ATTRIBUTE_NORETURN void ThrowBadStatusOrAccess(absl::Status status);
+
+}  // namespace internal_statusor
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_STATUS_INTERNAL_STATUSOR_INTERNAL_H_
diff --git a/third_party/abseil_cpp/absl/status/status.cc b/third_party/abseil_cpp/absl/status/status.cc
new file mode 100644
index 000000000000..c71de846827c
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/status.cc
@@ -0,0 +1,442 @@
+// 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.
+#include "absl/status/status.h"
+
+#include <cassert>
+
+#include "absl/base/internal/raw_logging.h"
+#include "absl/debugging/stacktrace.h"
+#include "absl/debugging/symbolize.h"
+#include "absl/status/status_payload_printer.h"
+#include "absl/strings/escaping.h"
+#include "absl/strings/str_cat.h"
+#include "absl/strings/str_format.h"
+#include "absl/strings/str_split.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+
+std::string StatusCodeToString(StatusCode code) {
+  switch (code) {
+    case StatusCode::kOk:
+      return "OK";
+    case StatusCode::kCancelled:
+      return "CANCELLED";
+    case StatusCode::kUnknown:
+      return "UNKNOWN";
+    case StatusCode::kInvalidArgument:
+      return "INVALID_ARGUMENT";
+    case StatusCode::kDeadlineExceeded:
+      return "DEADLINE_EXCEEDED";
+    case StatusCode::kNotFound:
+      return "NOT_FOUND";
+    case StatusCode::kAlreadyExists:
+      return "ALREADY_EXISTS";
+    case StatusCode::kPermissionDenied:
+      return "PERMISSION_DENIED";
+    case StatusCode::kUnauthenticated:
+      return "UNAUTHENTICATED";
+    case StatusCode::kResourceExhausted:
+      return "RESOURCE_EXHAUSTED";
+    case StatusCode::kFailedPrecondition:
+      return "FAILED_PRECONDITION";
+    case StatusCode::kAborted:
+      return "ABORTED";
+    case StatusCode::kOutOfRange:
+      return "OUT_OF_RANGE";
+    case StatusCode::kUnimplemented:
+      return "UNIMPLEMENTED";
+    case StatusCode::kInternal:
+      return "INTERNAL";
+    case StatusCode::kUnavailable:
+      return "UNAVAILABLE";
+    case StatusCode::kDataLoss:
+      return "DATA_LOSS";
+    default:
+      return "";
+  }
+}
+
+std::ostream& operator<<(std::ostream& os, StatusCode code) {
+  return os << StatusCodeToString(code);
+}
+
+namespace status_internal {
+
+static int FindPayloadIndexByUrl(const Payloads* payloads,
+                                 absl::string_view type_url) {
+  if (payloads == nullptr) return -1;
+
+  for (size_t i = 0; i < payloads->size(); ++i) {
+    if ((*payloads)[i].type_url == type_url) return i;
+  }
+
+  return -1;
+}
+
+// Convert canonical code to a value known to this binary.
+absl::StatusCode MapToLocalCode(int value) {
+  absl::StatusCode code = static_cast<absl::StatusCode>(value);
+  switch (code) {
+    case absl::StatusCode::kOk:
+    case absl::StatusCode::kCancelled:
+    case absl::StatusCode::kUnknown:
+    case absl::StatusCode::kInvalidArgument:
+    case absl::StatusCode::kDeadlineExceeded:
+    case absl::StatusCode::kNotFound:
+    case absl::StatusCode::kAlreadyExists:
+    case absl::StatusCode::kPermissionDenied:
+    case absl::StatusCode::kResourceExhausted:
+    case absl::StatusCode::kFailedPrecondition:
+    case absl::StatusCode::kAborted:
+    case absl::StatusCode::kOutOfRange:
+    case absl::StatusCode::kUnimplemented:
+    case absl::StatusCode::kInternal:
+    case absl::StatusCode::kUnavailable:
+    case absl::StatusCode::kDataLoss:
+    case absl::StatusCode::kUnauthenticated:
+      return code;
+    default:
+      return absl::StatusCode::kUnknown;
+  }
+}
+}  // namespace status_internal
+
+absl::optional<absl::Cord> Status::GetPayload(
+    absl::string_view type_url) const {
+  const auto* payloads = GetPayloads();
+  int index = status_internal::FindPayloadIndexByUrl(payloads, type_url);
+  if (index != -1) return (*payloads)[index].payload;
+
+  return absl::nullopt;
+}
+
+void Status::SetPayload(absl::string_view type_url, absl::Cord payload) {
+  if (ok()) return;
+
+  PrepareToModify();
+
+  status_internal::StatusRep* rep = RepToPointer(rep_);
+  if (!rep->payloads) {
+    rep->payloads = absl::make_unique<status_internal::Payloads>();
+  }
+
+  int index =
+      status_internal::FindPayloadIndexByUrl(rep->payloads.get(), type_url);
+  if (index != -1) {
+    (*rep->payloads)[index].payload = std::move(payload);
+    return;
+  }
+
+  rep->payloads->push_back({std::string(type_url), std::move(payload)});
+}
+
+bool Status::ErasePayload(absl::string_view type_url) {
+  int index = status_internal::FindPayloadIndexByUrl(GetPayloads(), type_url);
+  if (index != -1) {
+    PrepareToModify();
+    GetPayloads()->erase(GetPayloads()->begin() + index);
+    if (GetPayloads()->empty() && message().empty()) {
+      // Special case: If this can be represented inlined, it MUST be
+      // inlined (EqualsSlow depends on this behavior).
+      StatusCode c = static_cast<StatusCode>(raw_code());
+      Unref(rep_);
+      rep_ = CodeToInlinedRep(c);
+    }
+    return true;
+  }
+
+  return false;
+}
+
+void Status::ForEachPayload(
+    const std::function<void(absl::string_view, const absl::Cord&)>& visitor)
+    const {
+  if (auto* payloads = GetPayloads()) {
+    bool in_reverse =
+        payloads->size() > 1 && reinterpret_cast<uintptr_t>(payloads) % 13 > 6;
+
+    for (size_t index = 0; index < payloads->size(); ++index) {
+      const auto& elem =
+          (*payloads)[in_reverse ? payloads->size() - 1 - index : index];
+
+#ifdef NDEBUG
+      visitor(elem.type_url, elem.payload);
+#else
+      // In debug mode invalidate the type url to prevent users from relying on
+      // this string lifetime.
+
+      // NOLINTNEXTLINE intentional extra conversion to force temporary.
+      visitor(std::string(elem.type_url), elem.payload);
+#endif  // NDEBUG
+    }
+  }
+}
+
+const std::string* Status::EmptyString() {
+  static std::string* empty_string = new std::string();
+  return empty_string;
+}
+
+constexpr const char Status::kMovedFromString[];
+
+const std::string* Status::MovedFromString() {
+  static std::string* moved_from_string = new std::string(kMovedFromString);
+  return moved_from_string;
+}
+
+void Status::UnrefNonInlined(uintptr_t rep) {
+  status_internal::StatusRep* r = RepToPointer(rep);
+  // Fast path: if ref==1, there is no need for a RefCountDec (since
+  // this is the only reference and therefore no other thread is
+  // allowed to be mucking with r).
+  if (r->ref.load(std::memory_order_acquire) == 1 ||
+      r->ref.fetch_sub(1, std::memory_order_acq_rel) - 1 == 0) {
+    delete r;
+  }
+}
+
+uintptr_t Status::NewRep(absl::StatusCode code, absl::string_view msg,
+                         std::unique_ptr<status_internal::Payloads> payloads) {
+  status_internal::StatusRep* rep = new status_internal::StatusRep(
+      code, std::string(msg.data(), msg.size()), std::move(payloads));
+  return PointerToRep(rep);
+}
+
+Status::Status(absl::StatusCode code, absl::string_view msg)
+    : rep_(CodeToInlinedRep(code)) {
+  if (code != absl::StatusCode::kOk && !msg.empty()) {
+    rep_ = NewRep(code, msg, nullptr);
+  }
+}
+
+int Status::raw_code() const {
+  if (IsInlined(rep_)) {
+    return static_cast<int>(InlinedRepToCode(rep_));
+  }
+  status_internal::StatusRep* rep = RepToPointer(rep_);
+  return static_cast<int>(rep->code);
+}
+
+absl::StatusCode Status::code() const {
+  return status_internal::MapToLocalCode(raw_code());
+}
+
+void Status::PrepareToModify() {
+  ABSL_RAW_CHECK(!ok(), "PrepareToModify shouldn't be called on OK status.");
+  if (IsInlined(rep_)) {
+    rep_ = NewRep(static_cast<absl::StatusCode>(raw_code()),
+                  absl::string_view(), nullptr);
+    return;
+  }
+
+  uintptr_t rep_i = rep_;
+  status_internal::StatusRep* rep = RepToPointer(rep_);
+  if (rep->ref.load(std::memory_order_acquire) != 1) {
+    std::unique_ptr<status_internal::Payloads> payloads;
+    if (rep->payloads) {
+      payloads = absl::make_unique<status_internal::Payloads>(*rep->payloads);
+    }
+    rep_ = NewRep(rep->code, message(), std::move(payloads));
+    UnrefNonInlined(rep_i);
+  }
+}
+
+bool Status::EqualsSlow(const absl::Status& a, const absl::Status& b) {
+  if (IsInlined(a.rep_) != IsInlined(b.rep_)) return false;
+  if (a.message() != b.message()) return false;
+  if (a.raw_code() != b.raw_code()) return false;
+  if (a.GetPayloads() == b.GetPayloads()) return true;
+
+  const status_internal::Payloads no_payloads;
+  const status_internal::Payloads* larger_payloads =
+      a.GetPayloads() ? a.GetPayloads() : &no_payloads;
+  const status_internal::Payloads* smaller_payloads =
+      b.GetPayloads() ? b.GetPayloads() : &no_payloads;
+  if (larger_payloads->size() < smaller_payloads->size()) {
+    std::swap(larger_payloads, smaller_payloads);
+  }
+  if ((larger_payloads->size() - smaller_payloads->size()) > 1) return false;
+  // Payloads can be ordered differently, so we can't just compare payload
+  // vectors.
+  for (const auto& payload : *larger_payloads) {
+
+    bool found = false;
+    for (const auto& other_payload : *smaller_payloads) {
+      if (payload.type_url == other_payload.type_url) {
+        if (payload.payload != other_payload.payload) {
+          return false;
+        }
+        found = true;
+        break;
+      }
+    }
+    if (!found) return false;
+  }
+  return true;
+}
+
+std::string Status::ToStringSlow() const {
+  std::string text;
+  absl::StrAppend(&text, absl::StatusCodeToString(code()), ": ", message());
+  status_internal::StatusPayloadPrinter printer =
+      status_internal::GetStatusPayloadPrinter();
+  this->ForEachPayload([&](absl::string_view type_url,
+                           const absl::Cord& payload) {
+    absl::optional<std::string> result;
+    if (printer) result = printer(type_url, payload);
+    absl::StrAppend(
+        &text, " [", type_url, "='",
+        result.has_value() ? *result : absl::CHexEscape(std::string(payload)),
+        "']");
+  });
+
+  return text;
+}
+
+std::ostream& operator<<(std::ostream& os, const Status& x) {
+  os << x.ToString();
+  return os;
+}
+
+Status AbortedError(absl::string_view message) {
+  return Status(absl::StatusCode::kAborted, message);
+}
+
+Status AlreadyExistsError(absl::string_view message) {
+  return Status(absl::StatusCode::kAlreadyExists, message);
+}
+
+Status CancelledError(absl::string_view message) {
+  return Status(absl::StatusCode::kCancelled, message);
+}
+
+Status DataLossError(absl::string_view message) {
+  return Status(absl::StatusCode::kDataLoss, message);
+}
+
+Status DeadlineExceededError(absl::string_view message) {
+  return Status(absl::StatusCode::kDeadlineExceeded, message);
+}
+
+Status FailedPreconditionError(absl::string_view message) {
+  return Status(absl::StatusCode::kFailedPrecondition, message);
+}
+
+Status InternalError(absl::string_view message) {
+  return Status(absl::StatusCode::kInternal, message);
+}
+
+Status InvalidArgumentError(absl::string_view message) {
+  return Status(absl::StatusCode::kInvalidArgument, message);
+}
+
+Status NotFoundError(absl::string_view message) {
+  return Status(absl::StatusCode::kNotFound, message);
+}
+
+Status OutOfRangeError(absl::string_view message) {
+  return Status(absl::StatusCode::kOutOfRange, message);
+}
+
+Status PermissionDeniedError(absl::string_view message) {
+  return Status(absl::StatusCode::kPermissionDenied, message);
+}
+
+Status ResourceExhaustedError(absl::string_view message) {
+  return Status(absl::StatusCode::kResourceExhausted, message);
+}
+
+Status UnauthenticatedError(absl::string_view message) {
+  return Status(absl::StatusCode::kUnauthenticated, message);
+}
+
+Status UnavailableError(absl::string_view message) {
+  return Status(absl::StatusCode::kUnavailable, message);
+}
+
+Status UnimplementedError(absl::string_view message) {
+  return Status(absl::StatusCode::kUnimplemented, message);
+}
+
+Status UnknownError(absl::string_view message) {
+  return Status(absl::StatusCode::kUnknown, message);
+}
+
+bool IsAborted(const Status& status) {
+  return status.code() == absl::StatusCode::kAborted;
+}
+
+bool IsAlreadyExists(const Status& status) {
+  return status.code() == absl::StatusCode::kAlreadyExists;
+}
+
+bool IsCancelled(const Status& status) {
+  return status.code() == absl::StatusCode::kCancelled;
+}
+
+bool IsDataLoss(const Status& status) {
+  return status.code() == absl::StatusCode::kDataLoss;
+}
+
+bool IsDeadlineExceeded(const Status& status) {
+  return status.code() == absl::StatusCode::kDeadlineExceeded;
+}
+
+bool IsFailedPrecondition(const Status& status) {
+  return status.code() == absl::StatusCode::kFailedPrecondition;
+}
+
+bool IsInternal(const Status& status) {
+  return status.code() == absl::StatusCode::kInternal;
+}
+
+bool IsInvalidArgument(const Status& status) {
+  return status.code() == absl::StatusCode::kInvalidArgument;
+}
+
+bool IsNotFound(const Status& status) {
+  return status.code() == absl::StatusCode::kNotFound;
+}
+
+bool IsOutOfRange(const Status& status) {
+  return status.code() == absl::StatusCode::kOutOfRange;
+}
+
+bool IsPermissionDenied(const Status& status) {
+  return status.code() == absl::StatusCode::kPermissionDenied;
+}
+
+bool IsResourceExhausted(const Status& status) {
+  return status.code() == absl::StatusCode::kResourceExhausted;
+}
+
+bool IsUnauthenticated(const Status& status) {
+  return status.code() == absl::StatusCode::kUnauthenticated;
+}
+
+bool IsUnavailable(const Status& status) {
+  return status.code() == absl::StatusCode::kUnavailable;
+}
+
+bool IsUnimplemented(const Status& status) {
+  return status.code() == absl::StatusCode::kUnimplemented;
+}
+
+bool IsUnknown(const Status& status) {
+  return status.code() == absl::StatusCode::kUnknown;
+}
+
+ABSL_NAMESPACE_END
+}  // namespace absl
diff --git a/third_party/abseil_cpp/absl/status/status.h b/third_party/abseil_cpp/absl/status/status.h
new file mode 100644
index 000000000000..c4d6fce09050
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/status.h
@@ -0,0 +1,817 @@
+// 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.
+//
+// -----------------------------------------------------------------------------
+// File: status.h
+// -----------------------------------------------------------------------------
+//
+// This header file defines the Abseil `status` library, consisting of:
+//
+//   * An `absl::Status` class for holding error handling information
+//   * A set of canonical `absl::StatusCode` error codes, and associated
+//     utilities for generating and propagating status codes.
+//   * A set of helper functions for creating status codes and checking their
+//     values
+//
+// Within Google, `absl::Status` is the primary mechanism for gracefully
+// handling errors across API boundaries (and in particular across RPC
+// boundaries). Some of these errors may be recoverable, but others may not.
+// Most functions that can produce a recoverable error should be designed to
+// return an `absl::Status` (or `absl::StatusOr`).
+//
+// Example:
+//
+// absl::Status myFunction(absl::string_view fname, ...) {
+//   ...
+//   // encounter error
+//   if (error condition) {
+//     return absl::InvalidArgumentError("bad mode");
+//   }
+//   // else, return OK
+//   return absl::OkStatus();
+// }
+//
+// An `absl::Status` is designed to either return "OK" or one of a number of
+// different error codes, corresponding to typical error conditions.
+// In almost all cases, when using `absl::Status` you should use the canonical
+// error codes (of type `absl::StatusCode`) enumerated in this header file.
+// These canonical codes are understood across the codebase and will be
+// accepted across all API and RPC boundaries.
+#ifndef ABSL_STATUS_STATUS_H_
+#define ABSL_STATUS_STATUS_H_
+
+#include <iostream>
+#include <string>
+
+#include "absl/container/inlined_vector.h"
+#include "absl/status/internal/status_internal.h"
+#include "absl/strings/cord.h"
+#include "absl/types/optional.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+
+// absl::StatusCode
+//
+// An `absl::StatusCode` is an enumerated type indicating either no error ("OK")
+// or an error condition. In most cases, an `absl::Status` indicates a
+// recoverable error, and the purpose of signalling an error is to indicate what
+// action to take in response to that error. These error codes map to the proto
+// RPC error codes indicated in https://cloud.google.com/apis/design/errors.
+//
+// The errors listed below are the canonical errors associated with
+// `absl::Status` and are used throughout the codebase. As a result, these
+// error codes are somewhat generic.
+//
+// In general, try to return the most specific error that applies if more than
+// one error may pertain. For example, prefer `kOutOfRange` over
+// `kFailedPrecondition` if both codes apply. Similarly prefer `kNotFound` or
+// `kAlreadyExists` over `kFailedPrecondition`.
+//
+// Because these errors may travel RPC boundaries, these codes are tied to the
+// `google.rpc.Code` definitions within
+// https://github.com/googleapis/googleapis/blob/master/google/rpc/code.proto
+// The string value of these RPC codes is denoted within each enum below.
+//
+// If your error handling code requires more context, you can attach payloads
+// to your status. See `absl::Status::SetPayload()` and
+// `absl::Status::GetPayload()` below.
+enum class StatusCode : int {
+  // StatusCode::kOk
+  //
+  // kOK (gRPC code "OK") does not indicate an error; this value is returned on
+  // success. It is typical to check for this value before proceeding on any
+  // given call across an API or RPC boundary. To check this value, use the
+  // `absl::Status::ok()` member function rather than inspecting the raw code.
+  kOk = 0,
+
+  // StatusCode::kCancelled
+  //
+  // kCancelled (gRPC code "CANCELLED") indicates the operation was cancelled,
+  // typically by the caller.
+  kCancelled = 1,
+
+  // StatusCode::kUnknown
+  //
+  // kUnknown (gRPC code "UNKNOWN") indicates an unknown error occurred. In
+  // general, more specific errors should be raised, if possible. Errors raised
+  // by APIs that do not return enough error information may be converted to
+  // this error.
+  kUnknown = 2,
+
+  // StatusCode::kInvalidArgument
+  //
+  // kInvalidArgument (gRPC code "INVALID_ARGUMENT") indicates the caller
+  // specified an invalid argument, such a malformed filename. Note that such
+  // errors should be narrowly limited to indicate to the invalid nature of the
+  // arguments themselves. Errors with validly formed arguments that may cause
+  // errors with the state of the receiving system should be denoted with
+  // `kFailedPrecondition` instead.
+  kInvalidArgument = 3,
+
+  // StatusCode::kDeadlineExceeded
+  //
+  // kDeadlineExceeded (gRPC code "DEADLINE_EXCEEDED") indicates a deadline
+  // expired before the operation could complete. For operations that may change
+  // state within a system, this error may be returned even if the operation has
+  // completed successfully. For example, a successful response from a server
+  // could have been delayed long enough for the deadline to expire.
+  kDeadlineExceeded = 4,
+
+  // StatusCode::kNotFound
+  //
+  // kNotFound (gRPC code "NOT_FOUND") indicates some requested entity (such as
+  // a file or directory) was not found.
+  //
+  // `kNotFound` is useful if a request should be denied for an entire class of
+  // users, such as during a gradual feature rollout or undocumented allow list.
+  // If, instead, a request should be denied for specific sets of users, such as
+  // through user-based access control, use `kPermissionDenied` instead.
+  kNotFound = 5,
+
+  // StatusCode::kAlreadyExists
+  //
+  // kAlreadyExists (gRPC code "ALREADY_EXISTS") indicates the entity that a
+  // caller attempted to create (such as file or directory) is already present.
+  kAlreadyExists = 6,
+
+  // StatusCode::kPermissionDenied
+  //
+  // kPermissionDenied (gRPC code "PERMISSION_DENIED") indicates that the caller
+  // does not have permission to execute the specified operation. Note that this
+  // error is different than an error due to an *un*authenticated user. This
+  // error code does not imply the request is valid or the requested entity
+  // exists or satisfies any other pre-conditions.
+  //
+  // `kPermissionDenied` must not be used for rejections caused by exhausting
+  // some resource. Instead, use `kResourceExhausted` for those errors.
+  // `kPermissionDenied` must not be used if the caller cannot be identified.
+  // Instead, use `kUnauthenticated` for those errors.
+  kPermissionDenied = 7,
+
+  // StatusCode::kResourceExhausted
+  //
+  // kResourceExhausted (gRPC code "RESOURCE_EXHAUSTED") indicates some resource
+  // has been exhausted, perhaps a per-user quota, or perhaps the entire file
+  // system is out of space.
+  kResourceExhausted = 8,
+
+  // StatusCode::kFailedPrecondition
+  //
+  // kFailedPrecondition (gRPC code "FAILED_PRECONDITION") indicates that the
+  // operation was rejected because the system is not in a state required for
+  // the operation's execution. For example, a directory to be deleted may be
+  // non-empty, an "rmdir" operation is applied to a non-directory, etc.
+  //
+  // Some guidelines that may help a service implementer in deciding between
+  // `kFailedPrecondition`, `kAborted`, and `kUnavailable`:
+  //
+  //  (a) Use `kUnavailable` if the client can retry just the failing call.
+  //  (b) Use `kAborted` if the client should retry at a higher transaction
+  //      level (such as when a client-specified test-and-set fails, indicating
+  //      the client should restart a read-modify-write sequence).
+  //  (c) Use `kFailedPrecondition` if the client should not retry until
+  //      the system state has been explicitly fixed. For example, if an "rmdir"
+  //      fails because the directory is non-empty, `kFailedPrecondition`
+  //      should be returned since the client should not retry unless
+  //      the files are deleted from the directory.
+  kFailedPrecondition = 9,
+
+  // StatusCode::kAborted
+  //
+  // kAborted (gRPC code "ABORTED") indicates the operation was aborted,
+  // typically due to a concurrency issue such as a sequencer check failure or a
+  // failed transaction.
+  //
+  // See the guidelines above for deciding between `kFailedPrecondition`,
+  // `kAborted`, and `kUnavailable`.
+  kAborted = 10,
+
+  // StatusCode::kOutOfRange
+  //
+  // kOutOfRange (gRPC code "OUT_OF_RANGE") indicates the operation was
+  // attempted past the valid range, such as seeking or reading past an
+  // end-of-file.
+  //
+  // Unlike `kInvalidArgument`, this error indicates a problem that may
+  // be fixed if the system state changes. For example, a 32-bit file
+  // system will generate `kInvalidArgument` if asked to read at an
+  // offset that is not in the range [0,2^32-1], but it will generate
+  // `kOutOfRange` if asked to read from an offset past the current
+  // file size.
+  //
+  // There is a fair bit of overlap between `kFailedPrecondition` and
+  // `kOutOfRange`.  We recommend using `kOutOfRange` (the more specific
+  // error) when it applies so that callers who are iterating through
+  // a space can easily look for an `kOutOfRange` error to detect when
+  // they are done.
+  kOutOfRange = 11,
+
+  // StatusCode::kUnimplemented
+  //
+  // kUnimplemented (gRPC code "UNIMPLEMENTED") indicates the operation is not
+  // implemented or supported in this service. In this case, the operation
+  // should not be re-attempted.
+  kUnimplemented = 12,
+
+  // StatusCode::kInternal
+  //
+  // kInternal (gRPC code "INTERNAL") indicates an internal error has occurred
+  // and some invariants expected by the underlying system have not been
+  // satisfied. This error code is reserved for serious errors.
+  kInternal = 13,
+
+  // StatusCode::kUnavailable
+  //
+  // kUnavailable (gRPC code "UNAVAILABLE") indicates the service is currently
+  // unavailable and that this is most likely a transient condition. An error
+  // such as this can be corrected by retrying with a backoff scheme. Note that
+  // it is not always safe to retry non-idempotent operations.
+  //
+  // See the guidelines above for deciding between `kFailedPrecondition`,
+  // `kAborted`, and `kUnavailable`.
+  kUnavailable = 14,
+
+  // StatusCode::kDataLoss
+  //
+  // kDataLoss (gRPC code "DATA_LOSS") indicates that unrecoverable data loss or
+  // corruption has occurred. As this error is serious, proper alerting should
+  // be attached to errors such as this.
+  kDataLoss = 15,
+
+  // StatusCode::kUnauthenticated
+  //
+  // kUnauthenticated (gRPC code "UNAUTHENTICATED") indicates that the request
+  // does not have valid authentication credentials for the operation. Correct
+  // the authentication and try again.
+  kUnauthenticated = 16,
+
+  // StatusCode::DoNotUseReservedForFutureExpansionUseDefaultInSwitchInstead_
+  //
+  // NOTE: this error code entry should not be used and you should not rely on
+  // its value, which may change.
+  //
+  // The purpose of this enumerated value is to force people who handle status
+  // codes with `switch()` statements to *not* simply enumerate all possible
+  // values, but instead provide a "default:" case. Providing such a default
+  // case ensures that code will compile when new codes are added.
+  kDoNotUseReservedForFutureExpansionUseDefaultInSwitchInstead_ = 20
+};
+
+// StatusCodeToString()
+//
+// Returns the name for the status code, or "" if it is an unknown value.
+std::string StatusCodeToString(StatusCode code);
+
+// operator<<
+//
+// Streams StatusCodeToString(code) to `os`.
+std::ostream& operator<<(std::ostream& os, StatusCode code);
+
+// absl::Status
+//
+// The `absl::Status` class is generally used to gracefully handle errors
+// across API boundaries (and in particular across RPC boundaries). Some of
+// these errors may be recoverable, but others may not. Most
+// functions which can produce a recoverable error should be designed to return
+// either an `absl::Status` (or the similar `absl::StatusOr<T>`, which holds
+// either an object of type `T` or an error).
+//
+// API developers should construct their functions to return `absl::OkStatus()`
+// upon success, or an `absl::StatusCode` upon another type of error (e.g
+// an `absl::StatusCode::kInvalidArgument` error). The API provides convenience
+// functions to constuct each status code.
+//
+// Example:
+//
+// absl::Status myFunction(absl::string_view fname, ...) {
+//   ...
+//   // encounter error
+//   if (error condition) {
+//     // Construct an absl::StatusCode::kInvalidArgument error
+//     return absl::InvalidArgumentError("bad mode");
+//   }
+//   // else, return OK
+//   return absl::OkStatus();
+// }
+//
+// Users handling status error codes should prefer checking for an OK status
+// using the `ok()` member function. Handling multiple error codes may justify
+// use of switch statement, but only check for error codes you know how to
+// handle; do not try to exhaustively match against all canonical error codes.
+// Errors that cannot be handled should be logged and/or propagated for higher
+// levels to deal with. If you do use a switch statement, make sure that you
+// also provide a `default:` switch case, so that code does not break as other
+// canonical codes are added to the API.
+//
+// Example:
+//
+//   absl::Status result = DoSomething();
+//   if (!result.ok()) {
+//     LOG(ERROR) << result;
+//   }
+//
+//   // Provide a default if switching on multiple error codes
+//   switch (result.code()) {
+//     // The user hasn't authenticated. Ask them to reauth
+//     case absl::StatusCode::kUnauthenticated:
+//       DoReAuth();
+//       break;
+//     // The user does not have permission. Log an error.
+//     case absl::StatusCode::kPermissionDenied:
+//       LOG(ERROR) << result;
+//       break;
+//     // Propagate the error otherwise.
+//     default:
+//       return true;
+//   }
+//
+// An `absl::Status` can optionally include a payload with more information
+// about the error. Typically, this payload serves one of several purposes:
+//
+//   * It may provide more fine-grained semantic information about the error to
+//     facilitate actionable remedies.
+//   * It may provide human-readable contexual information that is more
+//     appropriate to display to an end user.
+//
+// Example:
+//
+//   absl::Status result = DoSomething();
+//   // Inform user to retry after 30 seconds
+//   // See more error details in googleapis/google/rpc/error_details.proto
+//   if (absl::IsResourceExhausted(result)) {
+//     google::rpc::RetryInfo info;
+//     info.retry_delay().seconds() = 30;
+//     // Payloads require a unique key (a URL to ensure no collisions with
+//     // other payloads), and an `absl::Cord` to hold the encoded data.
+//     absl::string_view url = "type.googleapis.com/google.rpc.RetryInfo";
+//     result.SetPayload(url, info.SerializeAsCord());
+//     return result;
+//   }
+//
+class ABSL_MUST_USE_RESULT Status final {
+ public:
+  // Constructors
+
+  // This default constructor creates an OK status with no message or payload.
+  // Avoid this constructor and prefer explicit construction of an OK status
+  // with `absl::OkStatus()`.
+  Status();
+
+  // Creates a status in the canonical error space with the specified
+  // `absl::StatusCode` and error message.  If `code == absl::StatusCode::kOk`,
+  // `msg` is ignored and an object identical to an OK status is constructed.
+  //
+  // The `msg` string must be in UTF-8. The implementation may complain (e.g.,
+  // by printing a warning) if it is not.
+  Status(absl::StatusCode code, absl::string_view msg);
+
+  Status(const Status&);
+  Status& operator=(const Status& x);
+
+  // Move operators
+
+  // The moved-from state is valid but unspecified.
+  Status(Status&&) noexcept;
+  Status& operator=(Status&&);
+
+  ~Status();
+
+  // Status::Update()
+  //
+  // Updates the existing status with `new_status` provided that `this->ok()`.
+  // If the existing status already contains a non-OK error, this update has no
+  // effect and preserves the current data. Note that this behavior may change
+  // in the future to augment a current non-ok status with additional
+  // information about `new_status`.
+  //
+  // `Update()` provides a convenient way of keeping track of the first error
+  // encountered.
+  //
+  // Example:
+  //   // Instead of "if (overall_status.ok()) overall_status = new_status"
+  //   overall_status.Update(new_status);
+  //
+  void Update(const Status& new_status);
+  void Update(Status&& new_status);
+
+  // Status::ok()
+  //
+  // Returns `true` if `this->ok()`. Prefer checking for an OK status using this
+  // member function.
+  ABSL_MUST_USE_RESULT bool ok() const;
+
+  // Status::code()
+  //
+  // Returns the canonical error code of type `absl::StatusCode` of this status.
+  absl::StatusCode code() const;
+
+  // Status::raw_code()
+  //
+  // Returns a raw (canonical) error code corresponding to the enum value of
+  // `google.rpc.Code` definitions within
+  // https://github.com/googleapis/googleapis/blob/master/google/rpc/code.proto.
+  // These values could be out of the range of canonical `absl::StatusCode`
+  // enum values.
+  //
+  // NOTE: This function should only be called when converting to an associated
+  // wire format. Use `Status::code()` for error handling.
+  int raw_code() const;
+
+  // Status::message()
+  //
+  // Returns the error message associated with this error code, if available.
+  // Note that this message rarely describes the error code.  It is not unusual
+  // for the error message to be the empty string. As a result, prefer
+  // `Status::ToString()` for debug logging.
+  absl::string_view message() const;
+
+  friend bool operator==(const Status&, const Status&);
+  friend bool operator!=(const Status&, const Status&);
+
+  // Status::ToString()
+  //
+  // Returns a combination of the error code name, the message and any
+  // associated payload messages. This string is designed simply to be human
+  // readable and its exact format should not be load bearing. Do not depend on
+  // the exact format of the result of `ToString()` which is subject to change.
+  //
+  // The printed code name and the message are generally substrings of the
+  // result, and the payloads to be printed use the status payload printer
+  // mechanism (which is internal).
+  std::string ToString() const;
+
+  // Status::IgnoreError()
+  //
+  // Ignores any errors. This method does nothing except potentially suppress
+  // complaints from any tools that are checking that errors are not dropped on
+  // the floor.
+  void IgnoreError() const;
+
+  // swap()
+  //
+  // Swap the contents of one status with another.
+  friend void swap(Status& a, Status& b);
+
+  //----------------------------------------------------------------------------
+  // Payload Management APIs
+  //----------------------------------------------------------------------------
+
+  // A payload may be attached to a status to provide additional context to an
+  // error that may not be satisifed by an existing `absl::StatusCode`.
+  // Typically, this payload serves one of several purposes:
+  //
+  //   * It may provide more fine-grained semantic information about the error
+  //     to facilitate actionable remedies.
+  //   * It may provide human-readable contexual information that is more
+  //     appropriate to display to an end user.
+  //
+  // A payload consists of a [key,value] pair, where the key is a string
+  // referring to a unique "type URL" and the value is an object of type
+  // `absl::Cord` to hold the contextual data.
+  //
+  // The "type URL" should be unique and follow the format of a URL
+  // (https://en.wikipedia.org/wiki/URL) and, ideally, provide some
+  // documentation or schema on how to interpret its associated data. For
+  // example, the default type URL for a protobuf message type is
+  // "type.googleapis.com/packagename.messagename". Other custom wire formats
+  // should define the format of type URL in a similar practice so as to
+  // minimize the chance of conflict between type URLs.
+  // Users should ensure that the type URL can be mapped to a concrete
+  // C++ type if they want to deserialize the payload and read it effectively.
+  //
+  // To attach a payload to a status object, call `Status::SetPayload()`,
+  // passing it the type URL and an `absl::Cord` of associated data. Similarly,
+  // to extract the payload from a status, call `Status::GetPayload()`. You
+  // may attach multiple payloads (with differing type URLs) to any given
+  // status object, provided that the status is currently exhibiting an error
+  // code (i.e. is not OK).
+
+  // Status::GetPayload()
+  //
+  // Gets the payload of a status given its unique `type_url` key, if present.
+  absl::optional<absl::Cord> GetPayload(absl::string_view type_url) const;
+
+  // Status::SetPayload()
+  //
+  // Sets the payload for a non-ok status using a `type_url` key, overwriting
+  // any existing payload for that `type_url`.
+  //
+  // NOTE: This function does nothing if the Status is ok.
+  void SetPayload(absl::string_view type_url, absl::Cord payload);
+
+  // Status::ErasePayload()
+  //
+  // Erases the payload corresponding to the `type_url` key.  Returns `true` if
+  // the payload was present.
+  bool ErasePayload(absl::string_view type_url);
+
+  // Status::ForEachPayload()
+  //
+  // Iterates over the stored payloads and calls the
+  // `visitor(type_key, payload)` callable for each one.
+  //
+  // NOTE: The order of calls to `visitor()` is not specified and may change at
+  // any time.
+  //
+  // NOTE: Any mutation on the same 'absl::Status' object during visitation is
+  // forbidden and could result in undefined behavior.
+  void ForEachPayload(
+      const std::function<void(absl::string_view, const absl::Cord&)>& visitor)
+      const;
+
+ private:
+  friend Status CancelledError();
+
+  // Creates a status in the canonical error space with the specified
+  // code, and an empty error message.
+  explicit Status(absl::StatusCode code);
+
+  static void UnrefNonInlined(uintptr_t rep);
+  static void Ref(uintptr_t rep);
+  static void Unref(uintptr_t rep);
+
+  // REQUIRES: !ok()
+  // Ensures rep_ is not shared with any other Status.
+  void PrepareToModify();
+
+  const status_internal::Payloads* GetPayloads() const;
+  status_internal::Payloads* GetPayloads();
+
+  // Takes ownership of payload.
+  static uintptr_t NewRep(absl::StatusCode code, absl::string_view msg,
+                          std::unique_ptr<status_internal::Payloads> payload);
+  static bool EqualsSlow(const absl::Status& a, const absl::Status& b);
+
+  // MSVC 14.0 limitation requires the const.
+  static constexpr const char kMovedFromString[] =
+      "Status accessed after move.";
+
+  static const std::string* EmptyString();
+  static const std::string* MovedFromString();
+
+  // Returns whether rep contains an inlined representation.
+  // See rep_ for details.
+  static bool IsInlined(uintptr_t rep);
+
+  // Indicates whether this Status was the rhs of a move operation. See rep_
+  // for details.
+  static bool IsMovedFrom(uintptr_t rep);
+  static uintptr_t MovedFromRep();
+
+  // Convert between error::Code and the inlined uintptr_t representation used
+  // by rep_. See rep_ for details.
+  static uintptr_t CodeToInlinedRep(absl::StatusCode code);
+  static absl::StatusCode InlinedRepToCode(uintptr_t rep);
+
+  // Converts between StatusRep* and the external uintptr_t representation used
+  // by rep_. See rep_ for details.
+  static uintptr_t PointerToRep(status_internal::StatusRep* r);
+  static status_internal::StatusRep* RepToPointer(uintptr_t r);
+
+  // Returns string for non-ok Status.
+  std::string ToStringSlow() const;
+
+  // Status supports two different representations.
+  //  - When the low bit is off it is an inlined representation.
+  //    It uses the canonical error space, no message or payload.
+  //    The error code is (rep_ >> 2).
+  //    The (rep_ & 2) bit is the "moved from" indicator, used in IsMovedFrom().
+  //  - When the low bit is on it is an external representation.
+  //    In this case all the data comes from a heap allocated Rep object.
+  //    (rep_ - 1) is a status_internal::StatusRep* pointer to that structure.
+  uintptr_t rep_;
+};
+
+// OkStatus()
+//
+// Returns an OK status, equivalent to a default constructed instance. Prefer
+// usage of `absl::OkStatus()` when constructing such an OK status.
+Status OkStatus();
+
+// operator<<()
+//
+// Prints a human-readable representation of `x` to `os`.
+std::ostream& operator<<(std::ostream& os, const Status& x);
+
+// IsAborted()
+// IsAlreadyExists()
+// IsCancelled()
+// IsDataLoss()
+// IsDeadlineExceeded()
+// IsFailedPrecondition()
+// IsInternal()
+// IsInvalidArgument()
+// IsNotFound()
+// IsOutOfRange()
+// IsPermissionDenied()
+// IsResourceExhausted()
+// IsUnauthenticated()
+// IsUnavailable()
+// IsUnimplemented()
+// IsUnknown()
+//
+// These convenience functions return `true` if a given status matches the
+// `absl::StatusCode` error code of its associated function.
+ABSL_MUST_USE_RESULT bool IsAborted(const Status& status);
+ABSL_MUST_USE_RESULT bool IsAlreadyExists(const Status& status);
+ABSL_MUST_USE_RESULT bool IsCancelled(const Status& status);
+ABSL_MUST_USE_RESULT bool IsDataLoss(const Status& status);
+ABSL_MUST_USE_RESULT bool IsDeadlineExceeded(const Status& status);
+ABSL_MUST_USE_RESULT bool IsFailedPrecondition(const Status& status);
+ABSL_MUST_USE_RESULT bool IsInternal(const Status& status);
+ABSL_MUST_USE_RESULT bool IsInvalidArgument(const Status& status);
+ABSL_MUST_USE_RESULT bool IsNotFound(const Status& status);
+ABSL_MUST_USE_RESULT bool IsOutOfRange(const Status& status);
+ABSL_MUST_USE_RESULT bool IsPermissionDenied(const Status& status);
+ABSL_MUST_USE_RESULT bool IsResourceExhausted(const Status& status);
+ABSL_MUST_USE_RESULT bool IsUnauthenticated(const Status& status);
+ABSL_MUST_USE_RESULT bool IsUnavailable(const Status& status);
+ABSL_MUST_USE_RESULT bool IsUnimplemented(const Status& status);
+ABSL_MUST_USE_RESULT bool IsUnknown(const Status& status);
+
+// AbortedError()
+// AlreadyExistsError()
+// CancelledError()
+// DataLossError()
+// DeadlineExceededError()
+// FailedPreconditionError()
+// InternalError()
+// InvalidArgumentError()
+// NotFoundError()
+// OutOfRangeError()
+// PermissionDeniedError()
+// ResourceExhaustedError()
+// UnauthenticatedError()
+// UnavailableError()
+// UnimplementedError()
+// UnknownError()
+//
+// These convenience functions create an `absl::Status` object with an error
+// code as indicated by the associated function name, using the error message
+// passed in `message`.
+Status AbortedError(absl::string_view message);
+Status AlreadyExistsError(absl::string_view message);
+Status CancelledError(absl::string_view message);
+Status DataLossError(absl::string_view message);
+Status DeadlineExceededError(absl::string_view message);
+Status FailedPreconditionError(absl::string_view message);
+Status InternalError(absl::string_view message);
+Status InvalidArgumentError(absl::string_view message);
+Status NotFoundError(absl::string_view message);
+Status OutOfRangeError(absl::string_view message);
+Status PermissionDeniedError(absl::string_view message);
+Status ResourceExhaustedError(absl::string_view message);
+Status UnauthenticatedError(absl::string_view message);
+Status UnavailableError(absl::string_view message);
+Status UnimplementedError(absl::string_view message);
+Status UnknownError(absl::string_view message);
+
+//------------------------------------------------------------------------------
+// Implementation details follow
+//------------------------------------------------------------------------------
+
+inline Status::Status() : rep_(CodeToInlinedRep(absl::StatusCode::kOk)) {}
+
+inline Status::Status(absl::StatusCode code) : rep_(CodeToInlinedRep(code)) {}
+
+inline Status::Status(const Status& x) : rep_(x.rep_) { Ref(rep_); }
+
+inline Status& Status::operator=(const Status& x) {
+  uintptr_t old_rep = rep_;
+  if (x.rep_ != old_rep) {
+    Ref(x.rep_);
+    rep_ = x.rep_;
+    Unref(old_rep);
+  }
+  return *this;
+}
+
+inline Status::Status(Status&& x) noexcept : rep_(x.rep_) {
+  x.rep_ = MovedFromRep();
+}
+
+inline Status& Status::operator=(Status&& x) {
+  uintptr_t old_rep = rep_;
+  rep_ = x.rep_;
+  x.rep_ = MovedFromRep();
+  Unref(old_rep);
+  return *this;
+}
+
+inline void Status::Update(const Status& new_status) {
+  if (ok()) {
+    *this = new_status;
+  }
+}
+
+inline void Status::Update(Status&& new_status) {
+  if (ok()) {
+    *this = std::move(new_status);
+  }
+}
+
+inline Status::~Status() { Unref(rep_); }
+
+inline bool Status::ok() const {
+  return rep_ == CodeToInlinedRep(absl::StatusCode::kOk);
+}
+
+inline absl::string_view Status::message() const {
+  return !IsInlined(rep_)
+             ? RepToPointer(rep_)->message
+             : (IsMovedFrom(rep_) ? absl::string_view(kMovedFromString)
+                                  : absl::string_view());
+}
+
+inline bool operator==(const Status& lhs, const Status& rhs) {
+  return lhs.rep_ == rhs.rep_ || Status::EqualsSlow(lhs, rhs);
+}
+
+inline bool operator!=(const Status& lhs, const Status& rhs) {
+  return !(lhs == rhs);
+}
+
+inline std::string Status::ToString() const {
+  return ok() ? "OK" : ToStringSlow();
+}
+
+inline void Status::IgnoreError() const {
+  // no-op
+}
+
+inline void swap(absl::Status& a, absl::Status& b) {
+  using std::swap;
+  swap(a.rep_, b.rep_);
+}
+
+inline const status_internal::Payloads* Status::GetPayloads() const {
+  return IsInlined(rep_) ? nullptr : RepToPointer(rep_)->payloads.get();
+}
+
+inline status_internal::Payloads* Status::GetPayloads() {
+  return IsInlined(rep_) ? nullptr : RepToPointer(rep_)->payloads.get();
+}
+
+inline bool Status::IsInlined(uintptr_t rep) { return (rep & 1) == 0; }
+
+inline bool Status::IsMovedFrom(uintptr_t rep) {
+  return IsInlined(rep) && (rep & 2) != 0;
+}
+
+inline uintptr_t Status::MovedFromRep() {
+  return CodeToInlinedRep(absl::StatusCode::kInternal) | 2;
+}
+
+inline uintptr_t Status::CodeToInlinedRep(absl::StatusCode code) {
+  return static_cast<uintptr_t>(code) << 2;
+}
+
+inline absl::StatusCode Status::InlinedRepToCode(uintptr_t rep) {
+  assert(IsInlined(rep));
+  return static_cast<absl::StatusCode>(rep >> 2);
+}
+
+inline status_internal::StatusRep* Status::RepToPointer(uintptr_t rep) {
+  assert(!IsInlined(rep));
+  return reinterpret_cast<status_internal::StatusRep*>(rep - 1);
+}
+
+inline uintptr_t Status::PointerToRep(status_internal::StatusRep* rep) {
+  return reinterpret_cast<uintptr_t>(rep) + 1;
+}
+
+inline void Status::Ref(uintptr_t rep) {
+  if (!IsInlined(rep)) {
+    RepToPointer(rep)->ref.fetch_add(1, std::memory_order_relaxed);
+  }
+}
+
+inline void Status::Unref(uintptr_t rep) {
+  if (!IsInlined(rep)) {
+    UnrefNonInlined(rep);
+  }
+}
+
+inline Status OkStatus() { return Status(); }
+
+// Creates a `Status` object with the `absl::StatusCode::kCancelled` error code
+// and an empty message. It is provided only for efficiency, given that
+// message-less kCancelled errors are common in the infrastructure.
+inline Status CancelledError() { return Status(absl::StatusCode::kCancelled); }
+
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_STATUS_STATUS_H_
diff --git a/third_party/abseil_cpp/absl/status/status_payload_printer.cc b/third_party/abseil_cpp/absl/status/status_payload_printer.cc
new file mode 100644
index 000000000000..a47aea11c2d3
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/status_payload_printer.cc
@@ -0,0 +1,38 @@
+// 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.
+#include "absl/status/status_payload_printer.h"
+
+#include <atomic>
+
+#include "absl/base/attributes.h"
+#include "absl/base/internal/atomic_hook.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace status_internal {
+
+ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES
+static absl::base_internal::AtomicHook<StatusPayloadPrinter> storage;
+
+void SetStatusPayloadPrinter(StatusPayloadPrinter printer) {
+  storage.Store(printer);
+}
+
+StatusPayloadPrinter GetStatusPayloadPrinter() {
+  return storage.Load();
+}
+
+}  // namespace status_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
diff --git a/third_party/abseil_cpp/absl/status/status_payload_printer.h b/third_party/abseil_cpp/absl/status/status_payload_printer.h
new file mode 100644
index 000000000000..5e0937f67da8
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/status_payload_printer.h
@@ -0,0 +1,51 @@
+// 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.
+#ifndef ABSL_STATUS_STATUS_PAYLOAD_PRINTER_H_
+#define ABSL_STATUS_STATUS_PAYLOAD_PRINTER_H_
+
+#include <string>
+
+#include "absl/strings/cord.h"
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace status_internal {
+
+// By default, `Status::ToString` and `operator<<(Status)` print a payload by
+// dumping the type URL and the raw bytes. To help debugging, we provide an
+// extension point, which is a global printer function that can be set by users
+// to specify how to print payloads. The function takes the type URL and the
+// payload as input, and should return a valid human-readable string on success
+// or `absl::nullopt` on failure (in which case it falls back to the default
+// approach of printing the raw bytes).
+// NOTE: This is an internal API and the design is subject to change in the
+// future in a non-backward-compatible way. Since it's only meant for debugging
+// purpose, you should not rely on it in any critical logic.
+using StatusPayloadPrinter = absl::optional<std::string> (*)(absl::string_view,
+                                                             const absl::Cord&);
+
+// Sets the global payload printer. Only one printer should be set per process.
+// If multiple printers are set, it's undefined which one will be used.
+void SetStatusPayloadPrinter(StatusPayloadPrinter);
+
+// Returns the global payload printer if previously set, otherwise `nullptr`.
+StatusPayloadPrinter GetStatusPayloadPrinter();
+
+}  // namespace status_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_STATUS_STATUS_PAYLOAD_PRINTER_H_
diff --git a/third_party/abseil_cpp/absl/status/status_test.cc b/third_party/abseil_cpp/absl/status/status_test.cc
new file mode 100644
index 000000000000..ca9488ad228c
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/status_test.cc
@@ -0,0 +1,458 @@
+// 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.
+
+#include "absl/status/status.h"
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/strings/str_cat.h"
+
+namespace {
+
+using ::testing::Eq;
+using ::testing::HasSubstr;
+using ::testing::Optional;
+using ::testing::UnorderedElementsAreArray;
+
+TEST(StatusCode, InsertionOperator) {
+  const absl::StatusCode code = absl::StatusCode::kUnknown;
+  std::ostringstream oss;
+  oss << code;
+  EXPECT_EQ(oss.str(), absl::StatusCodeToString(code));
+}
+
+// This structure holds the details for testing a single error code,
+// its creator, and its classifier.
+struct ErrorTest {
+  absl::StatusCode code;
+  using Creator = absl::Status (*)(absl::string_view);
+  using Classifier = bool (*)(const absl::Status&);
+  Creator creator;
+  Classifier classifier;
+};
+
+constexpr ErrorTest kErrorTests[]{
+    {absl::StatusCode::kCancelled, absl::CancelledError, absl::IsCancelled},
+    {absl::StatusCode::kUnknown, absl::UnknownError, absl::IsUnknown},
+    {absl::StatusCode::kInvalidArgument, absl::InvalidArgumentError,
+     absl::IsInvalidArgument},
+    {absl::StatusCode::kDeadlineExceeded, absl::DeadlineExceededError,
+     absl::IsDeadlineExceeded},
+    {absl::StatusCode::kNotFound, absl::NotFoundError, absl::IsNotFound},
+    {absl::StatusCode::kAlreadyExists, absl::AlreadyExistsError,
+     absl::IsAlreadyExists},
+    {absl::StatusCode::kPermissionDenied, absl::PermissionDeniedError,
+     absl::IsPermissionDenied},
+    {absl::StatusCode::kResourceExhausted, absl::ResourceExhaustedError,
+     absl::IsResourceExhausted},
+    {absl::StatusCode::kFailedPrecondition, absl::FailedPreconditionError,
+     absl::IsFailedPrecondition},
+    {absl::StatusCode::kAborted, absl::AbortedError, absl::IsAborted},
+    {absl::StatusCode::kOutOfRange, absl::OutOfRangeError, absl::IsOutOfRange},
+    {absl::StatusCode::kUnimplemented, absl::UnimplementedError,
+     absl::IsUnimplemented},
+    {absl::StatusCode::kInternal, absl::InternalError, absl::IsInternal},
+    {absl::StatusCode::kUnavailable, absl::UnavailableError,
+     absl::IsUnavailable},
+    {absl::StatusCode::kDataLoss, absl::DataLossError, absl::IsDataLoss},
+    {absl::StatusCode::kUnauthenticated, absl::UnauthenticatedError,
+     absl::IsUnauthenticated},
+};
+
+TEST(Status, CreateAndClassify) {
+  for (const auto& test : kErrorTests) {
+    SCOPED_TRACE(absl::StatusCodeToString(test.code));
+
+    // Ensure that the creator does, in fact, create status objects with the
+    // expected error code and message.
+    std::string message =
+        absl::StrCat("error code ", test.code, " test message");
+    absl::Status status = test.creator(message);
+    EXPECT_EQ(test.code, status.code());
+    EXPECT_EQ(message, status.message());
+
+    // Ensure that the classifier returns true for a status produced by the
+    // creator.
+    EXPECT_TRUE(test.classifier(status));
+
+    // Ensure that the classifier returns false for status with a different
+    // code.
+    for (const auto& other : kErrorTests) {
+      if (other.code != test.code) {
+        EXPECT_FALSE(test.classifier(absl::Status(other.code, "")))
+            << " other.code = " << other.code;
+      }
+    }
+  }
+}
+
+TEST(Status, DefaultConstructor) {
+  absl::Status status;
+  EXPECT_TRUE(status.ok());
+  EXPECT_EQ(absl::StatusCode::kOk, status.code());
+  EXPECT_EQ("", status.message());
+}
+
+TEST(Status, OkStatus) {
+  absl::Status status = absl::OkStatus();
+  EXPECT_TRUE(status.ok());
+  EXPECT_EQ(absl::StatusCode::kOk, status.code());
+  EXPECT_EQ("", status.message());
+}
+
+TEST(Status, ConstructorWithCodeMessage) {
+  {
+    absl::Status status(absl::StatusCode::kCancelled, "");
+    EXPECT_FALSE(status.ok());
+    EXPECT_EQ(absl::StatusCode::kCancelled, status.code());
+    EXPECT_EQ("", status.message());
+  }
+  {
+    absl::Status status(absl::StatusCode::kInternal, "message");
+    EXPECT_FALSE(status.ok());
+    EXPECT_EQ(absl::StatusCode::kInternal, status.code());
+    EXPECT_EQ("message", status.message());
+  }
+}
+
+TEST(Status, ConstructOutOfRangeCode) {
+  const int kRawCode = 9999;
+  absl::Status status(static_cast<absl::StatusCode>(kRawCode), "");
+  EXPECT_EQ(absl::StatusCode::kUnknown, status.code());
+  EXPECT_EQ(kRawCode, status.raw_code());
+}
+
+constexpr char kUrl1[] = "url.payload.1";
+constexpr char kUrl2[] = "url.payload.2";
+constexpr char kUrl3[] = "url.payload.3";
+constexpr char kUrl4[] = "url.payload.xx";
+
+constexpr char kPayload1[] = "aaaaa";
+constexpr char kPayload2[] = "bbbbb";
+constexpr char kPayload3[] = "ccccc";
+
+using PayloadsVec = std::vector<std::pair<std::string, absl::Cord>>;
+
+TEST(Status, TestGetSetPayload) {
+  absl::Status ok_status = absl::OkStatus();
+  ok_status.SetPayload(kUrl1, absl::Cord(kPayload1));
+  ok_status.SetPayload(kUrl2, absl::Cord(kPayload2));
+
+  EXPECT_FALSE(ok_status.GetPayload(kUrl1));
+  EXPECT_FALSE(ok_status.GetPayload(kUrl2));
+
+  absl::Status bad_status(absl::StatusCode::kInternal, "fail");
+  bad_status.SetPayload(kUrl1, absl::Cord(kPayload1));
+  bad_status.SetPayload(kUrl2, absl::Cord(kPayload2));
+
+  EXPECT_THAT(bad_status.GetPayload(kUrl1), Optional(Eq(kPayload1)));
+  EXPECT_THAT(bad_status.GetPayload(kUrl2), Optional(Eq(kPayload2)));
+
+  EXPECT_FALSE(bad_status.GetPayload(kUrl3));
+
+  bad_status.SetPayload(kUrl1, absl::Cord(kPayload3));
+  EXPECT_THAT(bad_status.GetPayload(kUrl1), Optional(Eq(kPayload3)));
+
+  // Testing dynamically generated type_url
+  bad_status.SetPayload(absl::StrCat(kUrl1, ".1"), absl::Cord(kPayload1));
+  EXPECT_THAT(bad_status.GetPayload(absl::StrCat(kUrl1, ".1")),
+              Optional(Eq(kPayload1)));
+}
+
+TEST(Status, TestErasePayload) {
+  absl::Status bad_status(absl::StatusCode::kInternal, "fail");
+  bad_status.SetPayload(kUrl1, absl::Cord(kPayload1));
+  bad_status.SetPayload(kUrl2, absl::Cord(kPayload2));
+  bad_status.SetPayload(kUrl3, absl::Cord(kPayload3));
+
+  EXPECT_FALSE(bad_status.ErasePayload(kUrl4));
+
+  EXPECT_TRUE(bad_status.GetPayload(kUrl2));
+  EXPECT_TRUE(bad_status.ErasePayload(kUrl2));
+  EXPECT_FALSE(bad_status.GetPayload(kUrl2));
+  EXPECT_FALSE(bad_status.ErasePayload(kUrl2));
+
+  EXPECT_TRUE(bad_status.ErasePayload(kUrl1));
+  EXPECT_TRUE(bad_status.ErasePayload(kUrl3));
+
+  bad_status.SetPayload(kUrl1, absl::Cord(kPayload1));
+  EXPECT_TRUE(bad_status.ErasePayload(kUrl1));
+}
+
+TEST(Status, TestComparePayloads) {
+  absl::Status bad_status1(absl::StatusCode::kInternal, "fail");
+  bad_status1.SetPayload(kUrl1, absl::Cord(kPayload1));
+  bad_status1.SetPayload(kUrl2, absl::Cord(kPayload2));
+  bad_status1.SetPayload(kUrl3, absl::Cord(kPayload3));
+
+  absl::Status bad_status2(absl::StatusCode::kInternal, "fail");
+  bad_status2.SetPayload(kUrl2, absl::Cord(kPayload2));
+  bad_status2.SetPayload(kUrl3, absl::Cord(kPayload3));
+  bad_status2.SetPayload(kUrl1, absl::Cord(kPayload1));
+
+  EXPECT_EQ(bad_status1, bad_status2);
+}
+
+TEST(Status, TestComparePayloadsAfterErase) {
+  absl::Status payload_status(absl::StatusCode::kInternal, "");
+  payload_status.SetPayload(kUrl1, absl::Cord(kPayload1));
+  payload_status.SetPayload(kUrl2, absl::Cord(kPayload2));
+
+  absl::Status empty_status(absl::StatusCode::kInternal, "");
+
+  // Different payloads, not equal
+  EXPECT_NE(payload_status, empty_status);
+  EXPECT_TRUE(payload_status.ErasePayload(kUrl1));
+
+  // Still Different payloads, still not equal.
+  EXPECT_NE(payload_status, empty_status);
+  EXPECT_TRUE(payload_status.ErasePayload(kUrl2));
+
+  // Both empty payloads, should be equal
+  EXPECT_EQ(payload_status, empty_status);
+}
+
+PayloadsVec AllVisitedPayloads(const absl::Status& s) {
+  PayloadsVec result;
+
+  s.ForEachPayload([&](absl::string_view type_url, const absl::Cord& payload) {
+    result.push_back(std::make_pair(std::string(type_url), payload));
+  });
+
+  return result;
+}
+
+TEST(Status, TestForEachPayload) {
+  absl::Status bad_status(absl::StatusCode::kInternal, "fail");
+  bad_status.SetPayload(kUrl1, absl::Cord(kPayload1));
+  bad_status.SetPayload(kUrl2, absl::Cord(kPayload2));
+  bad_status.SetPayload(kUrl3, absl::Cord(kPayload3));
+
+  int count = 0;
+
+  bad_status.ForEachPayload(
+      [&count](absl::string_view, const absl::Cord&) { ++count; });
+
+  EXPECT_EQ(count, 3);
+
+  PayloadsVec expected_payloads = {{kUrl1, absl::Cord(kPayload1)},
+                                   {kUrl2, absl::Cord(kPayload2)},
+                                   {kUrl3, absl::Cord(kPayload3)}};
+
+  // Test that we visit all the payloads in the status.
+  PayloadsVec visited_payloads = AllVisitedPayloads(bad_status);
+  EXPECT_THAT(visited_payloads, UnorderedElementsAreArray(expected_payloads));
+
+  // Test that visitation order is not consistent between run.
+  std::vector<absl::Status> scratch;
+  while (true) {
+    scratch.emplace_back(absl::StatusCode::kInternal, "fail");
+
+    scratch.back().SetPayload(kUrl1, absl::Cord(kPayload1));
+    scratch.back().SetPayload(kUrl2, absl::Cord(kPayload2));
+    scratch.back().SetPayload(kUrl3, absl::Cord(kPayload3));
+
+    if (AllVisitedPayloads(scratch.back()) != visited_payloads) {
+      break;
+    }
+  }
+}
+
+TEST(Status, ToString) {
+  absl::Status s(absl::StatusCode::kInternal, "fail");
+  EXPECT_EQ("INTERNAL: fail", s.ToString());
+  s.SetPayload("foo", absl::Cord("bar"));
+  EXPECT_EQ("INTERNAL: fail [foo='bar']", s.ToString());
+  s.SetPayload("bar", absl::Cord("\377"));
+  EXPECT_THAT(s.ToString(),
+              AllOf(HasSubstr("INTERNAL: fail"), HasSubstr("[foo='bar']"),
+                    HasSubstr("[bar='\\xff']")));
+}
+
+absl::Status EraseAndReturn(const absl::Status& base) {
+  absl::Status copy = base;
+  EXPECT_TRUE(copy.ErasePayload(kUrl1));
+  return copy;
+}
+
+TEST(Status, CopyOnWriteForErasePayload) {
+  {
+    absl::Status base(absl::StatusCode::kInvalidArgument, "fail");
+    base.SetPayload(kUrl1, absl::Cord(kPayload1));
+    EXPECT_TRUE(base.GetPayload(kUrl1).has_value());
+    absl::Status copy = EraseAndReturn(base);
+    EXPECT_TRUE(base.GetPayload(kUrl1).has_value());
+    EXPECT_FALSE(copy.GetPayload(kUrl1).has_value());
+  }
+  {
+    absl::Status base(absl::StatusCode::kInvalidArgument, "fail");
+    base.SetPayload(kUrl1, absl::Cord(kPayload1));
+    absl::Status copy = base;
+
+    EXPECT_TRUE(base.GetPayload(kUrl1).has_value());
+    EXPECT_TRUE(copy.GetPayload(kUrl1).has_value());
+
+    EXPECT_TRUE(base.ErasePayload(kUrl1));
+
+    EXPECT_FALSE(base.GetPayload(kUrl1).has_value());
+    EXPECT_TRUE(copy.GetPayload(kUrl1).has_value());
+  }
+}
+
+TEST(Status, CopyConstructor) {
+  {
+    absl::Status status;
+    absl::Status copy(status);
+    EXPECT_EQ(copy, status);
+  }
+  {
+    absl::Status status(absl::StatusCode::kInvalidArgument, "message");
+    absl::Status copy(status);
+    EXPECT_EQ(copy, status);
+  }
+  {
+    absl::Status status(absl::StatusCode::kInvalidArgument, "message");
+    status.SetPayload(kUrl1, absl::Cord(kPayload1));
+    absl::Status copy(status);
+    EXPECT_EQ(copy, status);
+  }
+}
+
+TEST(Status, CopyAssignment) {
+  absl::Status assignee;
+  {
+    absl::Status status;
+    assignee = status;
+    EXPECT_EQ(assignee, status);
+  }
+  {
+    absl::Status status(absl::StatusCode::kInvalidArgument, "message");
+    assignee = status;
+    EXPECT_EQ(assignee, status);
+  }
+  {
+    absl::Status status(absl::StatusCode::kInvalidArgument, "message");
+    status.SetPayload(kUrl1, absl::Cord(kPayload1));
+    assignee = status;
+    EXPECT_EQ(assignee, status);
+  }
+}
+
+TEST(Status, CopyAssignmentIsNotRef) {
+  const absl::Status status_orig(absl::StatusCode::kInvalidArgument, "message");
+  absl::Status status_copy = status_orig;
+  EXPECT_EQ(status_orig, status_copy);
+  status_copy.SetPayload(kUrl1, absl::Cord(kPayload1));
+  EXPECT_NE(status_orig, status_copy);
+}
+
+TEST(Status, MoveConstructor) {
+  {
+    absl::Status status;
+    absl::Status copy(absl::Status{});
+    EXPECT_EQ(copy, status);
+  }
+  {
+    absl::Status status(absl::StatusCode::kInvalidArgument, "message");
+    absl::Status copy(
+        absl::Status(absl::StatusCode::kInvalidArgument, "message"));
+    EXPECT_EQ(copy, status);
+  }
+  {
+    absl::Status status(absl::StatusCode::kInvalidArgument, "message");
+    status.SetPayload(kUrl1, absl::Cord(kPayload1));
+    absl::Status copy1(status);
+    absl::Status copy2(std::move(status));
+    EXPECT_EQ(copy1, copy2);
+  }
+}
+
+TEST(Status, MoveAssignment) {
+  absl::Status assignee;
+  {
+    absl::Status status;
+    assignee = absl::Status();
+    EXPECT_EQ(assignee, status);
+  }
+  {
+    absl::Status status(absl::StatusCode::kInvalidArgument, "message");
+    assignee = absl::Status(absl::StatusCode::kInvalidArgument, "message");
+    EXPECT_EQ(assignee, status);
+  }
+  {
+    absl::Status status(absl::StatusCode::kInvalidArgument, "message");
+    status.SetPayload(kUrl1, absl::Cord(kPayload1));
+    absl::Status copy(status);
+    assignee = std::move(status);
+    EXPECT_EQ(assignee, copy);
+  }
+}
+
+TEST(Status, Update) {
+  absl::Status s;
+  s.Update(absl::OkStatus());
+  EXPECT_TRUE(s.ok());
+  const absl::Status a(absl::StatusCode::kCancelled, "message");
+  s.Update(a);
+  EXPECT_EQ(s, a);
+  const absl::Status b(absl::StatusCode::kInternal, "other message");
+  s.Update(b);
+  EXPECT_EQ(s, a);
+  s.Update(absl::OkStatus());
+  EXPECT_EQ(s, a);
+  EXPECT_FALSE(s.ok());
+}
+
+TEST(Status, Equality) {
+  absl::Status ok;
+  absl::Status no_payload = absl::CancelledError("no payload");
+  absl::Status one_payload = absl::InvalidArgumentError("one payload");
+  one_payload.SetPayload(kUrl1, absl::Cord(kPayload1));
+  absl::Status two_payloads = one_payload;
+  two_payloads.SetPayload(kUrl2, absl::Cord(kPayload2));
+  const std::array<absl::Status, 4> status_arr = {ok, no_payload, one_payload,
+                                                  two_payloads};
+  for (int i = 0; i < status_arr.size(); i++) {
+    for (int j = 0; j < status_arr.size(); j++) {
+      if (i == j) {
+        EXPECT_TRUE(status_arr[i] == status_arr[j]);
+        EXPECT_FALSE(status_arr[i] != status_arr[j]);
+      } else {
+        EXPECT_TRUE(status_arr[i] != status_arr[j]);
+        EXPECT_FALSE(status_arr[i] == status_arr[j]);
+      }
+    }
+  }
+}
+
+TEST(Status, Swap) {
+  auto test_swap = [](const absl::Status& s1, const absl::Status& s2) {
+    absl::Status copy1 = s1, copy2 = s2;
+    swap(copy1, copy2);
+    EXPECT_EQ(copy1, s2);
+    EXPECT_EQ(copy2, s1);
+  };
+  const absl::Status ok;
+  const absl::Status no_payload(absl::StatusCode::kAlreadyExists, "no payload");
+  absl::Status with_payload(absl::StatusCode::kInternal, "with payload");
+  with_payload.SetPayload(kUrl1, absl::Cord(kPayload1));
+  test_swap(ok, no_payload);
+  test_swap(no_payload, ok);
+  test_swap(ok, with_payload);
+  test_swap(with_payload, ok);
+  test_swap(no_payload, with_payload);
+  test_swap(with_payload, no_payload);
+}
+
+}  // namespace
diff --git a/third_party/abseil_cpp/absl/status/statusor.cc b/third_party/abseil_cpp/absl/status/statusor.cc
new file mode 100644
index 000000000000..b954b45e32c7
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/statusor.cc
@@ -0,0 +1,71 @@
+// Copyright 2020 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/status/statusor.h"
+
+#include <cstdlib>
+#include <utility>
+
+#include "absl/base/internal/raw_logging.h"
+#include "absl/status/status.h"
+#include "absl/strings/str_cat.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+
+BadStatusOrAccess::BadStatusOrAccess(absl::Status status)
+    : status_(std::move(status)) {}
+
+BadStatusOrAccess::~BadStatusOrAccess() = default;
+const char* BadStatusOrAccess::what() const noexcept {
+  return "Bad StatusOr access";
+}
+
+const absl::Status& BadStatusOrAccess::status() const { return status_; }
+
+namespace internal_statusor {
+
+void Helper::HandleInvalidStatusCtorArg(absl::Status* status) {
+  const char* kMessage =
+      "An OK status is not a valid constructor argument to StatusOr<T>";
+#ifdef NDEBUG
+  ABSL_INTERNAL_LOG(ERROR, kMessage);
+#else
+  ABSL_INTERNAL_LOG(FATAL, kMessage);
+#endif
+  // In optimized builds, we will fall back to InternalError.
+  *status = absl::InternalError(kMessage);
+}
+
+void Helper::Crash(const absl::Status& status) {
+  ABSL_INTERNAL_LOG(
+      FATAL,
+      absl::StrCat("Attempting to fetch value instead of handling error ",
+                   status.ToString()));
+}
+
+void ThrowBadStatusOrAccess(absl::Status status) {
+#ifdef ABSL_HAVE_EXCEPTIONS
+  throw absl::BadStatusOrAccess(std::move(status));
+#else
+  ABSL_INTERNAL_LOG(
+      FATAL,
+      absl::StrCat("Attempting to fetch value instead of handling error ",
+                   status.ToString()));
+  std::abort();
+#endif
+}
+
+}  // namespace internal_statusor
+ABSL_NAMESPACE_END
+}  // namespace absl
diff --git a/third_party/abseil_cpp/absl/status/statusor.h b/third_party/abseil_cpp/absl/status/statusor.h
new file mode 100644
index 000000000000..469d486fdd2e
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/statusor.h
@@ -0,0 +1,760 @@
+// Copyright 2020 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.
+//
+// -----------------------------------------------------------------------------
+// File: statusor.h
+// -----------------------------------------------------------------------------
+//
+// An `absl::StatusOr<T>` represents a union of an `absl::Status` object
+// and an object of type `T`. The `absl::StatusOr<T>` will either contain an
+// object of type `T` (indicating a successful operation), or an error (of type
+// `absl::Status`) explaining why such a value is not present.
+//
+// In general, check the success of an operation returning an
+// `absl::StatusOr<T>` like you would an `absl::Status` by using the `ok()`
+// member function.
+//
+// Example:
+//
+//   StatusOr<Foo> result = Calculation();
+//   if (result.ok()) {
+//     result->DoSomethingCool();
+//   } else {
+//     LOG(ERROR) << result.status();
+//   }
+#ifndef ABSL_STATUS_STATUSOR_H_
+#define ABSL_STATUS_STATUSOR_H_
+
+#include <exception>
+#include <initializer_list>
+#include <new>
+#include <string>
+#include <type_traits>
+#include <utility>
+
+#include "absl/base/attributes.h"
+#include "absl/meta/type_traits.h"
+#include "absl/status/internal/statusor_internal.h"
+#include "absl/status/status.h"
+#include "absl/types/variant.h"
+#include "absl/utility/utility.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+
+// BadStatusOrAccess
+//
+// This class defines the type of object to throw (if exceptions are enabled),
+// when accessing the value of an `absl::StatusOr<T>` object that does not
+// contain a value. This behavior is analogous to that of
+// `std::bad_optional_access` in the case of accessing an invalid
+// `std::optional` value.
+//
+// Example:
+//
+// try {
+//   absl::StatusOr<int> v = FetchInt();
+//   DoWork(v.value());  // Accessing value() when not "OK" may throw
+// } catch (absl::BadStatusOrAccess& ex) {
+//   LOG(ERROR) << ex.status();
+// }
+class BadStatusOrAccess : public std::exception {
+ public:
+  explicit BadStatusOrAccess(absl::Status status);
+  ~BadStatusOrAccess() override;
+
+  // BadStatusOrAccess::what()
+  //
+  // Returns the associated explanatory string of the `absl::StatusOr<T>`
+  // object's error code. This function only returns the string literal "Bad
+  // StatusOr Access" for cases when evaluating general exceptions.
+  //
+  // The pointer of this string is guaranteed to be valid until any non-const
+  // function is invoked on the exception object.
+  const char* what() const noexcept override;
+
+  // BadStatusOrAccess::status()
+  //
+  // Returns the associated `absl::Status` of the `absl::StatusOr<T>` object's
+  // error.
+  const absl::Status& status() const;
+
+ private:
+  absl::Status status_;
+};
+
+// Returned StatusOr objects may not be ignored.
+template <typename T>
+class ABSL_MUST_USE_RESULT StatusOr;
+
+// absl::StatusOr<T>
+//
+// The `absl::StatusOr<T>` class template is a union of an `absl::Status` object
+// and an object of type `T`. The `absl::StatusOr<T>` models an object that is
+// either a usable object, or an error (of type `absl::Status`) explaining why
+// such an object is not present. An `absl::StatusOr<T>` is typically the return
+// value of a function which may fail.
+//
+// An `absl::StatusOr<T>` can never hold an "OK" status (an
+// `absl::StatusCode::kOk` value); instead, the presence of an object of type
+// `T` indicates success. Instead of checking for a `kOk` value, use the
+// `absl::StatusOr<T>::ok()` member function. (It is for this reason, and code
+// readability, that using the `ok()` function is preferred for `absl::Status`
+// as well.)
+//
+// Example:
+//
+//   StatusOr<Foo> result = DoBigCalculationThatCouldFail();
+//   if (result.ok()) {
+//     result->DoSomethingCool();
+//   } else {
+//     LOG(ERROR) << result.status();
+//   }
+//
+// Accessing the object held by an `absl::StatusOr<T>` should be performed via
+// `operator*` or `operator->`, after a call to `ok()` confirms that the
+// `absl::StatusOr<T>` holds an object of type `T`:
+//
+// Example:
+//
+//   absl::StatusOr<int> i = GetCount();
+//   if (i.ok()) {
+//     updated_total += *i
+//   }
+//
+// NOTE: using `absl::StatusOr<T>::value()` when no valid value is present will
+// throw an exception if exceptions are enabled or terminate the process when
+// execeptions are not enabled.
+//
+// Example:
+//
+//   StatusOr<Foo> result = DoBigCalculationThatCouldFail();
+//   const Foo& foo = result.value();    // Crash/exception if no value present
+//   foo.DoSomethingCool();
+//
+// A `absl::StatusOr<T*>` can be constructed from a null pointer like any other
+// pointer value, and the result will be that `ok()` returns `true` and
+// `value()` returns `nullptr`. Checking the value of pointer in an
+// `absl::StatusOr<T>` generally requires a bit more care, to ensure both that a
+// value is present and that value is not null:
+//
+//  StatusOr<std::unique_ptr<Foo>> result = FooFactory::MakeNewFoo(arg);
+//  if (!result.ok()) {
+//    LOG(ERROR) << result.status();
+//  } else if (*result == nullptr) {
+//    LOG(ERROR) << "Unexpected null pointer";
+//  } else {
+//    (*result)->DoSomethingCool();
+//  }
+//
+// Example factory implementation returning StatusOr<T>:
+//
+//  StatusOr<Foo> FooFactory::MakeFoo(int arg) {
+//    if (arg <= 0) {
+//      return absl::Status(absl::StatusCode::kInvalidArgument,
+//                          "Arg must be positive");
+//    }
+//    return Foo(arg);
+//  }
+template <typename T>
+class StatusOr : private internal_statusor::StatusOrData<T>,
+                 private internal_statusor::CopyCtorBase<T>,
+                 private internal_statusor::MoveCtorBase<T>,
+                 private internal_statusor::CopyAssignBase<T>,
+                 private internal_statusor::MoveAssignBase<T> {
+  template <typename U>
+  friend class StatusOr;
+
+  typedef internal_statusor::StatusOrData<T> Base;
+
+ public:
+  // StatusOr<T>::value_type
+  //
+  // This instance data provides a generic `value_type` member for use within
+  // generic programming. This usage is analogous to that of
+  // `optional::value_type` in the case of `std::optional`.
+  typedef T value_type;
+
+  // Constructors
+
+  // Constructs a new `absl::StatusOr` with an `absl::StatusCode::kUnknown`
+  // status. This constructor is marked 'explicit' to prevent usages in return
+  // values such as 'return {};', under the misconception that
+  // `absl::StatusOr<std::vector<int>>` will be initialized with an empty
+  // vector, instead of an `absl::StatusCode::kUnknown` error code.
+  explicit StatusOr();
+
+  // `StatusOr<T>` is copy constructible if `T` is copy constructible.
+  StatusOr(const StatusOr&) = default;
+  // `StatusOr<T>` is copy assignable if `T` is copy constructible and copy
+  // assignable.
+  StatusOr& operator=(const StatusOr&) = default;
+
+  // `StatusOr<T>` is move constructible if `T` is move constructible.
+  StatusOr(StatusOr&&) = default;
+  // `StatusOr<T>` is moveAssignable if `T` is move constructible and move
+  // assignable.
+  StatusOr& operator=(StatusOr&&) = default;
+
+  // Converting Constructors
+
+  // Constructs a new `absl::StatusOr<T>` from an `absl::StatusOr<U>`, when `T`
+  // is constructible from `U`. To avoid ambiguity, these constructors are
+  // disabled if `T` is also constructible from `StatusOr<U>.`. This constructor
+  // is explicit if and only if the corresponding construction of `T` from `U`
+  // is explicit. (This constructor inherits its explicitness from the
+  // underlying constructor.)
+  template <
+      typename U,
+      absl::enable_if_t<
+          absl::conjunction<
+              absl::negation<std::is_same<T, U>>,
+              std::is_constructible<T, const U&>,
+              std::is_convertible<const U&, T>,
+              absl::negation<
+                  internal_statusor::IsConstructibleOrConvertibleFromStatusOr<
+                      T, U>>>::value,
+          int> = 0>
+  StatusOr(const StatusOr<U>& other)  // NOLINT
+      : Base(static_cast<const typename StatusOr<U>::Base&>(other)) {}
+  template <
+      typename U,
+      absl::enable_if_t<
+          absl::conjunction<
+              absl::negation<std::is_same<T, U>>,
+              std::is_constructible<T, const U&>,
+              absl::negation<std::is_convertible<const U&, T>>,
+              absl::negation<
+                  internal_statusor::IsConstructibleOrConvertibleFromStatusOr<
+                      T, U>>>::value,
+          int> = 0>
+  explicit StatusOr(const StatusOr<U>& other)
+      : Base(static_cast<const typename StatusOr<U>::Base&>(other)) {}
+
+  template <
+      typename U,
+      absl::enable_if_t<
+          absl::conjunction<
+              absl::negation<std::is_same<T, U>>, std::is_constructible<T, U&&>,
+              std::is_convertible<U&&, T>,
+              absl::negation<
+                  internal_statusor::IsConstructibleOrConvertibleFromStatusOr<
+                      T, U>>>::value,
+          int> = 0>
+  StatusOr(StatusOr<U>&& other)  // NOLINT
+      : Base(static_cast<typename StatusOr<U>::Base&&>(other)) {}
+  template <
+      typename U,
+      absl::enable_if_t<
+          absl::conjunction<
+              absl::negation<std::is_same<T, U>>, std::is_constructible<T, U&&>,
+              absl::negation<std::is_convertible<U&&, T>>,
+              absl::negation<
+                  internal_statusor::IsConstructibleOrConvertibleFromStatusOr<
+                      T, U>>>::value,
+          int> = 0>
+  explicit StatusOr(StatusOr<U>&& other)
+      : Base(static_cast<typename StatusOr<U>::Base&&>(other)) {}
+
+  // Converting Assignment Operators
+
+  // Creates an `absl::StatusOr<T>` through assignment from an
+  // `absl::StatusOr<U>` when:
+  //
+  //   * Both `absl::StatusOr<T>` and `absl::StatusOr<U>` are OK by assigning
+  //     `U` to `T` directly.
+  //   * `absl::StatusOr<T>` is OK and `absl::StatusOr<U>` contains an error
+  //      code by destroying `absl::StatusOr<T>`'s value and assigning from
+  //      `absl::StatusOr<U>'
+  //   * `absl::StatusOr<T>` contains an error code and `absl::StatusOr<U>` is
+  //      OK by directly initializing `T` from `U`.
+  //   * Both `absl::StatusOr<T>` and `absl::StatusOr<U>` contain an error
+  //     code by assigning the `Status` in `absl::StatusOr<U>` to
+  //     `absl::StatusOr<T>`
+  //
+  // These overloads only apply if `absl::StatusOr<T>` is constructible and
+  // assignable from `absl::StatusOr<U>` and `StatusOr<T>` cannot be directly
+  // assigned from `StatusOr<U>`.
+  template <
+      typename U,
+      absl::enable_if_t<
+          absl::conjunction<
+              absl::negation<std::is_same<T, U>>,
+              std::is_constructible<T, const U&>,
+              std::is_assignable<T, const U&>,
+              absl::negation<
+                  internal_statusor::
+                      IsConstructibleOrConvertibleOrAssignableFromStatusOr<
+                          T, U>>>::value,
+          int> = 0>
+  StatusOr& operator=(const StatusOr<U>& other) {
+    this->Assign(other);
+    return *this;
+  }
+  template <
+      typename U,
+      absl::enable_if_t<
+          absl::conjunction<
+              absl::negation<std::is_same<T, U>>, std::is_constructible<T, U&&>,
+              std::is_assignable<T, U&&>,
+              absl::negation<
+                  internal_statusor::
+                      IsConstructibleOrConvertibleOrAssignableFromStatusOr<
+                          T, U>>>::value,
+          int> = 0>
+  StatusOr& operator=(StatusOr<U>&& other) {
+    this->Assign(std::move(other));
+    return *this;
+  }
+
+  // Constructs a new `absl::StatusOr<T>` with a non-ok status. After calling
+  // this constructor, `this->ok()` will be `false` and calls to `value()` will
+  // crash, or produce an exception if exceptions are enabled.
+  //
+  // The constructor also takes any type `U` that is convertible to
+  // `absl::Status`. This constructor is explicit if an only if `U` is not of
+  // type `absl::Status` and the conversion from `U` to `Status` is explicit.
+  //
+  // REQUIRES: !Status(std::forward<U>(v)).ok(). This requirement is DCHECKed.
+  // In optimized builds, passing absl::OkStatus() here will have the effect
+  // of passing absl::StatusCode::kInternal as a fallback.
+  template <
+      typename U = absl::Status,
+      absl::enable_if_t<
+          absl::conjunction<
+              std::is_convertible<U&&, absl::Status>,
+              std::is_constructible<absl::Status, U&&>,
+              absl::negation<std::is_same<absl::decay_t<U>, absl::StatusOr<T>>>,
+              absl::negation<std::is_same<absl::decay_t<U>, T>>,
+              absl::negation<std::is_same<absl::decay_t<U>, absl::in_place_t>>,
+              absl::negation<internal_statusor::HasConversionOperatorToStatusOr<
+                  T, U&&>>>::value,
+          int> = 0>
+  StatusOr(U&& v) : Base(std::forward<U>(v)) {}
+
+  template <
+      typename U = absl::Status,
+      absl::enable_if_t<
+          absl::conjunction<
+              absl::negation<std::is_convertible<U&&, absl::Status>>,
+              std::is_constructible<absl::Status, U&&>,
+              absl::negation<std::is_same<absl::decay_t<U>, absl::StatusOr<T>>>,
+              absl::negation<std::is_same<absl::decay_t<U>, T>>,
+              absl::negation<std::is_same<absl::decay_t<U>, absl::in_place_t>>,
+              absl::negation<internal_statusor::HasConversionOperatorToStatusOr<
+                  T, U&&>>>::value,
+          int> = 0>
+  explicit StatusOr(U&& v) : Base(std::forward<U>(v)) {}
+
+  template <
+      typename U = absl::Status,
+      absl::enable_if_t<
+          absl::conjunction<
+              std::is_convertible<U&&, absl::Status>,
+              std::is_constructible<absl::Status, U&&>,
+              absl::negation<std::is_same<absl::decay_t<U>, absl::StatusOr<T>>>,
+              absl::negation<std::is_same<absl::decay_t<U>, T>>,
+              absl::negation<std::is_same<absl::decay_t<U>, absl::in_place_t>>,
+              absl::negation<internal_statusor::HasConversionOperatorToStatusOr<
+                  T, U&&>>>::value,
+          int> = 0>
+  StatusOr& operator=(U&& v) {
+    this->AssignStatus(std::forward<U>(v));
+    return *this;
+  }
+
+  // Perfect-forwarding value assignment operator.
+
+  // If `*this` contains a `T` value before the call, the contained value is
+  // assigned from `std::forward<U>(v)`; Otherwise, it is directly-initialized
+  // from `std::forward<U>(v)`.
+  // This function does not participate in overload unless:
+  // 1. `std::is_constructible_v<T, U>` is true,
+  // 2. `std::is_assignable_v<T&, U>` is true.
+  // 3. `std::is_same_v<StatusOr<T>, std::remove_cvref_t<U>>` is false.
+  // 4. Assigning `U` to `T` is not ambiguous:
+  //  If `U` is `StatusOr<V>` and `T` is constructible and assignable from
+  //  both `StatusOr<V>` and `V`, the assignment is considered bug-prone and
+  //  ambiguous thus will fail to compile. For example:
+  //    StatusOr<bool> s1 = true;  // s1.ok() && *s1 == true
+  //    StatusOr<bool> s2 = false;  // s2.ok() && *s2 == false
+  //    s1 = s2;  // ambiguous, `s1 = *s2` or `s1 = bool(s2)`?
+  template <
+      typename U = T,
+      typename = typename std::enable_if<absl::conjunction<
+          std::is_constructible<T, U&&>, std::is_assignable<T&, U&&>,
+          absl::disjunction<
+              std::is_same<absl::remove_cv_t<absl::remove_reference_t<U>>, T>,
+              absl::conjunction<
+                  absl::negation<std::is_convertible<U&&, absl::Status>>,
+                  absl::negation<internal_statusor::
+                                     HasConversionOperatorToStatusOr<T, U&&>>>>,
+          internal_statusor::IsForwardingAssignmentValid<T, U&&>>::value>::type>
+  StatusOr& operator=(U&& v) {
+    this->Assign(std::forward<U>(v));
+    return *this;
+  }
+
+  // Constructs the inner value `T` in-place using the provided args, using the
+  // `T(args...)` constructor.
+  template <typename... Args>
+  explicit StatusOr(absl::in_place_t, Args&&... args);
+  template <typename U, typename... Args>
+  explicit StatusOr(absl::in_place_t, std::initializer_list<U> ilist,
+                    Args&&... args);
+
+  // Constructs the inner value `T` in-place using the provided args, using the
+  // `T(U)` (direct-initialization) constructor. This constructor is only valid
+  // if `T` can be constructed from a `U`. Can accept move or copy constructors.
+  //
+  // This constructor is explicit if `U` is not convertible to `T`. To avoid
+  // ambiguity, this constuctor is disabled if `U` is a `StatusOr<J>`, where `J`
+  // is convertible to `T`.
+  template <
+      typename U = T,
+      absl::enable_if_t<
+          absl::conjunction<
+              internal_statusor::IsDirectInitializationValid<T, U&&>,
+              std::is_constructible<T, U&&>, std::is_convertible<U&&, T>,
+              absl::disjunction<
+                  std::is_same<absl::remove_cv_t<absl::remove_reference_t<U>>,
+                               T>,
+                  absl::conjunction<
+                      absl::negation<std::is_convertible<U&&, absl::Status>>,
+                      absl::negation<
+                          internal_statusor::HasConversionOperatorToStatusOr<
+                              T, U&&>>>>>::value,
+          int> = 0>
+  StatusOr(U&& u)  // NOLINT
+      : StatusOr(absl::in_place, std::forward<U>(u)) {
+  }
+
+  template <
+      typename U = T,
+      absl::enable_if_t<
+          absl::conjunction<
+              internal_statusor::IsDirectInitializationValid<T, U&&>,
+              absl::disjunction<
+                  std::is_same<absl::remove_cv_t<absl::remove_reference_t<U>>,
+                               T>,
+                  absl::conjunction<
+                      absl::negation<std::is_constructible<absl::Status, U&&>>,
+                      absl::negation<
+                          internal_statusor::HasConversionOperatorToStatusOr<
+                              T, U&&>>>>,
+              std::is_constructible<T, U&&>,
+              absl::negation<std::is_convertible<U&&, T>>>::value,
+          int> = 0>
+  explicit StatusOr(U&& u)  // NOLINT
+      : StatusOr(absl::in_place, std::forward<U>(u)) {
+  }
+
+  // StatusOr<T>::ok()
+  //
+  // Returns whether or not this `absl::StatusOr<T>` holds a `T` value. This
+  // member function is analagous to `absl::Status::ok()` and should be used
+  // similarly to check the status of return values.
+  //
+  // Example:
+  //
+  // StatusOr<Foo> result = DoBigCalculationThatCouldFail();
+  // if (result.ok()) {
+  //    // Handle result
+  // else {
+  //    // Handle error
+  // }
+  ABSL_MUST_USE_RESULT bool ok() const { return this->status_.ok(); }
+
+  // StatusOr<T>::status()
+  //
+  // Returns a reference to the current `absl::Status` contained within the
+  // `absl::StatusOr<T>`. If `absl::StatusOr<T>` contains a `T`, then this
+  // function returns `absl::OkStatus()`.
+  const Status& status() const &;
+  Status status() &&;
+
+  // StatusOr<T>::value()
+  //
+  // Returns a reference to the held value if `this->ok()`. Otherwise, throws
+  // `absl::BadStatusOrAccess` if exceptions are enabled, or is guaranteed to
+  // terminate the process if exceptions are disabled.
+  //
+  // If you have already checked the status using `this->ok()`, you probably
+  // want to use `operator*()` or `operator->()` to access the value instead of
+  // `value`.
+  //
+  // Note: for value types that are cheap to copy, prefer simple code:
+  //
+  //   T value = statusor.value();
+  //
+  // Otherwise, if the value type is expensive to copy, but can be left
+  // in the StatusOr, simply assign to a reference:
+  //
+  //   T& value = statusor.value();  // or `const T&`
+  //
+  // Otherwise, if the value type supports an efficient move, it can be
+  // used as follows:
+  //
+  //   T value = std::move(statusor).value();
+  //
+  // The `std::move` on statusor instead of on the whole expression enables
+  // warnings about possible uses of the statusor object after the move.
+  const T& value() const&;
+  T& value() &;
+  const T&& value() const&&;
+  T&& value() &&;
+
+  // StatusOr<T>:: operator*()
+  //
+  // Returns a reference to the current value.
+  //
+  // REQUIRES: `this->ok() == true`, otherwise the behavior is undefined.
+  //
+  // Use `this->ok()` to verify that there is a current value within the
+  // `absl::StatusOr<T>`. Alternatively, see the `value()` member function for a
+  // similar API that guarantees crashing or throwing an exception if there is
+  // no current value.
+  const T& operator*() const&;
+  T& operator*() &;
+  const T&& operator*() const&&;
+  T&& operator*() &&;
+
+  // StatusOr<T>::operator->()
+  //
+  // Returns a pointer to the current value.
+  //
+  // REQUIRES: `this->ok() == true`, otherwise the behavior is undefined.
+  //
+  // Use `this->ok()` to verify that there is a current value.
+  const T* operator->() const;
+  T* operator->();
+
+  // StatusOr<T>::value_or()
+  //
+  // Returns the current value if `this->ok() == true`. Otherwise constructs a
+  // value using the provided `default_value`.
+  //
+  // Unlike `value`, this function returns by value, copying the current value
+  // if necessary. If the value type supports an efficient move, it can be used
+  // as follows:
+  //
+  //   T value = std::move(statusor).value_or(def);
+  //
+  // Unlike with `value`, calling `std::move()` on the result of `value_or` will
+  // still trigger a copy.
+  template <typename U>
+  T value_or(U&& default_value) const&;
+  template <typename U>
+  T value_or(U&& default_value) &&;
+
+  // StatusOr<T>::IgnoreError()
+  //
+  // Ignores any errors. This method does nothing except potentially suppress
+  // complaints from any tools that are checking that errors are not dropped on
+  // the floor.
+  void IgnoreError() const;
+
+  // StatusOr<T>::emplace()
+  //
+  // Reconstructs the inner value T in-place using the provided args, using the
+  // T(args...) constructor. Returns reference to the reconstructed `T`.
+  template <typename... Args>
+  T& emplace(Args&&... args) {
+    if (ok()) {
+      this->Clear();
+      this->MakeValue(std::forward<Args>(args)...);
+    } else {
+      this->MakeValue(std::forward<Args>(args)...);
+      this->status_ = absl::OkStatus();
+    }
+    return this->data_;
+  }
+
+  template <
+      typename U, typename... Args,
+      absl::enable_if_t<
+          std::is_constructible<T, std::initializer_list<U>&, Args&&...>::value,
+          int> = 0>
+  T& emplace(std::initializer_list<U> ilist, Args&&... args) {
+    if (ok()) {
+      this->Clear();
+      this->MakeValue(ilist, std::forward<Args>(args)...);
+    } else {
+      this->MakeValue(ilist, std::forward<Args>(args)...);
+      this->status_ = absl::OkStatus();
+    }
+    return this->data_;
+  }
+
+ private:
+  using internal_statusor::StatusOrData<T>::Assign;
+  template <typename U>
+  void Assign(const absl::StatusOr<U>& other);
+  template <typename U>
+  void Assign(absl::StatusOr<U>&& other);
+};
+
+// operator==()
+//
+// This operator checks the equality of two `absl::StatusOr<T>` objects.
+template <typename T>
+bool operator==(const StatusOr<T>& lhs, const StatusOr<T>& rhs) {
+  if (lhs.ok() && rhs.ok()) return *lhs == *rhs;
+  return lhs.status() == rhs.status();
+}
+
+// operator!=()
+//
+// This operator checks the inequality of two `absl::StatusOr<T>` objects.
+template <typename T>
+bool operator!=(const StatusOr<T>& lhs, const StatusOr<T>& rhs) {
+  return !(lhs == rhs);
+}
+
+//------------------------------------------------------------------------------
+// Implementation details for StatusOr<T>
+//------------------------------------------------------------------------------
+
+// TODO(sbenza): avoid the string here completely.
+template <typename T>
+StatusOr<T>::StatusOr() : Base(Status(absl::StatusCode::kUnknown, "")) {}
+
+template <typename T>
+template <typename U>
+inline void StatusOr<T>::Assign(const StatusOr<U>& other) {
+  if (other.ok()) {
+    this->Assign(*other);
+  } else {
+    this->AssignStatus(other.status());
+  }
+}
+
+template <typename T>
+template <typename U>
+inline void StatusOr<T>::Assign(StatusOr<U>&& other) {
+  if (other.ok()) {
+    this->Assign(*std::move(other));
+  } else {
+    this->AssignStatus(std::move(other).status());
+  }
+}
+template <typename T>
+template <typename... Args>
+StatusOr<T>::StatusOr(absl::in_place_t, Args&&... args)
+    : Base(absl::in_place, std::forward<Args>(args)...) {}
+
+template <typename T>
+template <typename U, typename... Args>
+StatusOr<T>::StatusOr(absl::in_place_t, std::initializer_list<U> ilist,
+                      Args&&... args)
+    : Base(absl::in_place, ilist, std::forward<Args>(args)...) {}
+
+template <typename T>
+const Status& StatusOr<T>::status() const & { return this->status_; }
+template <typename T>
+Status StatusOr<T>::status() && {
+  return ok() ? OkStatus() : std::move(this->status_);
+}
+
+template <typename T>
+const T& StatusOr<T>::value() const& {
+  if (!this->ok()) internal_statusor::ThrowBadStatusOrAccess(this->status_);
+  return this->data_;
+}
+
+template <typename T>
+T& StatusOr<T>::value() & {
+  if (!this->ok()) internal_statusor::ThrowBadStatusOrAccess(this->status_);
+  return this->data_;
+}
+
+template <typename T>
+const T&& StatusOr<T>::value() const&& {
+  if (!this->ok()) {
+    internal_statusor::ThrowBadStatusOrAccess(std::move(this->status_));
+  }
+  return std::move(this->data_);
+}
+
+template <typename T>
+T&& StatusOr<T>::value() && {
+  if (!this->ok()) {
+    internal_statusor::ThrowBadStatusOrAccess(std::move(this->status_));
+  }
+  return std::move(this->data_);
+}
+
+template <typename T>
+const T& StatusOr<T>::operator*() const& {
+  this->EnsureOk();
+  return this->data_;
+}
+
+template <typename T>
+T& StatusOr<T>::operator*() & {
+  this->EnsureOk();
+  return this->data_;
+}
+
+template <typename T>
+const T&& StatusOr<T>::operator*() const&& {
+  this->EnsureOk();
+  return std::move(this->data_);
+}
+
+template <typename T>
+T&& StatusOr<T>::operator*() && {
+  this->EnsureOk();
+  return std::move(this->data_);
+}
+
+template <typename T>
+const T* StatusOr<T>::operator->() const {
+  this->EnsureOk();
+  return &this->data_;
+}
+
+template <typename T>
+T* StatusOr<T>::operator->() {
+  this->EnsureOk();
+  return &this->data_;
+}
+
+template <typename T>
+template <typename U>
+T StatusOr<T>::value_or(U&& default_value) const& {
+  if (ok()) {
+    return this->data_;
+  }
+  return std::forward<U>(default_value);
+}
+
+template <typename T>
+template <typename U>
+T StatusOr<T>::value_or(U&& default_value) && {
+  if (ok()) {
+    return std::move(this->data_);
+  }
+  return std::forward<U>(default_value);
+}
+
+template <typename T>
+void StatusOr<T>::IgnoreError() const {
+  // no-op
+}
+
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_STATUS_STATUSOR_H_
diff --git a/third_party/abseil_cpp/absl/status/statusor_internals.h b/third_party/abseil_cpp/absl/status/statusor_internals.h
new file mode 100644
index 000000000000..5366c2840c37
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/statusor_internals.h
@@ -0,0 +1,250 @@
+/* Copyright 2017 The TensorFlow Authors. All Rights Reserved.
+
+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
+
+    http://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.
+==============================================================================*/
+
+#ifndef ABSL_STATUS_STATUSOR_INTERNALS_H_
+#define ABSL_STATUS_STATUSOR_INTERNALS_H_
+
+#include "absl/status/status.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+
+namespace internal_statusor {
+
+class Helper {
+ public:
+  // Move type-agnostic error handling to the .cc.
+  static void HandleInvalidStatusCtorArg(Status*);
+  ABSL_ATTRIBUTE_NORETURN static void Crash(const Status& status);
+};
+
+// Construct an instance of T in `p` through placement new, passing Args... to
+// the constructor.
+// This abstraction is here mostly for the gcc performance fix.
+template <typename T, typename... Args>
+void PlacementNew(void* p, Args&&... args) {
+#if defined(__GNUC__) && !defined(__clang__)
+  // Teach gcc that 'p' cannot be null, fixing code size issues.
+  if (p == nullptr) __builtin_unreachable();
+#endif
+  new (p) T(std::forward<Args>(args)...);
+}
+
+// Helper base class to hold the data and all operations.
+// We move all this to a base class to allow mixing with the appropriate
+// TraitsBase specialization.
+template <typename T>
+class StatusOrData {
+  template <typename U>
+  friend class StatusOrData;
+
+ public:
+  StatusOrData() = delete;
+
+  StatusOrData(const StatusOrData& other) {
+    if (other.ok()) {
+      MakeValue(other.data_);
+      MakeStatus();
+    } else {
+      MakeStatus(other.status_);
+    }
+  }
+
+  StatusOrData(StatusOrData&& other) noexcept {
+    if (other.ok()) {
+      MakeValue(std::move(other.data_));
+      MakeStatus();
+    } else {
+      MakeStatus(other.status_);
+    }
+  }
+
+  template <typename U>
+  StatusOrData(const StatusOrData<U>& other) {
+    if (other.ok()) {
+      MakeValue(other.data_);
+      MakeStatus();
+    } else {
+      MakeStatus(other.status_);
+    }
+  }
+
+  template <typename U>
+  StatusOrData(StatusOrData<U>&& other) {
+    if (other.ok()) {
+      MakeValue(std::move(other.data_));
+      MakeStatus();
+    } else {
+      MakeStatus(other.status_);
+    }
+  }
+
+  explicit StatusOrData(const T& value) : data_(value) { MakeStatus(); }
+  explicit StatusOrData(T&& value) : data_(std::move(value)) { MakeStatus(); }
+
+  explicit StatusOrData(const Status& status) : status_(status) {
+    EnsureNotOk();
+  }
+  explicit StatusOrData(Status&& status) : status_(std::move(status)) {
+    EnsureNotOk();
+  }
+
+  StatusOrData& operator=(const StatusOrData& other) {
+    if (this == &other) return *this;
+    if (other.ok())
+      Assign(other.data_);
+    else
+      Assign(other.status_);
+    return *this;
+  }
+
+  StatusOrData& operator=(StatusOrData&& other) {
+    if (this == &other) return *this;
+    if (other.ok())
+      Assign(std::move(other.data_));
+    else
+      Assign(std::move(other.status_));
+    return *this;
+  }
+
+  ~StatusOrData() {
+    if (ok()) {
+      status_.~Status();
+      data_.~T();
+    } else {
+      status_.~Status();
+    }
+  }
+
+  void Assign(const T& value) {
+    if (ok()) {
+      data_.~T();
+      MakeValue(value);
+    } else {
+      MakeValue(value);
+      status_ = OkStatus();
+    }
+  }
+
+  void Assign(T&& value) {
+    if (ok()) {
+      data_.~T();
+      MakeValue(std::move(value));
+    } else {
+      MakeValue(std::move(value));
+      status_ = OkStatus();
+    }
+  }
+
+  void Assign(const Status& status) {
+    Clear();
+    status_ = status;
+    EnsureNotOk();
+  }
+
+  void Assign(Status&& status) {
+    Clear();
+    // Note that we copy instead of moving the status here so that
+    // status.~StatusOrData() can call ok() without invoking UB.
+    status_ = status;
+    EnsureNotOk();
+  }
+
+  bool ok() const { return status_.ok(); }
+
+ protected:
+  // status_ will always be active after the constructor.
+  // We make it a union to be able to initialize exactly how we need without
+  // waste.
+  // Eg. in the copy constructor we use the default constructor of Status in
+  // the ok() path to avoid an extra Ref call.
+  union {
+    Status status_;
+  };
+
+  // data_ is active iff status_.ok()==true
+  struct Dummy {};
+  union {
+    // When T is const, we need some non-const object we can cast to void* for
+    // the placement new. dummy_ is that object.
+    Dummy dummy_;
+    T data_;
+  };
+
+  void Clear() {
+    if (ok()) data_.~T();
+  }
+
+  void EnsureOk() const {
+    if (!ok()) Helper::Crash(status_);
+  }
+
+  void EnsureNotOk() {
+    if (ok()) Helper::HandleInvalidStatusCtorArg(&status_);
+  }
+
+  // Construct the value (ie. data_) through placement new with the passed
+  // argument.
+  template <typename Arg>
+  void MakeValue(Arg&& arg) {
+    internal_statusor::PlacementNew<T>(&dummy_, std::forward<Arg>(arg));
+  }
+
+  // Construct the status (ie. status_) through placement new with the passed
+  // argument.
+  template <typename... Args>
+  void MakeStatus(Args&&... args) {
+    internal_statusor::PlacementNew<Status>(&status_,
+                                            std::forward<Args>(args)...);
+  }
+};
+
+// Helper base class to allow implicitly deleted constructors and assignment
+// operations in StatusOr.
+// TraitsBase will explicitly delete what it can't support and StatusOr will
+// inherit that behavior implicitly.
+template <bool Copy, bool Move>
+struct TraitsBase {
+  TraitsBase() = default;
+  TraitsBase(const TraitsBase&) = default;
+  TraitsBase(TraitsBase&&) = default;
+  TraitsBase& operator=(const TraitsBase&) = default;
+  TraitsBase& operator=(TraitsBase&&) = default;
+};
+
+template <>
+struct TraitsBase<false, true> {
+  TraitsBase() = default;
+  TraitsBase(const TraitsBase&) = delete;
+  TraitsBase(TraitsBase&&) = default;
+  TraitsBase& operator=(const TraitsBase&) = delete;
+  TraitsBase& operator=(TraitsBase&&) = default;
+};
+
+template <>
+struct TraitsBase<false, false> {
+  TraitsBase() = default;
+  TraitsBase(const TraitsBase&) = delete;
+  TraitsBase(TraitsBase&&) = delete;
+  TraitsBase& operator=(const TraitsBase&) = delete;
+  TraitsBase& operator=(TraitsBase&&) = delete;
+};
+
+}  // namespace internal_statusor
+
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_STATUS_STATUSOR_INTERNALS_H_
diff --git a/third_party/abseil_cpp/absl/status/statusor_test.cc b/third_party/abseil_cpp/absl/status/statusor_test.cc
new file mode 100644
index 000000000000..c2e8fb7e359e
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/statusor_test.cc
@@ -0,0 +1,1811 @@
+// Copyright 2020 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/status/statusor.h"
+
+#include <array>
+#include <initializer_list>
+#include <memory>
+#include <type_traits>
+#include <utility>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/base/casts.h"
+#include "absl/memory/memory.h"
+#include "absl/status/status.h"
+#include "absl/types/any.h"
+#include "absl/utility/utility.h"
+
+namespace {
+
+using ::testing::AllOf;
+using ::testing::AnyWith;
+using ::testing::ElementsAre;
+using ::testing::Field;
+using ::testing::Ne;
+using ::testing::Not;
+using ::testing::Pointee;
+using ::testing::VariantWith;
+
+#ifdef GTEST_HAS_STATUS_MATCHERS
+using ::testing::status::IsOk;
+using ::testing::status::IsOkAndHolds;
+#else  // GTEST_HAS_STATUS_MATCHERS
+inline const ::absl::Status& GetStatus(const ::absl::Status& status) {
+  return status;
+}
+
+template <typename T>
+inline const ::absl::Status& GetStatus(const ::absl::StatusOr<T>& status) {
+  return status.status();
+}
+
+// Monomorphic implementation of matcher IsOkAndHolds(m).  StatusOrType is a
+// reference to StatusOr<T>.
+template <typename StatusOrType>
+class IsOkAndHoldsMatcherImpl
+    : public ::testing::MatcherInterface<StatusOrType> {
+ public:
+  typedef
+      typename std::remove_reference<StatusOrType>::type::value_type value_type;
+
+  template <typename InnerMatcher>
+  explicit IsOkAndHoldsMatcherImpl(InnerMatcher&& inner_matcher)
+      : inner_matcher_(::testing::SafeMatcherCast<const value_type&>(
+            std::forward<InnerMatcher>(inner_matcher))) {}
+
+  void DescribeTo(std::ostream* os) const override {
+    *os << "is OK and has a value that ";
+    inner_matcher_.DescribeTo(os);
+  }
+
+  void DescribeNegationTo(std::ostream* os) const override {
+    *os << "isn't OK or has a value that ";
+    inner_matcher_.DescribeNegationTo(os);
+  }
+
+  bool MatchAndExplain(
+      StatusOrType actual_value,
+      ::testing::MatchResultListener* result_listener) const override {
+    if (!actual_value.ok()) {
+      *result_listener << "which has status " << actual_value.status();
+      return false;
+    }
+
+    ::testing::StringMatchResultListener inner_listener;
+    const bool matches =
+        inner_matcher_.MatchAndExplain(*actual_value, &inner_listener);
+    const std::string inner_explanation = inner_listener.str();
+    if (!inner_explanation.empty()) {
+      *result_listener << "which contains value "
+                       << ::testing::PrintToString(*actual_value) << ", "
+                       << inner_explanation;
+    }
+    return matches;
+  }
+
+ private:
+  const ::testing::Matcher<const value_type&> inner_matcher_;
+};
+
+// Implements IsOkAndHolds(m) as a polymorphic matcher.
+template <typename InnerMatcher>
+class IsOkAndHoldsMatcher {
+ public:
+  explicit IsOkAndHoldsMatcher(InnerMatcher inner_matcher)
+      : inner_matcher_(std::move(inner_matcher)) {}
+
+  // Converts this polymorphic matcher to a monomorphic matcher of the
+  // given type.  StatusOrType can be either StatusOr<T> or a
+  // reference to StatusOr<T>.
+  template <typename StatusOrType>
+  operator ::testing::Matcher<StatusOrType>() const {  // NOLINT
+    return ::testing::Matcher<StatusOrType>(
+        new IsOkAndHoldsMatcherImpl<const StatusOrType&>(inner_matcher_));
+  }
+
+ private:
+  const InnerMatcher inner_matcher_;
+};
+
+// Monomorphic implementation of matcher IsOk() for a given type T.
+// T can be Status, StatusOr<>, or a reference to either of them.
+template <typename T>
+class MonoIsOkMatcherImpl : public ::testing::MatcherInterface<T> {
+ public:
+  void DescribeTo(std::ostream* os) const override { *os << "is OK"; }
+  void DescribeNegationTo(std::ostream* os) const override {
+    *os << "is not OK";
+  }
+  bool MatchAndExplain(T actual_value,
+                       ::testing::MatchResultListener*) const override {
+    return GetStatus(actual_value).ok();
+  }
+};
+
+// Implements IsOk() as a polymorphic matcher.
+class IsOkMatcher {
+ public:
+  template <typename T>
+  operator ::testing::Matcher<T>() const {  // NOLINT
+    return ::testing::Matcher<T>(new MonoIsOkMatcherImpl<T>());
+  }
+};
+
+// Macros for testing the results of functions that return absl::Status or
+// absl::StatusOr<T> (for any type T).
+#define EXPECT_OK(expression) EXPECT_THAT(expression, IsOk())
+
+// Returns a gMock matcher that matches a StatusOr<> whose status is
+// OK and whose value matches the inner matcher.
+template <typename InnerMatcher>
+IsOkAndHoldsMatcher<typename std::decay<InnerMatcher>::type> IsOkAndHolds(
+    InnerMatcher&& inner_matcher) {
+  return IsOkAndHoldsMatcher<typename std::decay<InnerMatcher>::type>(
+      std::forward<InnerMatcher>(inner_matcher));
+}
+
+// Returns a gMock matcher that matches a Status or StatusOr<> which is OK.
+inline IsOkMatcher IsOk() { return IsOkMatcher(); }
+#endif  // GTEST_HAS_STATUS_MATCHERS
+
+struct CopyDetector {
+  CopyDetector() = default;
+  explicit CopyDetector(int xx) : x(xx) {}
+  CopyDetector(CopyDetector&& d) noexcept
+      : x(d.x), copied(false), moved(true) {}
+  CopyDetector(const CopyDetector& d) : x(d.x), copied(true), moved(false) {}
+  CopyDetector& operator=(const CopyDetector& c) {
+    x = c.x;
+    copied = true;
+    moved = false;
+    return *this;
+  }
+  CopyDetector& operator=(CopyDetector&& c) noexcept {
+    x = c.x;
+    copied = false;
+    moved = true;
+    return *this;
+  }
+  int x = 0;
+  bool copied = false;
+  bool moved = false;
+};
+
+testing::Matcher<const CopyDetector&> CopyDetectorHas(int a, bool b, bool c) {
+  return AllOf(Field(&CopyDetector::x, a), Field(&CopyDetector::moved, b),
+               Field(&CopyDetector::copied, c));
+}
+
+class Base1 {
+ public:
+  virtual ~Base1() {}
+  int pad;
+};
+
+class Base2 {
+ public:
+  virtual ~Base2() {}
+  int yetotherpad;
+};
+
+class Derived : public Base1, public Base2 {
+ public:
+  virtual ~Derived() {}
+  int evenmorepad;
+};
+
+class CopyNoAssign {
+ public:
+  explicit CopyNoAssign(int value) : foo(value) {}
+  CopyNoAssign(const CopyNoAssign& other) : foo(other.foo) {}
+  int foo;
+
+ private:
+  const CopyNoAssign& operator=(const CopyNoAssign&);
+};
+
+absl::StatusOr<std::unique_ptr<int>> ReturnUniquePtr() {
+  // Uses implicit constructor from T&&
+  return absl::make_unique<int>(0);
+}
+
+TEST(StatusOr, ElementType) {
+  static_assert(std::is_same<absl::StatusOr<int>::value_type, int>(), "");
+  static_assert(std::is_same<absl::StatusOr<char>::value_type, char>(), "");
+}
+
+TEST(StatusOr, TestMoveOnlyInitialization) {
+  absl::StatusOr<std::unique_ptr<int>> thing(ReturnUniquePtr());
+  ASSERT_TRUE(thing.ok());
+  EXPECT_EQ(0, **thing);
+  int* previous = thing->get();
+
+  thing = ReturnUniquePtr();
+  EXPECT_TRUE(thing.ok());
+  EXPECT_EQ(0, **thing);
+  EXPECT_NE(previous, thing->get());
+}
+
+TEST(StatusOr, TestMoveOnlyValueExtraction) {
+  absl::StatusOr<std::unique_ptr<int>> thing(ReturnUniquePtr());
+  ASSERT_TRUE(thing.ok());
+  std::unique_ptr<int> ptr = *std::move(thing);
+  EXPECT_EQ(0, *ptr);
+
+  thing = std::move(ptr);
+  ptr = std::move(*thing);
+  EXPECT_EQ(0, *ptr);
+}
+
+TEST(StatusOr, TestMoveOnlyInitializationFromTemporaryByValueOrDie) {
+  std::unique_ptr<int> ptr(*ReturnUniquePtr());
+  EXPECT_EQ(0, *ptr);
+}
+
+TEST(StatusOr, TestValueOrDieOverloadForConstTemporary) {
+  static_assert(
+      std::is_same<const int&&,
+                   decltype(
+                       std::declval<const absl::StatusOr<int>&&>().value())>(),
+      "value() for const temporaries should return const T&&");
+}
+
+TEST(StatusOr, TestMoveOnlyConversion) {
+  absl::StatusOr<std::unique_ptr<const int>> const_thing(ReturnUniquePtr());
+  EXPECT_TRUE(const_thing.ok());
+  EXPECT_EQ(0, **const_thing);
+
+  // Test rvalue converting assignment
+  const int* const_previous = const_thing->get();
+  const_thing = ReturnUniquePtr();
+  EXPECT_TRUE(const_thing.ok());
+  EXPECT_EQ(0, **const_thing);
+  EXPECT_NE(const_previous, const_thing->get());
+}
+
+TEST(StatusOr, TestMoveOnlyVector) {
+  // Sanity check that absl::StatusOr<MoveOnly> works in vector.
+  std::vector<absl::StatusOr<std::unique_ptr<int>>> vec;
+  vec.push_back(ReturnUniquePtr());
+  vec.resize(2);
+  auto another_vec = std::move(vec);
+  EXPECT_EQ(0, **another_vec[0]);
+  EXPECT_EQ(absl::UnknownError(""), another_vec[1].status());
+}
+
+TEST(StatusOr, TestDefaultCtor) {
+  absl::StatusOr<int> thing;
+  EXPECT_FALSE(thing.ok());
+  EXPECT_EQ(thing.status().code(), absl::StatusCode::kUnknown);
+}
+
+TEST(StatusOr, StatusCtorForwards) {
+  absl::Status status(absl::StatusCode::kInternal, "Some error");
+
+  EXPECT_EQ(absl::StatusOr<int>(status).status().message(), "Some error");
+  EXPECT_EQ(status.message(), "Some error");
+
+  EXPECT_EQ(absl::StatusOr<int>(std::move(status)).status().message(),
+            "Some error");
+  EXPECT_NE(status.message(), "Some error");
+}
+
+// Define `EXPECT_DEATH_OR_THROW` to test the behavior of `StatusOr::value`,
+// which either throws `BadStatusOrAccess` or `LOG(FATAL)` based on whether
+// exceptions are enabled.
+#ifdef ABSL_HAVE_EXCEPTIONS
+#define EXPECT_DEATH_OR_THROW(statement, status_)    \
+  EXPECT_THROW(                                      \
+      {                                              \
+        try {                                        \
+          statement;                                 \
+        } catch (const absl::BadStatusOrAccess& e) { \
+          EXPECT_EQ(e.status(), status_);            \
+          throw;                                     \
+        }                                            \
+      },                                             \
+      absl::BadStatusOrAccess);
+#else  // ABSL_HAVE_EXCEPTIONS
+#define EXPECT_DEATH_OR_THROW(statement, status) \
+  EXPECT_DEATH_IF_SUPPORTED(statement, status.ToString());
+#endif  // ABSL_HAVE_EXCEPTIONS
+
+TEST(StatusOrDeathTest, TestDefaultCtorValue) {
+  absl::StatusOr<int> thing;
+  EXPECT_DEATH_OR_THROW(thing.value(), absl::UnknownError(""));
+  const absl::StatusOr<int> thing2;
+  EXPECT_DEATH_OR_THROW(thing2.value(), absl::UnknownError(""));
+}
+
+TEST(StatusOrDeathTest, TestValueNotOk) {
+  absl::StatusOr<int> thing(absl::CancelledError());
+  EXPECT_DEATH_OR_THROW(thing.value(), absl::CancelledError());
+}
+
+TEST(StatusOrDeathTest, TestValueNotOkConst) {
+  const absl::StatusOr<int> thing(absl::UnknownError(""));
+  EXPECT_DEATH_OR_THROW(thing.value(), absl::UnknownError(""));
+}
+
+TEST(StatusOrDeathTest, TestPointerDefaultCtorValue) {
+  absl::StatusOr<int*> thing;
+  EXPECT_DEATH_OR_THROW(thing.value(), absl::UnknownError(""));
+}
+
+TEST(StatusOrDeathTest, TestPointerValueNotOk) {
+  absl::StatusOr<int*> thing(absl::CancelledError());
+  EXPECT_DEATH_OR_THROW(thing.value(), absl::CancelledError());
+}
+
+TEST(StatusOrDeathTest, TestPointerValueNotOkConst) {
+  const absl::StatusOr<int*> thing(absl::CancelledError());
+  EXPECT_DEATH_OR_THROW(thing.value(), absl::CancelledError());
+}
+
+#if GTEST_HAS_DEATH_TEST
+TEST(StatusOrDeathTest, TestStatusCtorStatusOk) {
+  EXPECT_DEBUG_DEATH(
+      {
+        // This will DCHECK
+        absl::StatusOr<int> thing(absl::OkStatus());
+        // In optimized mode, we are actually going to get error::INTERNAL for
+        // status here, rather than crashing, so check that.
+        EXPECT_FALSE(thing.ok());
+        EXPECT_EQ(thing.status().code(), absl::StatusCode::kInternal);
+      },
+      "An OK status is not a valid constructor argument");
+}
+
+TEST(StatusOrDeathTest, TestPointerStatusCtorStatusOk) {
+  EXPECT_DEBUG_DEATH(
+      {
+        absl::StatusOr<int*> thing(absl::OkStatus());
+        // In optimized mode, we are actually going to get error::INTERNAL for
+        // status here, rather than crashing, so check that.
+        EXPECT_FALSE(thing.ok());
+        EXPECT_EQ(thing.status().code(), absl::StatusCode::kInternal);
+      },
+      "An OK status is not a valid constructor argument");
+}
+#endif
+
+TEST(StatusOr, ValueAccessor) {
+  const int kIntValue = 110;
+  {
+    absl::StatusOr<int> status_or(kIntValue);
+    EXPECT_EQ(kIntValue, status_or.value());
+    EXPECT_EQ(kIntValue, std::move(status_or).value());
+  }
+  {
+    absl::StatusOr<CopyDetector> status_or(kIntValue);
+    EXPECT_THAT(status_or,
+                IsOkAndHolds(CopyDetectorHas(kIntValue, false, false)));
+    CopyDetector copy_detector = status_or.value();
+    EXPECT_THAT(copy_detector, CopyDetectorHas(kIntValue, false, true));
+    copy_detector = std::move(status_or).value();
+    EXPECT_THAT(copy_detector, CopyDetectorHas(kIntValue, true, false));
+  }
+}
+
+TEST(StatusOr, BadValueAccess) {
+  const absl::Status kError = absl::CancelledError("message");
+  absl::StatusOr<int> status_or(kError);
+  EXPECT_DEATH_OR_THROW(status_or.value(), kError);
+}
+
+TEST(StatusOr, TestStatusCtor) {
+  absl::StatusOr<int> thing(absl::CancelledError());
+  EXPECT_FALSE(thing.ok());
+  EXPECT_EQ(thing.status().code(), absl::StatusCode::kCancelled);
+}
+
+
+
+TEST(StatusOr, TestValueCtor) {
+  const int kI = 4;
+  const absl::StatusOr<int> thing(kI);
+  EXPECT_TRUE(thing.ok());
+  EXPECT_EQ(kI, *thing);
+}
+
+struct Foo {
+  const int x;
+  explicit Foo(int y) : x(y) {}
+};
+
+TEST(StatusOr, InPlaceConstruction) {
+  EXPECT_THAT(absl::StatusOr<Foo>(absl::in_place, 10),
+              IsOkAndHolds(Field(&Foo::x, 10)));
+}
+
+struct InPlaceHelper {
+  InPlaceHelper(std::initializer_list<int> xs, std::unique_ptr<int> yy)
+      : x(xs), y(std::move(yy)) {}
+  const std::vector<int> x;
+  std::unique_ptr<int> y;
+};
+
+TEST(StatusOr, InPlaceInitListConstruction) {
+  absl::StatusOr<InPlaceHelper> status_or(absl::in_place, {10, 11, 12},
+                                          absl::make_unique<int>(13));
+  EXPECT_THAT(status_or, IsOkAndHolds(AllOf(
+                             Field(&InPlaceHelper::x, ElementsAre(10, 11, 12)),
+                             Field(&InPlaceHelper::y, Pointee(13)))));
+}
+
+TEST(StatusOr, Emplace) {
+  absl::StatusOr<Foo> status_or_foo(10);
+  status_or_foo.emplace(20);
+  EXPECT_THAT(status_or_foo, IsOkAndHolds(Field(&Foo::x, 20)));
+  status_or_foo = absl::InvalidArgumentError("msg");
+  EXPECT_FALSE(status_or_foo.ok());
+  EXPECT_EQ(status_or_foo.status().code(), absl::StatusCode::kInvalidArgument);
+  EXPECT_EQ(status_or_foo.status().message(), "msg");
+  status_or_foo.emplace(20);
+  EXPECT_THAT(status_or_foo, IsOkAndHolds(Field(&Foo::x, 20)));
+}
+
+TEST(StatusOr, EmplaceInitializerList) {
+  absl::StatusOr<InPlaceHelper> status_or(absl::in_place, {10, 11, 12},
+                                          absl::make_unique<int>(13));
+  status_or.emplace({1, 2, 3}, absl::make_unique<int>(4));
+  EXPECT_THAT(status_or,
+              IsOkAndHolds(AllOf(Field(&InPlaceHelper::x, ElementsAre(1, 2, 3)),
+                                 Field(&InPlaceHelper::y, Pointee(4)))));
+  status_or = absl::InvalidArgumentError("msg");
+  EXPECT_FALSE(status_or.ok());
+  EXPECT_EQ(status_or.status().code(), absl::StatusCode::kInvalidArgument);
+  EXPECT_EQ(status_or.status().message(), "msg");
+  status_or.emplace({1, 2, 3}, absl::make_unique<int>(4));
+  EXPECT_THAT(status_or,
+              IsOkAndHolds(AllOf(Field(&InPlaceHelper::x, ElementsAre(1, 2, 3)),
+                                 Field(&InPlaceHelper::y, Pointee(4)))));
+}
+
+TEST(StatusOr, TestCopyCtorStatusOk) {
+  const int kI = 4;
+  const absl::StatusOr<int> original(kI);
+  const absl::StatusOr<int> copy(original);
+  EXPECT_OK(copy.status());
+  EXPECT_EQ(*original, *copy);
+}
+
+TEST(StatusOr, TestCopyCtorStatusNotOk) {
+  absl::StatusOr<int> original(absl::CancelledError());
+  absl::StatusOr<int> copy(original);
+  EXPECT_EQ(copy.status().code(), absl::StatusCode::kCancelled);
+}
+
+TEST(StatusOr, TestCopyCtorNonAssignable) {
+  const int kI = 4;
+  CopyNoAssign value(kI);
+  absl::StatusOr<CopyNoAssign> original(value);
+  absl::StatusOr<CopyNoAssign> copy(original);
+  EXPECT_OK(copy.status());
+  EXPECT_EQ(original->foo, copy->foo);
+}
+
+TEST(StatusOr, TestCopyCtorStatusOKConverting) {
+  const int kI = 4;
+  absl::StatusOr<int> original(kI);
+  absl::StatusOr<double> copy(original);
+  EXPECT_OK(copy.status());
+  EXPECT_DOUBLE_EQ(*original, *copy);
+}
+
+TEST(StatusOr, TestCopyCtorStatusNotOkConverting) {
+  absl::StatusOr<int> original(absl::CancelledError());
+  absl::StatusOr<double> copy(original);
+  EXPECT_EQ(copy.status(), original.status());
+}
+
+TEST(StatusOr, TestAssignmentStatusOk) {
+  // Copy assignmment
+  {
+    const auto p = std::make_shared<int>(17);
+    absl::StatusOr<std::shared_ptr<int>> source(p);
+
+    absl::StatusOr<std::shared_ptr<int>> target;
+    target = source;
+
+    ASSERT_TRUE(target.ok());
+    EXPECT_OK(target.status());
+    EXPECT_EQ(p, *target);
+
+    ASSERT_TRUE(source.ok());
+    EXPECT_OK(source.status());
+    EXPECT_EQ(p, *source);
+  }
+
+  // Move asssignment
+  {
+    const auto p = std::make_shared<int>(17);
+    absl::StatusOr<std::shared_ptr<int>> source(p);
+
+    absl::StatusOr<std::shared_ptr<int>> target;
+    target = std::move(source);
+
+    ASSERT_TRUE(target.ok());
+    EXPECT_OK(target.status());
+    EXPECT_EQ(p, *target);
+
+    ASSERT_TRUE(source.ok());
+    EXPECT_OK(source.status());
+    EXPECT_EQ(nullptr, *source);
+  }
+}
+
+TEST(StatusOr, TestAssignmentStatusNotOk) {
+  // Copy assignment
+  {
+    const absl::Status expected = absl::CancelledError();
+    absl::StatusOr<int> source(expected);
+
+    absl::StatusOr<int> target;
+    target = source;
+
+    EXPECT_FALSE(target.ok());
+    EXPECT_EQ(expected, target.status());
+
+    EXPECT_FALSE(source.ok());
+    EXPECT_EQ(expected, source.status());
+  }
+
+  // Move assignment
+  {
+    const absl::Status expected = absl::CancelledError();
+    absl::StatusOr<int> source(expected);
+
+    absl::StatusOr<int> target;
+    target = std::move(source);
+
+    EXPECT_FALSE(target.ok());
+    EXPECT_EQ(expected, target.status());
+
+    EXPECT_FALSE(source.ok());
+    EXPECT_EQ(source.status().code(), absl::StatusCode::kInternal);
+  }
+}
+
+TEST(StatusOr, TestAssignmentStatusOKConverting) {
+  // Copy assignment
+  {
+    const int kI = 4;
+    absl::StatusOr<int> source(kI);
+
+    absl::StatusOr<double> target;
+    target = source;
+
+    ASSERT_TRUE(target.ok());
+    EXPECT_OK(target.status());
+    EXPECT_DOUBLE_EQ(kI, *target);
+
+    ASSERT_TRUE(source.ok());
+    EXPECT_OK(source.status());
+    EXPECT_DOUBLE_EQ(kI, *source);
+  }
+
+  // Move assignment
+  {
+    const auto p = new int(17);
+    absl::StatusOr<std::unique_ptr<int>> source(absl::WrapUnique(p));
+
+    absl::StatusOr<std::shared_ptr<int>> target;
+    target = std::move(source);
+
+    ASSERT_TRUE(target.ok());
+    EXPECT_OK(target.status());
+    EXPECT_EQ(p, target->get());
+
+    ASSERT_TRUE(source.ok());
+    EXPECT_OK(source.status());
+    EXPECT_EQ(nullptr, source->get());
+  }
+}
+
+struct A {
+  int x;
+};
+
+struct ImplicitConstructibleFromA {
+  int x;
+  bool moved;
+  ImplicitConstructibleFromA(const A& a)  // NOLINT
+      : x(a.x), moved(false) {}
+  ImplicitConstructibleFromA(A&& a)  // NOLINT
+      : x(a.x), moved(true) {}
+};
+
+TEST(StatusOr, ImplicitConvertingConstructor) {
+  EXPECT_THAT(
+      absl::implicit_cast<absl::StatusOr<ImplicitConstructibleFromA>>(
+          absl::StatusOr<A>(A{11})),
+      IsOkAndHolds(AllOf(Field(&ImplicitConstructibleFromA::x, 11),
+                         Field(&ImplicitConstructibleFromA::moved, true))));
+  absl::StatusOr<A> a(A{12});
+  EXPECT_THAT(
+      absl::implicit_cast<absl::StatusOr<ImplicitConstructibleFromA>>(a),
+      IsOkAndHolds(AllOf(Field(&ImplicitConstructibleFromA::x, 12),
+                         Field(&ImplicitConstructibleFromA::moved, false))));
+}
+
+struct ExplicitConstructibleFromA {
+  int x;
+  bool moved;
+  explicit ExplicitConstructibleFromA(const A& a) : x(a.x), moved(false) {}
+  explicit ExplicitConstructibleFromA(A&& a) : x(a.x), moved(true) {}
+};
+
+TEST(StatusOr, ExplicitConvertingConstructor) {
+  EXPECT_FALSE(
+      (std::is_convertible<const absl::StatusOr<A>&,
+                           absl::StatusOr<ExplicitConstructibleFromA>>::value));
+  EXPECT_FALSE(
+      (std::is_convertible<absl::StatusOr<A>&&,
+                           absl::StatusOr<ExplicitConstructibleFromA>>::value));
+  EXPECT_THAT(
+      absl::StatusOr<ExplicitConstructibleFromA>(absl::StatusOr<A>(A{11})),
+      IsOkAndHolds(AllOf(Field(&ExplicitConstructibleFromA::x, 11),
+                         Field(&ExplicitConstructibleFromA::moved, true))));
+  absl::StatusOr<A> a(A{12});
+  EXPECT_THAT(
+      absl::StatusOr<ExplicitConstructibleFromA>(a),
+      IsOkAndHolds(AllOf(Field(&ExplicitConstructibleFromA::x, 12),
+                         Field(&ExplicitConstructibleFromA::moved, false))));
+}
+
+struct ImplicitConstructibleFromBool {
+  ImplicitConstructibleFromBool(bool y) : x(y) {}  // NOLINT
+  bool x = false;
+};
+
+struct ConvertibleToBool {
+  explicit ConvertibleToBool(bool y) : x(y) {}
+  operator bool() const { return x; }  // NOLINT
+  bool x = false;
+};
+
+TEST(StatusOr, ImplicitBooleanConstructionWithImplicitCasts) {
+  EXPECT_THAT(absl::StatusOr<bool>(absl::StatusOr<ConvertibleToBool>(true)),
+              IsOkAndHolds(true));
+  EXPECT_THAT(absl::StatusOr<bool>(absl::StatusOr<ConvertibleToBool>(false)),
+              IsOkAndHolds(false));
+  EXPECT_THAT(
+      absl::implicit_cast<absl::StatusOr<ImplicitConstructibleFromBool>>(
+          absl::StatusOr<bool>(false)),
+      IsOkAndHolds(Field(&ImplicitConstructibleFromBool::x, false)));
+  EXPECT_FALSE((std::is_convertible<
+                absl::StatusOr<ConvertibleToBool>,
+                absl::StatusOr<ImplicitConstructibleFromBool>>::value));
+}
+
+TEST(StatusOr, BooleanConstructionWithImplicitCasts) {
+  EXPECT_THAT(absl::StatusOr<bool>(absl::StatusOr<ConvertibleToBool>(true)),
+              IsOkAndHolds(true));
+  EXPECT_THAT(absl::StatusOr<bool>(absl::StatusOr<ConvertibleToBool>(false)),
+              IsOkAndHolds(false));
+  EXPECT_THAT(
+      absl::StatusOr<ImplicitConstructibleFromBool>{
+          absl::StatusOr<bool>(false)},
+      IsOkAndHolds(Field(&ImplicitConstructibleFromBool::x, false)));
+  EXPECT_THAT(
+      absl::StatusOr<ImplicitConstructibleFromBool>{
+          absl::StatusOr<bool>(absl::InvalidArgumentError(""))},
+      Not(IsOk()));
+
+  EXPECT_THAT(
+      absl::StatusOr<ImplicitConstructibleFromBool>{
+          absl::StatusOr<ConvertibleToBool>(ConvertibleToBool{false})},
+      IsOkAndHolds(Field(&ImplicitConstructibleFromBool::x, false)));
+  EXPECT_THAT(
+      absl::StatusOr<ImplicitConstructibleFromBool>{
+          absl::StatusOr<ConvertibleToBool>(absl::InvalidArgumentError(""))},
+      Not(IsOk()));
+}
+
+TEST(StatusOr, ConstImplicitCast) {
+  EXPECT_THAT(absl::implicit_cast<absl::StatusOr<bool>>(
+                  absl::StatusOr<const bool>(true)),
+              IsOkAndHolds(true));
+  EXPECT_THAT(absl::implicit_cast<absl::StatusOr<bool>>(
+                  absl::StatusOr<const bool>(false)),
+              IsOkAndHolds(false));
+  EXPECT_THAT(absl::implicit_cast<absl::StatusOr<const bool>>(
+                  absl::StatusOr<bool>(true)),
+              IsOkAndHolds(true));
+  EXPECT_THAT(absl::implicit_cast<absl::StatusOr<const bool>>(
+                  absl::StatusOr<bool>(false)),
+              IsOkAndHolds(false));
+  EXPECT_THAT(absl::implicit_cast<absl::StatusOr<const std::string>>(
+                  absl::StatusOr<std::string>("foo")),
+              IsOkAndHolds("foo"));
+  EXPECT_THAT(absl::implicit_cast<absl::StatusOr<std::string>>(
+                  absl::StatusOr<const std::string>("foo")),
+              IsOkAndHolds("foo"));
+  EXPECT_THAT(
+      absl::implicit_cast<absl::StatusOr<std::shared_ptr<const std::string>>>(
+          absl::StatusOr<std::shared_ptr<std::string>>(
+              std::make_shared<std::string>("foo"))),
+      IsOkAndHolds(Pointee(std::string("foo"))));
+}
+
+TEST(StatusOr, ConstExplicitConstruction) {
+  EXPECT_THAT(absl::StatusOr<bool>(absl::StatusOr<const bool>(true)),
+              IsOkAndHolds(true));
+  EXPECT_THAT(absl::StatusOr<bool>(absl::StatusOr<const bool>(false)),
+              IsOkAndHolds(false));
+  EXPECT_THAT(absl::StatusOr<const bool>(absl::StatusOr<bool>(true)),
+              IsOkAndHolds(true));
+  EXPECT_THAT(absl::StatusOr<const bool>(absl::StatusOr<bool>(false)),
+              IsOkAndHolds(false));
+}
+
+struct ExplicitConstructibleFromInt {
+  int x;
+  explicit ExplicitConstructibleFromInt(int y) : x(y) {}
+};
+
+TEST(StatusOr, ExplicitConstruction) {
+  EXPECT_THAT(absl::StatusOr<ExplicitConstructibleFromInt>(10),
+              IsOkAndHolds(Field(&ExplicitConstructibleFromInt::x, 10)));
+}
+
+TEST(StatusOr, ImplicitConstruction) {
+  // Check implicit casting works.
+  auto status_or =
+      absl::implicit_cast<absl::StatusOr<absl::variant<int, std::string>>>(10);
+  EXPECT_THAT(status_or, IsOkAndHolds(VariantWith<int>(10)));
+}
+
+TEST(StatusOr, ImplicitConstructionFromInitliazerList) {
+  // Note: dropping the explicit std::initializer_list<int> is not supported
+  // by absl::StatusOr or absl::optional.
+  auto status_or =
+      absl::implicit_cast<absl::StatusOr<std::vector<int>>>({{10, 20, 30}});
+  EXPECT_THAT(status_or, IsOkAndHolds(ElementsAre(10, 20, 30)));
+}
+
+TEST(StatusOr, UniquePtrImplicitConstruction) {
+  auto status_or = absl::implicit_cast<absl::StatusOr<std::unique_ptr<Base1>>>(
+      absl::make_unique<Derived>());
+  EXPECT_THAT(status_or, IsOkAndHolds(Ne(nullptr)));
+}
+
+TEST(StatusOr, NestedStatusOrCopyAndMoveConstructorTests) {
+  absl::StatusOr<absl::StatusOr<CopyDetector>> status_or = CopyDetector(10);
+  absl::StatusOr<absl::StatusOr<CopyDetector>> status_error =
+      absl::InvalidArgumentError("foo");
+  EXPECT_THAT(status_or,
+              IsOkAndHolds(IsOkAndHolds(CopyDetectorHas(10, true, false))));
+  absl::StatusOr<absl::StatusOr<CopyDetector>> a = status_or;
+  EXPECT_THAT(a, IsOkAndHolds(IsOkAndHolds(CopyDetectorHas(10, false, true))));
+  absl::StatusOr<absl::StatusOr<CopyDetector>> a_err = status_error;
+  EXPECT_THAT(a_err, Not(IsOk()));
+
+  const absl::StatusOr<absl::StatusOr<CopyDetector>>& cref = status_or;
+  absl::StatusOr<absl::StatusOr<CopyDetector>> b = cref;  // NOLINT
+  EXPECT_THAT(b, IsOkAndHolds(IsOkAndHolds(CopyDetectorHas(10, false, true))));
+  const absl::StatusOr<absl::StatusOr<CopyDetector>>& cref_err = status_error;
+  absl::StatusOr<absl::StatusOr<CopyDetector>> b_err = cref_err;  // NOLINT
+  EXPECT_THAT(b_err, Not(IsOk()));
+
+  absl::StatusOr<absl::StatusOr<CopyDetector>> c = std::move(status_or);
+  EXPECT_THAT(c, IsOkAndHolds(IsOkAndHolds(CopyDetectorHas(10, true, false))));
+  absl::StatusOr<absl::StatusOr<CopyDetector>> c_err = std::move(status_error);
+  EXPECT_THAT(c_err, Not(IsOk()));
+}
+
+TEST(StatusOr, NestedStatusOrCopyAndMoveAssignment) {
+  absl::StatusOr<absl::StatusOr<CopyDetector>> status_or = CopyDetector(10);
+  absl::StatusOr<absl::StatusOr<CopyDetector>> status_error =
+      absl::InvalidArgumentError("foo");
+  absl::StatusOr<absl::StatusOr<CopyDetector>> a;
+  a = status_or;
+  EXPECT_THAT(a, IsOkAndHolds(IsOkAndHolds(CopyDetectorHas(10, false, true))));
+  a = status_error;
+  EXPECT_THAT(a, Not(IsOk()));
+
+  const absl::StatusOr<absl::StatusOr<CopyDetector>>& cref = status_or;
+  a = cref;
+  EXPECT_THAT(a, IsOkAndHolds(IsOkAndHolds(CopyDetectorHas(10, false, true))));
+  const absl::StatusOr<absl::StatusOr<CopyDetector>>& cref_err = status_error;
+  a = cref_err;
+  EXPECT_THAT(a, Not(IsOk()));
+  a = std::move(status_or);
+  EXPECT_THAT(a, IsOkAndHolds(IsOkAndHolds(CopyDetectorHas(10, true, false))));
+  a = std::move(status_error);
+  EXPECT_THAT(a, Not(IsOk()));
+}
+
+struct Copyable {
+  Copyable() {}
+  Copyable(const Copyable&) {}
+  Copyable& operator=(const Copyable&) { return *this; }
+};
+
+struct MoveOnly {
+  MoveOnly() {}
+  MoveOnly(MoveOnly&&) {}
+  MoveOnly& operator=(MoveOnly&&) { return *this; }
+};
+
+struct NonMovable {
+  NonMovable() {}
+  NonMovable(const NonMovable&) = delete;
+  NonMovable(NonMovable&&) = delete;
+  NonMovable& operator=(const NonMovable&) = delete;
+  NonMovable& operator=(NonMovable&&) = delete;
+};
+
+TEST(StatusOr, CopyAndMoveAbility) {
+  EXPECT_TRUE(std::is_copy_constructible<Copyable>::value);
+  EXPECT_TRUE(std::is_copy_assignable<Copyable>::value);
+  EXPECT_TRUE(std::is_move_constructible<Copyable>::value);
+  EXPECT_TRUE(std::is_move_assignable<Copyable>::value);
+  EXPECT_FALSE(std::is_copy_constructible<MoveOnly>::value);
+  EXPECT_FALSE(std::is_copy_assignable<MoveOnly>::value);
+  EXPECT_TRUE(std::is_move_constructible<MoveOnly>::value);
+  EXPECT_TRUE(std::is_move_assignable<MoveOnly>::value);
+  EXPECT_FALSE(std::is_copy_constructible<NonMovable>::value);
+  EXPECT_FALSE(std::is_copy_assignable<NonMovable>::value);
+  EXPECT_FALSE(std::is_move_constructible<NonMovable>::value);
+  EXPECT_FALSE(std::is_move_assignable<NonMovable>::value);
+}
+
+TEST(StatusOr, StatusOrAnyCopyAndMoveConstructorTests) {
+  absl::StatusOr<absl::any> status_or = CopyDetector(10);
+  absl::StatusOr<absl::any> status_error = absl::InvalidArgumentError("foo");
+  EXPECT_THAT(
+      status_or,
+      IsOkAndHolds(AnyWith<CopyDetector>(CopyDetectorHas(10, true, false))));
+  absl::StatusOr<absl::any> a = status_or;
+  EXPECT_THAT(
+      a, IsOkAndHolds(AnyWith<CopyDetector>(CopyDetectorHas(10, false, true))));
+  absl::StatusOr<absl::any> a_err = status_error;
+  EXPECT_THAT(a_err, Not(IsOk()));
+
+  const absl::StatusOr<absl::any>& cref = status_or;
+  // No lint for no-change copy.
+  absl::StatusOr<absl::any> b = cref;  // NOLINT
+  EXPECT_THAT(
+      b, IsOkAndHolds(AnyWith<CopyDetector>(CopyDetectorHas(10, false, true))));
+  const absl::StatusOr<absl::any>& cref_err = status_error;
+  // No lint for no-change copy.
+  absl::StatusOr<absl::any> b_err = cref_err;  // NOLINT
+  EXPECT_THAT(b_err, Not(IsOk()));
+
+  absl::StatusOr<absl::any> c = std::move(status_or);
+  EXPECT_THAT(
+      c, IsOkAndHolds(AnyWith<CopyDetector>(CopyDetectorHas(10, true, false))));
+  absl::StatusOr<absl::any> c_err = std::move(status_error);
+  EXPECT_THAT(c_err, Not(IsOk()));
+}
+
+TEST(StatusOr, StatusOrAnyCopyAndMoveAssignment) {
+  absl::StatusOr<absl::any> status_or = CopyDetector(10);
+  absl::StatusOr<absl::any> status_error = absl::InvalidArgumentError("foo");
+  absl::StatusOr<absl::any> a;
+  a = status_or;
+  EXPECT_THAT(
+      a, IsOkAndHolds(AnyWith<CopyDetector>(CopyDetectorHas(10, false, true))));
+  a = status_error;
+  EXPECT_THAT(a, Not(IsOk()));
+
+  const absl::StatusOr<absl::any>& cref = status_or;
+  a = cref;
+  EXPECT_THAT(
+      a, IsOkAndHolds(AnyWith<CopyDetector>(CopyDetectorHas(10, false, true))));
+  const absl::StatusOr<absl::any>& cref_err = status_error;
+  a = cref_err;
+  EXPECT_THAT(a, Not(IsOk()));
+  a = std::move(status_or);
+  EXPECT_THAT(
+      a, IsOkAndHolds(AnyWith<CopyDetector>(CopyDetectorHas(10, true, false))));
+  a = std::move(status_error);
+  EXPECT_THAT(a, Not(IsOk()));
+}
+
+TEST(StatusOr, StatusOrCopyAndMoveTestsConstructor) {
+  absl::StatusOr<CopyDetector> status_or(10);
+  ASSERT_THAT(status_or, IsOkAndHolds(CopyDetectorHas(10, false, false)));
+  absl::StatusOr<CopyDetector> a(status_or);
+  EXPECT_THAT(a, IsOkAndHolds(CopyDetectorHas(10, false, true)));
+  const absl::StatusOr<CopyDetector>& cref = status_or;
+  absl::StatusOr<CopyDetector> b(cref);  // NOLINT
+  EXPECT_THAT(b, IsOkAndHolds(CopyDetectorHas(10, false, true)));
+  absl::StatusOr<CopyDetector> c(std::move(status_or));
+  EXPECT_THAT(c, IsOkAndHolds(CopyDetectorHas(10, true, false)));
+}
+
+TEST(StatusOr, StatusOrCopyAndMoveTestsAssignment) {
+  absl::StatusOr<CopyDetector> status_or(10);
+  ASSERT_THAT(status_or, IsOkAndHolds(CopyDetectorHas(10, false, false)));
+  absl::StatusOr<CopyDetector> a;
+  a = status_or;
+  EXPECT_THAT(a, IsOkAndHolds(CopyDetectorHas(10, false, true)));
+  const absl::StatusOr<CopyDetector>& cref = status_or;
+  absl::StatusOr<CopyDetector> b;
+  b = cref;
+  EXPECT_THAT(b, IsOkAndHolds(CopyDetectorHas(10, false, true)));
+  absl::StatusOr<CopyDetector> c;
+  c = std::move(status_or);
+  EXPECT_THAT(c, IsOkAndHolds(CopyDetectorHas(10, true, false)));
+}
+
+TEST(StatusOr, AbslAnyAssignment) {
+  EXPECT_FALSE((std::is_assignable<absl::StatusOr<absl::any>,
+                                   absl::StatusOr<int>>::value));
+  absl::StatusOr<absl::any> status_or;
+  status_or = absl::InvalidArgumentError("foo");
+  EXPECT_THAT(status_or, Not(IsOk()));
+}
+
+TEST(StatusOr, ImplicitAssignment) {
+  absl::StatusOr<absl::variant<int, std::string>> status_or;
+  status_or = 10;
+  EXPECT_THAT(status_or, IsOkAndHolds(VariantWith<int>(10)));
+}
+
+TEST(StatusOr, SelfDirectInitAssignment) {
+  absl::StatusOr<std::vector<int>> status_or = {{10, 20, 30}};
+  status_or = *status_or;
+  EXPECT_THAT(status_or, IsOkAndHolds(ElementsAre(10, 20, 30)));
+}
+
+TEST(StatusOr, ImplicitCastFromInitializerList) {
+  absl::StatusOr<std::vector<int>> status_or = {{10, 20, 30}};
+  EXPECT_THAT(status_or, IsOkAndHolds(ElementsAre(10, 20, 30)));
+}
+
+TEST(StatusOr, UniquePtrImplicitAssignment) {
+  absl::StatusOr<std::unique_ptr<Base1>> status_or;
+  status_or = absl::make_unique<Derived>();
+  EXPECT_THAT(status_or, IsOkAndHolds(Ne(nullptr)));
+}
+
+TEST(StatusOr, Pointer) {
+  struct A {};
+  struct B : public A {};
+  struct C : private A {};
+
+  EXPECT_TRUE((std::is_constructible<absl::StatusOr<A*>, B*>::value));
+  EXPECT_TRUE((std::is_convertible<B*, absl::StatusOr<A*>>::value));
+  EXPECT_FALSE((std::is_constructible<absl::StatusOr<A*>, C*>::value));
+  EXPECT_FALSE((std::is_convertible<C*, absl::StatusOr<A*>>::value));
+}
+
+TEST(StatusOr, TestAssignmentStatusNotOkConverting) {
+  // Copy assignment
+  {
+    const absl::Status expected = absl::CancelledError();
+    absl::StatusOr<int> source(expected);
+
+    absl::StatusOr<double> target;
+    target = source;
+
+    EXPECT_FALSE(target.ok());
+    EXPECT_EQ(expected, target.status());
+
+    EXPECT_FALSE(source.ok());
+    EXPECT_EQ(expected, source.status());
+  }
+
+  // Move assignment
+  {
+    const absl::Status expected = absl::CancelledError();
+    absl::StatusOr<int> source(expected);
+
+    absl::StatusOr<double> target;
+    target = std::move(source);
+
+    EXPECT_FALSE(target.ok());
+    EXPECT_EQ(expected, target.status());
+
+    EXPECT_FALSE(source.ok());
+    EXPECT_EQ(source.status().code(), absl::StatusCode::kInternal);
+  }
+}
+
+TEST(StatusOr, SelfAssignment) {
+  // Copy-assignment, status OK
+  {
+    // A string long enough that it's likely to defeat any inline representation
+    // optimization.
+    const std::string long_str(128, 'a');
+
+    absl::StatusOr<std::string> so = long_str;
+    so = *&so;
+
+    ASSERT_TRUE(so.ok());
+    EXPECT_OK(so.status());
+    EXPECT_EQ(long_str, *so);
+  }
+
+  // Copy-assignment, error status
+  {
+    absl::StatusOr<int> so = absl::NotFoundError("taco");
+    so = *&so;
+
+    EXPECT_FALSE(so.ok());
+    EXPECT_EQ(so.status().code(), absl::StatusCode::kNotFound);
+    EXPECT_EQ(so.status().message(), "taco");
+  }
+
+  // Move-assignment with copyable type, status OK
+  {
+    absl::StatusOr<int> so = 17;
+
+    // Fool the compiler, which otherwise complains.
+    auto& same = so;
+    so = std::move(same);
+
+    ASSERT_TRUE(so.ok());
+    EXPECT_OK(so.status());
+    EXPECT_EQ(17, *so);
+  }
+
+  // Move-assignment with copyable type, error status
+  {
+    absl::StatusOr<int> so = absl::NotFoundError("taco");
+
+    // Fool the compiler, which otherwise complains.
+    auto& same = so;
+    so = std::move(same);
+
+    EXPECT_FALSE(so.ok());
+    EXPECT_EQ(so.status().code(), absl::StatusCode::kNotFound);
+    EXPECT_EQ(so.status().message(), "taco");
+  }
+
+  // Move-assignment with non-copyable type, status OK
+  {
+    const auto raw = new int(17);
+    absl::StatusOr<std::unique_ptr<int>> so = absl::WrapUnique(raw);
+
+    // Fool the compiler, which otherwise complains.
+    auto& same = so;
+    so = std::move(same);
+
+    ASSERT_TRUE(so.ok());
+    EXPECT_OK(so.status());
+    EXPECT_EQ(raw, so->get());
+  }
+
+  // Move-assignment with non-copyable type, error status
+  {
+    absl::StatusOr<std::unique_ptr<int>> so = absl::NotFoundError("taco");
+
+    // Fool the compiler, which otherwise complains.
+    auto& same = so;
+    so = std::move(same);
+
+    EXPECT_FALSE(so.ok());
+    EXPECT_EQ(so.status().code(), absl::StatusCode::kNotFound);
+    EXPECT_EQ(so.status().message(), "taco");
+  }
+}
+
+// These types form the overload sets of the constructors and the assignment
+// operators of `MockValue`. They distinguish construction from assignment,
+// lvalue from rvalue.
+struct FromConstructibleAssignableLvalue {};
+struct FromConstructibleAssignableRvalue {};
+struct FromImplicitConstructibleOnly {};
+struct FromAssignableOnly {};
+
+// This class is for testing the forwarding value assignments of `StatusOr`.
+// `from_rvalue` indicates whether the constructor or the assignment taking
+// rvalue reference is called. `from_assignment` indicates whether any
+// assignment is called.
+struct MockValue {
+  // Constructs `MockValue` from `FromConstructibleAssignableLvalue`.
+  MockValue(const FromConstructibleAssignableLvalue&)  // NOLINT
+      : from_rvalue(false), assigned(false) {}
+  // Constructs `MockValue` from `FromConstructibleAssignableRvalue`.
+  MockValue(FromConstructibleAssignableRvalue&&)  // NOLINT
+      : from_rvalue(true), assigned(false) {}
+  // Constructs `MockValue` from `FromImplicitConstructibleOnly`.
+  // `MockValue` is not assignable from `FromImplicitConstructibleOnly`.
+  MockValue(const FromImplicitConstructibleOnly&)  // NOLINT
+      : from_rvalue(false), assigned(false) {}
+  // Assigns `FromConstructibleAssignableLvalue`.
+  MockValue& operator=(const FromConstructibleAssignableLvalue&) {
+    from_rvalue = false;
+    assigned = true;
+    return *this;
+  }
+  // Assigns `FromConstructibleAssignableRvalue` (rvalue only).
+  MockValue& operator=(FromConstructibleAssignableRvalue&&) {
+    from_rvalue = true;
+    assigned = true;
+    return *this;
+  }
+  // Assigns `FromAssignableOnly`, but not constructible from
+  // `FromAssignableOnly`.
+  MockValue& operator=(const FromAssignableOnly&) {
+    from_rvalue = false;
+    assigned = true;
+    return *this;
+  }
+  bool from_rvalue;
+  bool assigned;
+};
+
+// operator=(U&&)
+TEST(StatusOr, PerfectForwardingAssignment) {
+  // U == T
+  constexpr int kValue1 = 10, kValue2 = 20;
+  absl::StatusOr<CopyDetector> status_or;
+  CopyDetector lvalue(kValue1);
+  status_or = lvalue;
+  EXPECT_THAT(status_or, IsOkAndHolds(CopyDetectorHas(kValue1, false, true)));
+  status_or = CopyDetector(kValue2);
+  EXPECT_THAT(status_or, IsOkAndHolds(CopyDetectorHas(kValue2, true, false)));
+
+  // U != T
+  EXPECT_TRUE(
+      (std::is_assignable<absl::StatusOr<MockValue>&,
+                          const FromConstructibleAssignableLvalue&>::value));
+  EXPECT_TRUE((std::is_assignable<absl::StatusOr<MockValue>&,
+                                  FromConstructibleAssignableLvalue&&>::value));
+  EXPECT_FALSE(
+      (std::is_assignable<absl::StatusOr<MockValue>&,
+                          const FromConstructibleAssignableRvalue&>::value));
+  EXPECT_TRUE((std::is_assignable<absl::StatusOr<MockValue>&,
+                                  FromConstructibleAssignableRvalue&&>::value));
+  EXPECT_TRUE(
+      (std::is_assignable<absl::StatusOr<MockValue>&,
+                          const FromImplicitConstructibleOnly&>::value));
+  EXPECT_FALSE((std::is_assignable<absl::StatusOr<MockValue>&,
+                                   const FromAssignableOnly&>::value));
+
+  absl::StatusOr<MockValue> from_lvalue(FromConstructibleAssignableLvalue{});
+  EXPECT_FALSE(from_lvalue->from_rvalue);
+  EXPECT_FALSE(from_lvalue->assigned);
+  from_lvalue = FromConstructibleAssignableLvalue{};
+  EXPECT_FALSE(from_lvalue->from_rvalue);
+  EXPECT_TRUE(from_lvalue->assigned);
+
+  absl::StatusOr<MockValue> from_rvalue(FromConstructibleAssignableRvalue{});
+  EXPECT_TRUE(from_rvalue->from_rvalue);
+  EXPECT_FALSE(from_rvalue->assigned);
+  from_rvalue = FromConstructibleAssignableRvalue{};
+  EXPECT_TRUE(from_rvalue->from_rvalue);
+  EXPECT_TRUE(from_rvalue->assigned);
+
+  absl::StatusOr<MockValue> from_implicit_constructible(
+      FromImplicitConstructibleOnly{});
+  EXPECT_FALSE(from_implicit_constructible->from_rvalue);
+  EXPECT_FALSE(from_implicit_constructible->assigned);
+  // construct a temporary `StatusOr` object and invoke the `StatusOr` move
+  // assignment operator.
+  from_implicit_constructible = FromImplicitConstructibleOnly{};
+  EXPECT_FALSE(from_implicit_constructible->from_rvalue);
+  EXPECT_FALSE(from_implicit_constructible->assigned);
+}
+
+TEST(StatusOr, TestStatus) {
+  absl::StatusOr<int> good(4);
+  EXPECT_TRUE(good.ok());
+  absl::StatusOr<int> bad(absl::CancelledError());
+  EXPECT_FALSE(bad.ok());
+  EXPECT_EQ(bad.status().code(), absl::StatusCode::kCancelled);
+}
+
+TEST(StatusOr, OperatorStarRefQualifiers) {
+  static_assert(
+      std::is_same<const int&,
+                   decltype(*std::declval<const absl::StatusOr<int>&>())>(),
+      "Unexpected ref-qualifiers");
+  static_assert(
+      std::is_same<int&, decltype(*std::declval<absl::StatusOr<int>&>())>(),
+      "Unexpected ref-qualifiers");
+  static_assert(
+      std::is_same<const int&&,
+                   decltype(*std::declval<const absl::StatusOr<int>&&>())>(),
+      "Unexpected ref-qualifiers");
+  static_assert(
+      std::is_same<int&&, decltype(*std::declval<absl::StatusOr<int>&&>())>(),
+      "Unexpected ref-qualifiers");
+}
+
+TEST(StatusOr, OperatorStar) {
+  const absl::StatusOr<std::string> const_lvalue("hello");
+  EXPECT_EQ("hello", *const_lvalue);
+
+  absl::StatusOr<std::string> lvalue("hello");
+  EXPECT_EQ("hello", *lvalue);
+
+  // Note: Recall that std::move() is equivalent to a static_cast to an rvalue
+  // reference type.
+  const absl::StatusOr<std::string> const_rvalue("hello");
+  EXPECT_EQ("hello", *std::move(const_rvalue));  // NOLINT
+
+  absl::StatusOr<std::string> rvalue("hello");
+  EXPECT_EQ("hello", *std::move(rvalue));
+}
+
+TEST(StatusOr, OperatorArrowQualifiers) {
+  static_assert(
+      std::is_same<
+          const int*,
+          decltype(std::declval<const absl::StatusOr<int>&>().operator->())>(),
+      "Unexpected qualifiers");
+  static_assert(
+      std::is_same<
+          int*, decltype(std::declval<absl::StatusOr<int>&>().operator->())>(),
+      "Unexpected qualifiers");
+  static_assert(
+      std::is_same<
+          const int*,
+          decltype(std::declval<const absl::StatusOr<int>&&>().operator->())>(),
+      "Unexpected qualifiers");
+  static_assert(
+      std::is_same<
+          int*, decltype(std::declval<absl::StatusOr<int>&&>().operator->())>(),
+      "Unexpected qualifiers");
+}
+
+TEST(StatusOr, OperatorArrow) {
+  const absl::StatusOr<std::string> const_lvalue("hello");
+  EXPECT_EQ(std::string("hello"), const_lvalue->c_str());
+
+  absl::StatusOr<std::string> lvalue("hello");
+  EXPECT_EQ(std::string("hello"), lvalue->c_str());
+}
+
+TEST(StatusOr, RValueStatus) {
+  absl::StatusOr<int> so(absl::NotFoundError("taco"));
+  const absl::Status s = std::move(so).status();
+
+  EXPECT_EQ(s.code(), absl::StatusCode::kNotFound);
+  EXPECT_EQ(s.message(), "taco");
+
+  // Check that !ok() still implies !status().ok(), even after moving out of the
+  // object. See the note on the rvalue ref-qualified status method.
+  EXPECT_FALSE(so.ok());  // NOLINT
+  EXPECT_FALSE(so.status().ok());
+  EXPECT_EQ(so.status().code(), absl::StatusCode::kInternal);
+  EXPECT_EQ(so.status().message(), "Status accessed after move.");
+}
+
+TEST(StatusOr, TestValue) {
+  const int kI = 4;
+  absl::StatusOr<int> thing(kI);
+  EXPECT_EQ(kI, *thing);
+}
+
+TEST(StatusOr, TestValueConst) {
+  const int kI = 4;
+  const absl::StatusOr<int> thing(kI);
+  EXPECT_EQ(kI, *thing);
+}
+
+TEST(StatusOr, TestPointerDefaultCtor) {
+  absl::StatusOr<int*> thing;
+  EXPECT_FALSE(thing.ok());
+  EXPECT_EQ(thing.status().code(), absl::StatusCode::kUnknown);
+}
+
+
+
+TEST(StatusOr, TestPointerStatusCtor) {
+  absl::StatusOr<int*> thing(absl::CancelledError());
+  EXPECT_FALSE(thing.ok());
+  EXPECT_EQ(thing.status().code(), absl::StatusCode::kCancelled);
+}
+
+TEST(StatusOr, TestPointerValueCtor) {
+  const int kI = 4;
+
+  // Construction from a non-null pointer
+  {
+    absl::StatusOr<const int*> so(&kI);
+    EXPECT_TRUE(so.ok());
+    EXPECT_OK(so.status());
+    EXPECT_EQ(&kI, *so);
+  }
+
+  // Construction from a null pointer constant
+  {
+    absl::StatusOr<const int*> so(nullptr);
+    EXPECT_TRUE(so.ok());
+    EXPECT_OK(so.status());
+    EXPECT_EQ(nullptr, *so);
+  }
+
+  // Construction from a non-literal null pointer
+  {
+    const int* const p = nullptr;
+
+    absl::StatusOr<const int*> so(p);
+    EXPECT_TRUE(so.ok());
+    EXPECT_OK(so.status());
+    EXPECT_EQ(nullptr, *so);
+  }
+}
+
+TEST(StatusOr, TestPointerCopyCtorStatusOk) {
+  const int kI = 0;
+  absl::StatusOr<const int*> original(&kI);
+  absl::StatusOr<const int*> copy(original);
+  EXPECT_OK(copy.status());
+  EXPECT_EQ(*original, *copy);
+}
+
+TEST(StatusOr, TestPointerCopyCtorStatusNotOk) {
+  absl::StatusOr<int*> original(absl::CancelledError());
+  absl::StatusOr<int*> copy(original);
+  EXPECT_EQ(copy.status().code(), absl::StatusCode::kCancelled);
+}
+
+TEST(StatusOr, TestPointerCopyCtorStatusOKConverting) {
+  Derived derived;
+  absl::StatusOr<Derived*> original(&derived);
+  absl::StatusOr<Base2*> copy(original);
+  EXPECT_OK(copy.status());
+  EXPECT_EQ(static_cast<const Base2*>(*original), *copy);
+}
+
+TEST(StatusOr, TestPointerCopyCtorStatusNotOkConverting) {
+  absl::StatusOr<Derived*> original(absl::CancelledError());
+  absl::StatusOr<Base2*> copy(original);
+  EXPECT_EQ(copy.status().code(), absl::StatusCode::kCancelled);
+}
+
+TEST(StatusOr, TestPointerAssignmentStatusOk) {
+  const int kI = 0;
+  absl::StatusOr<const int*> source(&kI);
+  absl::StatusOr<const int*> target;
+  target = source;
+  EXPECT_OK(target.status());
+  EXPECT_EQ(*source, *target);
+}
+
+TEST(StatusOr, TestPointerAssignmentStatusNotOk) {
+  absl::StatusOr<int*> source(absl::CancelledError());
+  absl::StatusOr<int*> target;
+  target = source;
+  EXPECT_EQ(target.status().code(), absl::StatusCode::kCancelled);
+}
+
+TEST(StatusOr, TestPointerAssignmentStatusOKConverting) {
+  Derived derived;
+  absl::StatusOr<Derived*> source(&derived);
+  absl::StatusOr<Base2*> target;
+  target = source;
+  EXPECT_OK(target.status());
+  EXPECT_EQ(static_cast<const Base2*>(*source), *target);
+}
+
+TEST(StatusOr, TestPointerAssignmentStatusNotOkConverting) {
+  absl::StatusOr<Derived*> source(absl::CancelledError());
+  absl::StatusOr<Base2*> target;
+  target = source;
+  EXPECT_EQ(target.status(), source.status());
+}
+
+TEST(StatusOr, TestPointerStatus) {
+  const int kI = 0;
+  absl::StatusOr<const int*> good(&kI);
+  EXPECT_TRUE(good.ok());
+  absl::StatusOr<const int*> bad(absl::CancelledError());
+  EXPECT_EQ(bad.status().code(), absl::StatusCode::kCancelled);
+}
+
+TEST(StatusOr, TestPointerValue) {
+  const int kI = 0;
+  absl::StatusOr<const int*> thing(&kI);
+  EXPECT_EQ(&kI, *thing);
+}
+
+TEST(StatusOr, TestPointerValueConst) {
+  const int kI = 0;
+  const absl::StatusOr<const int*> thing(&kI);
+  EXPECT_EQ(&kI, *thing);
+}
+
+TEST(StatusOr, StatusOrVectorOfUniquePointerCanReserveAndResize) {
+  using EvilType = std::vector<std::unique_ptr<int>>;
+  static_assert(std::is_copy_constructible<EvilType>::value, "");
+  std::vector<::absl::StatusOr<EvilType>> v(5);
+  v.reserve(v.capacity() + 10);
+  v.resize(v.capacity() + 10);
+}
+
+TEST(StatusOr, ConstPayload) {
+  // A reduced version of a problematic type found in the wild. All of the
+  // operations below should compile.
+  absl::StatusOr<const int> a;
+
+  // Copy-construction
+  absl::StatusOr<const int> b(a);
+
+  // Copy-assignment
+  EXPECT_FALSE(std::is_copy_assignable<absl::StatusOr<const int>>::value);
+
+  // Move-construction
+  absl::StatusOr<const int> c(std::move(a));
+
+  // Move-assignment
+  EXPECT_FALSE(std::is_move_assignable<absl::StatusOr<const int>>::value);
+}
+
+TEST(StatusOr, MapToStatusOrUniquePtr) {
+  // A reduced version of a problematic type found in the wild. All of the
+  // operations below should compile.
+  using MapType = std::map<std::string, absl::StatusOr<std::unique_ptr<int>>>;
+
+  MapType a;
+
+  // Move-construction
+  MapType b(std::move(a));
+
+  // Move-assignment
+  a = std::move(b);
+}
+
+TEST(StatusOr, ValueOrOk) {
+  const absl::StatusOr<int> status_or = 0;
+  EXPECT_EQ(status_or.value_or(-1), 0);
+}
+
+TEST(StatusOr, ValueOrDefault) {
+  const absl::StatusOr<int> status_or = absl::CancelledError();
+  EXPECT_EQ(status_or.value_or(-1), -1);
+}
+
+TEST(StatusOr, MoveOnlyValueOrOk) {
+  EXPECT_THAT(absl::StatusOr<std::unique_ptr<int>>(absl::make_unique<int>(0))
+                  .value_or(absl::make_unique<int>(-1)),
+              Pointee(0));
+}
+
+TEST(StatusOr, MoveOnlyValueOrDefault) {
+  EXPECT_THAT(absl::StatusOr<std::unique_ptr<int>>(absl::CancelledError())
+                  .value_or(absl::make_unique<int>(-1)),
+              Pointee(-1));
+}
+
+static absl::StatusOr<int> MakeStatus() { return 100; }
+
+TEST(StatusOr, TestIgnoreError) { MakeStatus().IgnoreError(); }
+
+TEST(StatusOr, EqualityOperator) {
+  constexpr int kNumCases = 4;
+  std::array<absl::StatusOr<int>, kNumCases> group1 = {
+      absl::StatusOr<int>(1), absl::StatusOr<int>(2),
+      absl::StatusOr<int>(absl::InvalidArgumentError("msg")),
+      absl::StatusOr<int>(absl::InternalError("msg"))};
+  std::array<absl::StatusOr<int>, kNumCases> group2 = {
+      absl::StatusOr<int>(1), absl::StatusOr<int>(2),
+      absl::StatusOr<int>(absl::InvalidArgumentError("msg")),
+      absl::StatusOr<int>(absl::InternalError("msg"))};
+  for (int i = 0; i < kNumCases; ++i) {
+    for (int j = 0; j < kNumCases; ++j) {
+      if (i == j) {
+        EXPECT_TRUE(group1[i] == group2[j]);
+        EXPECT_FALSE(group1[i] != group2[j]);
+      } else {
+        EXPECT_FALSE(group1[i] == group2[j]);
+        EXPECT_TRUE(group1[i] != group2[j]);
+      }
+    }
+  }
+}
+
+struct MyType {
+  bool operator==(const MyType&) const { return true; }
+};
+
+enum class ConvTraits { kNone = 0, kImplicit = 1, kExplicit = 2 };
+
+// This class has conversion operator to `StatusOr<T>` based on value of
+// `conv_traits`.
+template <typename T, ConvTraits conv_traits = ConvTraits::kNone>
+struct StatusOrConversionBase {};
+
+template <typename T>
+struct StatusOrConversionBase<T, ConvTraits::kImplicit> {
+  operator absl::StatusOr<T>() const& {  // NOLINT
+    return absl::InvalidArgumentError("conversion to absl::StatusOr");
+  }
+  operator absl::StatusOr<T>() && {  // NOLINT
+    return absl::InvalidArgumentError("conversion to absl::StatusOr");
+  }
+};
+
+template <typename T>
+struct StatusOrConversionBase<T, ConvTraits::kExplicit> {
+  explicit operator absl::StatusOr<T>() const& {
+    return absl::InvalidArgumentError("conversion to absl::StatusOr");
+  }
+  explicit operator absl::StatusOr<T>() && {
+    return absl::InvalidArgumentError("conversion to absl::StatusOr");
+  }
+};
+
+// This class has conversion operator to `T` based on the value of
+// `conv_traits`.
+template <typename T, ConvTraits conv_traits = ConvTraits::kNone>
+struct ConversionBase {};
+
+template <typename T>
+struct ConversionBase<T, ConvTraits::kImplicit> {
+  operator T() const& { return t; }         // NOLINT
+  operator T() && { return std::move(t); }  // NOLINT
+  T t;
+};
+
+template <typename T>
+struct ConversionBase<T, ConvTraits::kExplicit> {
+  explicit operator T() const& { return t; }
+  explicit operator T() && { return std::move(t); }
+  T t;
+};
+
+// This class has conversion operator to `absl::Status` based on the value of
+// `conv_traits`.
+template <ConvTraits conv_traits = ConvTraits::kNone>
+struct StatusConversionBase {};
+
+template <>
+struct StatusConversionBase<ConvTraits::kImplicit> {
+  operator absl::Status() const& {  // NOLINT
+    return absl::InternalError("conversion to Status");
+  }
+  operator absl::Status() && {  // NOLINT
+    return absl::InternalError("conversion to Status");
+  }
+};
+
+template <>
+struct StatusConversionBase<ConvTraits::kExplicit> {
+  explicit operator absl::Status() const& {  // NOLINT
+    return absl::InternalError("conversion to Status");
+  }
+  explicit operator absl::Status() && {  // NOLINT
+    return absl::InternalError("conversion to Status");
+  }
+};
+
+static constexpr int kConvToStatus = 1;
+static constexpr int kConvToStatusOr = 2;
+static constexpr int kConvToT = 4;
+static constexpr int kConvExplicit = 8;
+
+constexpr ConvTraits GetConvTraits(int bit, int config) {
+  return (config & bit) == 0
+             ? ConvTraits::kNone
+             : ((config & kConvExplicit) == 0 ? ConvTraits::kImplicit
+                                              : ConvTraits::kExplicit);
+}
+
+// This class conditionally has conversion operator to `absl::Status`, `T`,
+// `StatusOr<T>`, based on values of the template parameters.
+template <typename T, int config>
+struct CustomType
+    : StatusOrConversionBase<T, GetConvTraits(kConvToStatusOr, config)>,
+      ConversionBase<T, GetConvTraits(kConvToT, config)>,
+      StatusConversionBase<GetConvTraits(kConvToStatus, config)> {};
+
+struct ConvertibleToAnyStatusOr {
+  template <typename T>
+  operator absl::StatusOr<T>() const {  // NOLINT
+    return absl::InvalidArgumentError("Conversion to absl::StatusOr");
+  }
+};
+
+// Test the rank of overload resolution for `StatusOr<T>` constructor and
+// assignment, from highest to lowest:
+// 1. T/Status
+// 2. U that has conversion operator to absl::StatusOr<T>
+// 3. U that is convertible to Status
+// 4. U that is convertible to T
+TEST(StatusOr, ConstructionFromT) {
+  // Construct absl::StatusOr<T> from T when T is convertible to
+  // absl::StatusOr<T>
+  {
+    ConvertibleToAnyStatusOr v;
+    absl::StatusOr<ConvertibleToAnyStatusOr> statusor(v);
+    EXPECT_TRUE(statusor.ok());
+  }
+  {
+    ConvertibleToAnyStatusOr v;
+    absl::StatusOr<ConvertibleToAnyStatusOr> statusor = v;
+    EXPECT_TRUE(statusor.ok());
+  }
+  // Construct absl::StatusOr<T> from T when T is explicitly convertible to
+  // Status
+  {
+    CustomType<MyType, kConvToStatus | kConvExplicit> v;
+    absl::StatusOr<CustomType<MyType, kConvToStatus | kConvExplicit>> statusor(
+        v);
+    EXPECT_TRUE(statusor.ok());
+  }
+  {
+    CustomType<MyType, kConvToStatus | kConvExplicit> v;
+    absl::StatusOr<CustomType<MyType, kConvToStatus | kConvExplicit>> statusor =
+        v;
+    EXPECT_TRUE(statusor.ok());
+  }
+}
+
+// Construct absl::StatusOr<T> from U when U is explicitly convertible to T
+TEST(StatusOr, ConstructionFromTypeConvertibleToT) {
+  {
+    CustomType<MyType, kConvToT | kConvExplicit> v;
+    absl::StatusOr<MyType> statusor(v);
+    EXPECT_TRUE(statusor.ok());
+  }
+  {
+    CustomType<MyType, kConvToT> v;
+    absl::StatusOr<MyType> statusor = v;
+    EXPECT_TRUE(statusor.ok());
+  }
+}
+
+// Construct absl::StatusOr<T> from U when U has explicit conversion operator to
+// absl::StatusOr<T>
+TEST(StatusOr, ConstructionFromTypeWithConversionOperatorToStatusOrT) {
+  {
+    CustomType<MyType, kConvToStatusOr | kConvExplicit> v;
+    absl::StatusOr<MyType> statusor(v);
+    EXPECT_EQ(statusor, v.operator absl::StatusOr<MyType>());
+  }
+  {
+    CustomType<MyType, kConvToT | kConvToStatusOr | kConvExplicit> v;
+    absl::StatusOr<MyType> statusor(v);
+    EXPECT_EQ(statusor, v.operator absl::StatusOr<MyType>());
+  }
+  {
+    CustomType<MyType, kConvToStatusOr | kConvToStatus | kConvExplicit> v;
+    absl::StatusOr<MyType> statusor(v);
+    EXPECT_EQ(statusor, v.operator absl::StatusOr<MyType>());
+  }
+  {
+    CustomType<MyType,
+               kConvToT | kConvToStatusOr | kConvToStatus | kConvExplicit>
+        v;
+    absl::StatusOr<MyType> statusor(v);
+    EXPECT_EQ(statusor, v.operator absl::StatusOr<MyType>());
+  }
+  {
+    CustomType<MyType, kConvToStatusOr> v;
+    absl::StatusOr<MyType> statusor = v;
+    EXPECT_EQ(statusor, v.operator absl::StatusOr<MyType>());
+  }
+  {
+    CustomType<MyType, kConvToT | kConvToStatusOr> v;
+    absl::StatusOr<MyType> statusor = v;
+    EXPECT_EQ(statusor, v.operator absl::StatusOr<MyType>());
+  }
+  {
+    CustomType<MyType, kConvToStatusOr | kConvToStatus> v;
+    absl::StatusOr<MyType> statusor = v;
+    EXPECT_EQ(statusor, v.operator absl::StatusOr<MyType>());
+  }
+  {
+    CustomType<MyType, kConvToT | kConvToStatusOr | kConvToStatus> v;
+    absl::StatusOr<MyType> statusor = v;
+    EXPECT_EQ(statusor, v.operator absl::StatusOr<MyType>());
+  }
+}
+
+TEST(StatusOr, ConstructionFromTypeConvertibleToStatus) {
+  // Construction fails because conversion to `Status` is explicit.
+  {
+    CustomType<MyType, kConvToStatus | kConvExplicit> v;
+    absl::StatusOr<MyType> statusor(v);
+    EXPECT_FALSE(statusor.ok());
+    EXPECT_EQ(statusor.status(), static_cast<absl::Status>(v));
+  }
+  {
+    CustomType<MyType, kConvToT | kConvToStatus | kConvExplicit> v;
+    absl::StatusOr<MyType> statusor(v);
+    EXPECT_FALSE(statusor.ok());
+    EXPECT_EQ(statusor.status(), static_cast<absl::Status>(v));
+  }
+  {
+    CustomType<MyType, kConvToStatus> v;
+    absl::StatusOr<MyType> statusor = v;
+    EXPECT_FALSE(statusor.ok());
+    EXPECT_EQ(statusor.status(), static_cast<absl::Status>(v));
+  }
+  {
+    CustomType<MyType, kConvToT | kConvToStatus> v;
+    absl::StatusOr<MyType> statusor = v;
+    EXPECT_FALSE(statusor.ok());
+    EXPECT_EQ(statusor.status(), static_cast<absl::Status>(v));
+  }
+}
+
+TEST(StatusOr, AssignmentFromT) {
+  // Assign to absl::StatusOr<T> from T when T is convertible to
+  // absl::StatusOr<T>
+  {
+    ConvertibleToAnyStatusOr v;
+    absl::StatusOr<ConvertibleToAnyStatusOr> statusor;
+    statusor = v;
+    EXPECT_TRUE(statusor.ok());
+  }
+  // Assign to absl::StatusOr<T> from T when T is convertible to Status
+  {
+    CustomType<MyType, kConvToStatus> v;
+    absl::StatusOr<CustomType<MyType, kConvToStatus>> statusor;
+    statusor = v;
+    EXPECT_TRUE(statusor.ok());
+  }
+}
+
+TEST(StatusOr, AssignmentFromTypeConvertibleToT) {
+  // Assign to absl::StatusOr<T> from U when U is convertible to T
+  {
+    CustomType<MyType, kConvToT> v;
+    absl::StatusOr<MyType> statusor;
+    statusor = v;
+    EXPECT_TRUE(statusor.ok());
+  }
+}
+
+TEST(StatusOr, AssignmentFromTypeWithConversionOperatortoStatusOrT) {
+  // Assign to absl::StatusOr<T> from U when U has conversion operator to
+  // absl::StatusOr<T>
+  {
+    CustomType<MyType, kConvToStatusOr> v;
+    absl::StatusOr<MyType> statusor;
+    statusor = v;
+    EXPECT_EQ(statusor, v.operator absl::StatusOr<MyType>());
+  }
+  {
+    CustomType<MyType, kConvToT | kConvToStatusOr> v;
+    absl::StatusOr<MyType> statusor;
+    statusor = v;
+    EXPECT_EQ(statusor, v.operator absl::StatusOr<MyType>());
+  }
+  {
+    CustomType<MyType, kConvToStatusOr | kConvToStatus> v;
+    absl::StatusOr<MyType> statusor;
+    statusor = v;
+    EXPECT_EQ(statusor, v.operator absl::StatusOr<MyType>());
+  }
+  {
+    CustomType<MyType, kConvToT | kConvToStatusOr | kConvToStatus> v;
+    absl::StatusOr<MyType> statusor;
+    statusor = v;
+    EXPECT_EQ(statusor, v.operator absl::StatusOr<MyType>());
+  }
+}
+
+TEST(StatusOr, AssignmentFromTypeConvertibleToStatus) {
+  // Assign to absl::StatusOr<T> from U when U is convertible to Status
+  {
+    CustomType<MyType, kConvToStatus> v;
+    absl::StatusOr<MyType> statusor;
+    statusor = v;
+    EXPECT_FALSE(statusor.ok());
+    EXPECT_EQ(statusor.status(), static_cast<absl::Status>(v));
+  }
+  {
+    CustomType<MyType, kConvToT | kConvToStatus> v;
+    absl::StatusOr<MyType> statusor;
+    statusor = v;
+    EXPECT_FALSE(statusor.ok());
+    EXPECT_EQ(statusor.status(), static_cast<absl::Status>(v));
+  }
+}
+
+}  // namespace