Export of internal Abseil changes

--
2f49cb9009386bc67bf54a2908c8720b749c8b7f by Greg Falcon <gfalcon@google.com>:

docs: fix typo

Import of https://github.com/abseil/abseil-cpp/pull/397

PiperOrigin-RevId: 277504420

--
f2bed362c1c12d3fa9c22d11f2b918668e8c37b7 by Abseil Team <absl-team@google.com>:

Avoid our is_[copy/move]_assignable workarounds in MSVC 19.20 and on, since that release introduces a regression that breaks our workaround. We should ideally use the std forms in more cases, but branching when our workarounds fail is simpler to maintain.

PiperOrigin-RevId: 277502334

--
e33de894ffd49848b9e088f59acc9743d1661948 by Derek Mauro <dmauro@google.com>:

Update rules_cc version. The mirror.bazel.build URL does not exist
(cache expiration?)

PiperOrigin-RevId: 277498394

--
b23757b0747c64634d2d701433782c969effef19 by Abseil Team <absl-team@google.com>:

Fix https://github.com/abseil/abseil-cpp/issues/394.

PiperOrigin-RevId: 277491405

--
54c75b8b29813531c52d67cf0ba7063baae4a4f3 by Abseil Team <absl-team@google.com>:

Fix comment typos: waker => waiter.

PiperOrigin-RevId: 277376952

--
874eeaa3b3af808fc88b6355245f643674f5e36e by Abseil Team <absl-team@google.com>:

Don't use atomic ops on waiter and wakeup counts in CONDVAR waiter mode.

Just guard the waiter and wakeup counts with the mutex. This eliminates the
race.

Also fix a typo in the error message for pthread_cond_timedwait.

PiperOrigin-RevId: 277366017

--
ce8c9a63109214519b5a7eaecef2c663c4d566df by Greg Falcon <gfalcon@google.com>:

Implement the config options for our four main C++ forward compatibility types.

These options control whether the names `any`, `optional`, `string_view`, and `variant` in namespace `absl` are aliases to the corresponding C++17 types in namespace `std`.  By default, we continue to auto-detect the configuration of the compiler being run.

These options are not intended to be modified on the command line (as -D flags, say).  Instead, the options.h file can be modified by distributors of Abseil (e.g., binary packagers, maintainers of local copies of Abseil, etc.)

Changing options will change Abseil in an ODR sense.  Any program must only link in a single version of Abseil.  Linking libraries that use Abseil configured with different options is an error: there is no ABI compatibility guarantee when linking different configurations, even if the Abseil versions used are otherwise exactly identical.

PiperOrigin-RevId: 277364298

--
5ed3ad42ae43a05862070f92f9ffd07f5c1f2b81 by Chris Kennelly <ckennelly@google.com>:

Suppress -Wimplicit-int-float-conversion.

On recent builds of Clang, this is an error/warning.

PiperOrigin-RevId: 277346168

--
9b9b0055243c705189bb27d912e6d45a7789cdee by Eric Fiselier <ericwf@google.com>:

Allow building Abseil as a shared library with CMake.

By default CMake's `add_library` creates the target as a static
library. However, users can override the default using the builtin
CMake option -DBUILD_SHARED_LIBS=ON.

This changes Abseil's CMake to respect this configuration option
by removing the explicit `STATIC` in our usages of `add_library`.

PiperOrigin-RevId: 277337753

--
63a8b7b8ede3a9d851916929d6b8537f4f2508ca by Abseil Team <absl-team@google.com>:

Improve AlphaNum Hex performance by using absl::numbers_internal::FastHexToBufferZeroPad16.

PiperOrigin-RevId: 277318108

--
dd047f7e92032682d94b27732df0e4d0670e24a4 by CJ Johnson <johnsoncj@google.com>:

Internal change

PiperOrigin-RevId: 277316913

--
d19ee7074929fed08973cc5b40a844573ce1e0a6 by Abseil Team <absl-team@google.com>:

Handle invoking [[nodiscard]] functions correctly in our tests.

PiperOrigin-RevId: 277301500

--
5373f3737894ba9b8481e95e5f58c7957c00d26a by Chris Kennelly <ckennelly@google.com>:

For internal reasons, loosen visibility restrictions of `//absl/base:malloc_internal`.

As an internal-namespace interface, this module remains unsupported.  We
reserve the right to change, delete, or re-restrict visibility to this target
at any time.

PiperOrigin-RevId: 277118689

--
44e4f6655e05393a375d09b3625c192b1fde5909 by Abseil Team <absl-team@google.com>:

Fix error in example civil day comment.

PiperOrigin-RevId: 277103315

--
7657392b4ce48469106f11cdb952a0bc76a28df3 by Abseil Team <absl-team@google.com>:

Internal change

PiperOrigin-RevId: 277056076

--
c75bda76f40b01fa249b75b5a70c1f5907e56c76 by Abseil Team <absl-team@google.com>:

Suppress lifetime constant-initialization tests when building with MSVC versions > 19.0.

These are broken due to non-compliant initialization order in these versions:
https://developercommunity.visualstudio.com/content/problem/336946/class-with-constexpr-constructor-not-using-static.html
We don't know when Microsoft will fix this bug.

PiperOrigin-RevId: 277049770

--
16c3b9bf2a1796efa57f97b00bcd6227fbccca1f by Matt Calabrese <calabrese@google.com>:

Avoid our is_[copy/move]_assignable workarounds in MSVC 19.20 and on, since that release introduces a regression that breaks our workaround. We should ideally use the std forms in more cases, but branching when our workarounds fail is simpler to maintain.

PiperOrigin-RevId: 277048670

--
e91003fa3ee6026d9b80624a23fc144fa5d74810 by Chris Kennelly <ckennelly@google.com>:

Fix -Wimplicit-int-float-conversion warning in latest clang

PiperOrigin-RevId: 276771618

--
53087ca6603e86ad815f3dd9ab795cc0f79792c1 by Andy Soffer <asoffer@google.com>:

Add documentation on absl::SNPrintF.

PiperOrigin-RevId: 276694032

--
a9426af8cbd4c3a8f9053e7446c821852e41ff61 by Jorg Brown <jorg@google.com>:

Stop including kern/OSByteOrder.h in order to support __APPLE__

Apple compiles with clang now anyway, and clang has support for the
built-in compiler swap functions that are much faster than any function call to
the OS.

PiperOrigin-RevId: 276625231

--
df974be5aa5b4dc1b09c356cb8816edfc7867e63 by Jorg Brown <jorg@google.com>:

Fix the build for Android x86-64 builds, where __SSE4_2__ is defined but
_bswap64 is not.

PiperOrigin-RevId: 276542642

--
d99dc092b3a5ad17643005e55f3b3cb6b9187ccc by Jorg Brown <jorg@google.com>:

Remove a byteswap from the non-SSE path of FastHexToBufferZeroPad16

Remove the need for including absl/base/internal/endian.h from the SSE case
(since if we have the Intel SSE intrinsics, then clearly we also have the
Intel Byte-Swap intrinsics.)

PiperOrigin-RevId: 276532608

--
d67b106dc930d8558810ae3983613bb2ab1e0d36 by Abseil Team <absl-team@google.com>:

Use explicit static_cast<double> for int64_t to double conversion

This uses an explicit static_cast<double>() in the int64_t to double comparisons in duration.cc's SafeAddRepHi. This satisfies clang's -Wimplicit-int-to-float-conversion warning (with https://reviews.llvm.org/D64666). This may also make it easier for humans to realize that the comparison is happening between two floating point double precision values.  It should have no impact on the behavior or generated code.
Tested:
No behavior change
PiperOrigin-RevId: 276529211
GitOrigin-RevId: 2f49cb9009386bc67bf54a2908c8720b749c8b7f
Change-Id: I71e0781893ce219960b8290d54b20532779cb0ff

40 files changed, 451 insertions, 184 deletions

diff --git a/absl/base/BUILD.bazel b/absl/base/BUILD.bazel
index ffeca630706e..6fc712d968f3 100644
--- a/absl/base/BUILD.bazel
+++ b/absl/base/BUILD.bazel
@@ -87,6 +87,7 @@ cc_library(
     name = "config",
     hdrs = [
         "config.h",
+        "options.h",
         "policy_checks.h",
     ],
     copts = ABSL_DEFAULT_COPTS,
@@ -137,7 +138,7 @@ cc_library(
         "//conditions:default": ["-pthread"],
     }) + ABSL_DEFAULT_LINKOPTS,
     visibility = [
-        "//absl:__subpackages__",
+        "//visibility:public",
     ],
     deps = [
         ":base",
diff --git a/absl/base/CMakeLists.txt b/absl/base/CMakeLists.txt
index 2698213c566d..9550cdb2db49 100644
--- a/absl/base/CMakeLists.txt
+++ b/absl/base/CMakeLists.txt
@@ -75,6 +75,7 @@ absl_cc_library(
     config
   HDRS
     "config.h"
+    "options.h"
     "policy_checks.h"
   COPTS
     ${ABSL_DEFAULT_COPTS}
diff --git a/absl/base/config.h b/absl/base/config.h
index 24851fa33ce4..46a84f1a76f6 100644
--- a/absl/base/config.h
+++ b/absl/base/config.h
@@ -63,6 +63,7 @@
 #include <TargetConditionals.h>
 #endif
 
+#include "absl/base/options.h"
 #include "absl/base/policy_checks.h"
 
 // -----------------------------------------------------------------------------
@@ -468,6 +469,68 @@
 #define ABSL_HAVE_STD_STRING_VIEW 1
 #endif
 
+// ABSL_USES_STD_ANY
+//
+// Indicates whether absl::any is an alias for std::any.
+#if !defined(ABSL_OPTION_USE_STD_ANY)
+#error options.h is misconfigured.
+#elif ABSL_OPTION_USE_STD_ANY == 0 || \
+    (ABSL_OPTION_USE_STD_ANY == 2 && !defined(ABSL_HAVE_STD_ANY))
+#undef ABSL_USES_STD_ANY
+#elif ABSL_OPTION_USE_STD_ANY == 1 || \
+    (ABSL_OPTION_USE_STD_ANY == 2 && defined(ABSL_HAVE_STD_ANY))
+#define ABSL_USES_STD_ANY 1
+#else
+#error options.h is misconfigured.
+#endif
+
+// ABSL_USES_STD_OPTIONAL
+//
+// Indicates whether absl::optional is an alias for std::optional.
+#if !defined(ABSL_OPTION_USE_STD_OPTIONAL)
+#error options.h is misconfigured.
+#elif ABSL_OPTION_USE_STD_OPTIONAL == 0 || \
+    (ABSL_OPTION_USE_STD_OPTIONAL == 2 && !defined(ABSL_HAVE_STD_OPTIONAL))
+#undef ABSL_USES_STD_OPTIONAL
+#elif ABSL_OPTION_USE_STD_OPTIONAL == 1 || \
+    (ABSL_OPTION_USE_STD_OPTIONAL == 2 && defined(ABSL_HAVE_STD_OPTIONAL))
+#define ABSL_USES_STD_OPTIONAL 1
+#else
+#error options.h is misconfigured.
+#endif
+
+// ABSL_USES_STD_VARIANT
+//
+// Indicates whether absl::variant is an alias for std::variant.
+#if !defined(ABSL_OPTION_USE_STD_VARIANT)
+#error options.h is misconfigured.
+#elif ABSL_OPTION_USE_STD_VARIANT == 0 || \
+    (ABSL_OPTION_USE_STD_VARIANT == 2 && !defined(ABSL_HAVE_STD_VARIANT))
+#undef ABSL_USES_STD_VARIANT
+#elif ABSL_OPTION_USE_STD_VARIANT == 1 || \
+    (ABSL_OPTION_USE_STD_VARIANT == 2 && defined(ABSL_HAVE_STD_VARIANT))
+#define ABSL_USES_STD_VARIANT 1
+#else
+#error options.h is misconfigured.
+#endif
+
+// ABSL_USES_STD_STRING_VIEW
+//
+// Indicates whether absl::string_view is an alias for std::string_view.
+#if !defined(ABSL_OPTION_USE_STD_STRING_VIEW)
+#error options.h is misconfigured.
+#elif ABSL_OPTION_USE_STD_STRING_VIEW == 0 || \
+    (ABSL_OPTION_USE_STD_STRING_VIEW == 2 &&  \
+     !defined(ABSL_HAVE_STD_STRING_VIEW))
+#undef ABSL_USES_STD_STRING_VIEW
+#elif ABSL_OPTION_USE_STD_STRING_VIEW == 1 || \
+    (ABSL_OPTION_USE_STD_STRING_VIEW == 2 &&  \
+     defined(ABSL_HAVE_STD_STRING_VIEW))
+#define ABSL_USES_STD_STRING_VIEW 1
+#else
+#error options.h is misconfigured.
+#endif
+
 // In debug mode, MSVC 2017's std::variant throws a EXCEPTION_ACCESS_VIOLATION
 // SEH exception from emplace for variant<SomeStruct> when constructing the
 // struct can throw. This defeats some of variant_test and
diff --git a/absl/base/internal/endian.h b/absl/base/internal/endian.h
index b43c9a46ee35..8233cb52433b 100644
--- a/absl/base/internal/endian.h
+++ b/absl/base/internal/endian.h
@@ -19,9 +19,6 @@
 // The following guarantees declaration of the byte swap functions
 #ifdef _MSC_VER
 #include <stdlib.h>  // NOLINT(build/include)
-#elif defined(__APPLE__)
-// macOS / Darwin features
-#include <libkern/OSByteOrder.h>
 #elif defined(__FreeBSD__)
 #include <sys/endian.h>
 #elif defined(__GLIBC__)
@@ -63,11 +60,6 @@ inline uint16_t gbswap_16(uint16_t host_int) {
   return _byteswap_ushort(host_int);
 }
 
-#elif defined(__APPLE__)
-inline uint64_t gbswap_64(uint64_t host_int) { return OSSwapInt16(host_int); }
-inline uint32_t gbswap_32(uint32_t host_int) { return OSSwapInt32(host_int); }
-inline uint16_t gbswap_16(uint16_t host_int) { return OSSwapInt64(host_int); }
-
 #else
 inline uint64_t gbswap_64(uint64_t host_int) {
 #if defined(__GNUC__) && defined(__x86_64__) && !defined(__APPLE__)
diff --git a/absl/base/options.h b/absl/base/options.h
new file mode 100644
index 000000000000..3961e63f4e2a
--- /dev/null
+++ b/absl/base/options.h
@@ -0,0 +1,188 @@
+#ifndef ABSL_BASE_OPTIONS_H_
+#define ABSL_BASE_OPTIONS_H_
+
+// 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: options.h
+// -----------------------------------------------------------------------------
+//
+// This file contains Abseil configuration options for setting specific
+// implementations instead of letting Abseil determine which implementation to
+// use at compile-time. Setting these options may be useful for package or build
+// managers who wish to guarantee ABI stability within binary builds (which are
+// otherwise difficult to enforce).
+//
+// *** IMPORTANT NOTICE FOR PACKAGE MANAGERS:  It is important that
+// maintainers of package managers who wish to package Abseil read and
+// understand this file! ***
+//
+// Abseil contains a number of possible configuration endpoints, based on
+// parameters such as the detected platform, language version, or command-line
+// flags used to invoke the underlying binary. As is the case with all
+// libraries, binaries which contain Abseil code must ensure that separate
+// packages use the same compiled copy of Abseil to avoid a diamond dependency
+// problem, which can occur if two packages built with different Abseil
+// configuration settings are linked together. Diamond dependency problems in
+// C++ may manifest as violations to the One Definition Rule (ODR) (resulting in
+// linker errors), or undefined behavior (resulting in crashes).
+//
+// Diamond dependency problems can be avoided if all packages utilize the same
+// exact version of Abseil. Building from source code with the same compilation
+// parameters is the easiest way to avoid such dependency problems. However, for
+// package managers who cannot control such compilation parameters, we are
+// providing the file to allow you to inject ABI (Application Binary Interface)
+// stability across builds. Settings options in this file will neither change
+// API nor ABI, providing a stable copy of Abseil between packages.
+//
+// Care must be taken to keep options within these configurations isolated
+// from any other dynamic settings, such as command-line flags which could alter
+// these options. This file is provided specifically to help build and package
+// managers provide a stable copy of Abseil within their libraries and binaries;
+// other developers should not have need to alter the contents of this file.
+//
+// -----------------------------------------------------------------------------
+// Usage
+// -----------------------------------------------------------------------------
+//
+// For any particular package release, set the appropriate definitions within
+// this file to whatever value makes the most sense for your package(s). Note
+// that, by default, most of these options, at the moment, affect the
+// implementation of types; future options may affect other implementation
+// details.
+//
+// NOTE: the defaults within this file all assume that Abseil can select the
+// proper Abseil implementation at compile-time, which will not be sufficient
+// to guarantee ABI stability to package managers.
+//
+// -----------------------------------------------------------------------------
+// Type Compatibility Options
+// -----------------------------------------------------------------------------
+//
+// ABSL_OPTION_USE_STD_ANY
+//
+// This option controls whether absl::any is implemented as an alias to
+// std::any, or as an independent implementation.
+//
+// A value of 0 means to use Abseil's implementation.  This requires only C++11
+// support, and is expected to work on every toolchain we support.
+//
+// A value of 1 means to use an alias to std::any.  This requires that all code
+// using Abseil is built in C++17 mode or later.
+//
+// A value of 2 means to detect the C++ version being used to compile Abseil,
+// and use an alias only if a working std::any is available.  This option is
+// useful when you are building your entire program, including all of its
+// dependencies, from source.  It should not be used otherwise -- for example,
+// if you are distributing Abseil in a binary package manager -- since in
+// mode 2, absl::any will name a different type, with a different mangled name
+// and binary layout, depending on the compiler flags passed by the end user.
+// For more info, see https://abseil.io/about/design/dropin-types.
+//
+// User code should not inspect this macro.  To check in the preprocessor if
+// absl::any is a typedef of std::any, use the feature macro ABSL_USES_STD_ANY.
+
+#define ABSL_OPTION_USE_STD_ANY 2
+
+
+// ABSL_OPTION_USE_STD_OPTIONAL
+//
+// This option controls whether absl::optional is implemented as an alias to
+// std::optional, or as an independent implementation.
+//
+// A value of 0 means to use Abseil's implementation.  This requires only C++11
+// support, and is expected to work on every toolchain we support.
+//
+// A value of 1 means to use an alias to std::optional.  This requires that all
+// code using Abseil is built in C++17 mode or later.
+//
+// A value of 2 means to detect the C++ version being used to compile Abseil,
+// and use an alias only if a working std::optional is available.  This option
+// is useful when you are building your program from source.  It should not be
+// used otherwise -- for example, if you are distributing Abseil in a binary
+// package manager -- since in mode 2, absl::optional will name a different
+// type, with a different mangled name and binary layout, depending on the
+// compiler flags passed by the end user.  For more info, see
+// https://abseil.io/about/design/dropin-types.
+
+// A value of 2 means to detect the C++ version being used to compile Abseil,
+// and use an alias only if a working std::optional is available.  This option
+// should not be used when your program is not built from source -- for example,
+// if you are distributing Abseil in a binary package manager -- since in mode
+// 2, absl::optional will name a different template class, with a different
+// mangled name and binary layout, depending on the compiler flags passed by the
+// end user.
+//
+// User code should not inspect this macro.  To check in the preprocessor if
+// absl::optional is a typedef of std::optional, use the feature macro
+// ABSL_USES_STD_OPTIONAL.
+
+#define ABSL_OPTION_USE_STD_OPTIONAL 2
+
+
+// ABSL_OPTION_USE_STD_STRING_VIEW
+//
+// This option controls whether absl::string_view is implemented as an alias to
+// std::string_view, or as an independent implementation.
+//
+// A value of 0 means to use Abseil's implementation.  This requires only C++11
+// support, and is expected to work on every toolchain we support.
+//
+// A value of 1 means to use an alias to std::string_view.  This requires that
+// all code using Abseil is built in C++17 mode or later.
+//
+// A value of 2 means to detect the C++ version being used to compile Abseil,
+// and use an alias only if a working std::string_view is available.  This
+// option is useful when you are building your program from source.  It should
+// not be used otherwise -- for example, if you are distributing Abseil in a
+// binary package manager -- since in mode 2, absl::string_view will name a
+// different type, with a different mangled name and binary layout, depending on
+// the compiler flags passed by the end user.  For more info, see
+// https://abseil.io/about/design/dropin-types.
+//
+// User code should not inspect this macro.  To check in the preprocessor if
+// absl::string_view is a typedef of std::string_view, use the feature macro
+// ABSL_USES_STD_STRING_VIEW.
+
+#define ABSL_OPTION_USE_STD_STRING_VIEW 2
+
+
+// ABSL_OPTION_USE_STD_VARIANT
+//
+// This option controls whether absl::variant is implemented as an alias to
+// std::variant, or as an independent implementation.
+//
+// A value of 0 means to use Abseil's implementation.  This requires only C++11
+// support, and is expected to work on every toolchain we support.
+//
+// A value of 1 means to use an alias to std::variant.  This requires that all
+// code using Abseil is built in C++17 mode or later.
+//
+// A value of 2 means to detect the C++ version being used to compile Abseil,
+// and use an alias only if a working std::variant is available.  This option
+// is useful when you are building your program from source.  It should not be
+// used otherwise -- for example, if you are distributing Abseil in a binary
+// package manager -- since in mode 2, absl::variant will name a different
+// type, with a different mangled name and binary layout, depending on the
+// compiler flags passed by the end user.  For more info, see
+// https://abseil.io/about/design/dropin-types.
+//
+// User code should not inspect this macro.  To check in the preprocessor if
+// absl::variant is a typedef of std::variant, use the feature macro
+// ABSL_USES_STD_VARIANT.
+
+#define ABSL_OPTION_USE_STD_VARIANT 2
+
+#endif  // ABSL_BASE_OPTIONS_H_
diff --git a/absl/container/flat_hash_map_test.cc b/absl/container/flat_hash_map_test.cc
index 6cff1a25716f..02d1f879dae1 100644
--- a/absl/container/flat_hash_map_test.cc
+++ b/absl/container/flat_hash_map_test.cc
@@ -214,7 +214,7 @@ TEST(FlatHashMap, MergeExtractInsert) {
   EXPECT_THAT(m, UnorderedElementsAre(Pair(1, 17), Pair(2, 9)));
 }
 
-#if (defined(ABSL_HAVE_STD_ANY) || !defined(_LIBCPP_VERSION)) && \
+#if (defined(ABSL_USES_STD_ANY) || !defined(_LIBCPP_VERSION)) && \
     !defined(__EMSCRIPTEN__)
 TEST(FlatHashMap, Any) {
   absl::flat_hash_map<int, absl::any> m;
@@ -246,7 +246,7 @@ TEST(FlatHashMap, Any) {
   ASSERT_NE(it2, m2.end());
   EXPECT_EQ(7, it2->second);
 }
-#endif  // (defined(ABSL_HAVE_STD_ANY) || !defined(_LIBCPP_VERSION)) &&
+#endif  // (defined(ABSL_USES_STD_ANY) || !defined(_LIBCPP_VERSION)) &&
         // !defined(__EMSCRIPTEN__)
 
 }  // namespace
diff --git a/absl/container/internal/inlined_vector.h b/absl/container/internal/inlined_vector.h
index 7d08f7e306e4..f678c88dafd5 100644
--- a/absl/container/internal/inlined_vector.h
+++ b/absl/container/internal/inlined_vector.h
@@ -471,12 +471,9 @@ auto Storage<T, N, A>::Initialize(ValueAdapter values, size_type new_size)
     // safe to take on the allocation with size `0`. If `ConstructElements(...)`
     // throws, deallocation will be automatically handled by `~Storage()`.
     size_type new_capacity = ComputeCapacity(GetInlinedCapacity(), new_size);
-    pointer new_data = AllocatorTraits::allocate(*GetAllocPtr(), new_capacity);
-
-    SetAllocatedData(new_data, new_capacity);
+    construct_data = AllocatorTraits::allocate(*GetAllocPtr(), new_capacity);
+    SetAllocatedData(construct_data, new_capacity);
     SetIsAllocated();
-
-    construct_data = new_data;
   } else {
     construct_data = GetInlinedData();
   }
@@ -503,9 +500,7 @@ auto Storage<T, N, A>::Assign(ValueAdapter values, size_type new_size) -> void {
 
   if (new_size > storage_view.capacity) {
     size_type new_capacity = ComputeCapacity(storage_view.capacity, new_size);
-    pointer new_data = allocation_tx.Allocate(new_capacity);
-
-    construct_loop = {new_data, new_size};
+    construct_loop = {allocation_tx.Allocate(new_capacity), new_size};
     destroy_loop = {storage_view.data, storage_view.size};
   } else if (new_size > storage_view.size) {
     assign_loop = {storage_view.data, storage_view.size};
@@ -552,7 +547,6 @@ auto Storage<T, N, A>::Resize(ValueAdapter values, size_type new_size) -> void {
   if (new_size > storage_view.capacity) {
     size_type new_capacity = ComputeCapacity(storage_view.capacity, new_size);
     pointer new_data = allocation_tx.Allocate(new_capacity);
-
     construct_loop = {new_data + storage_view.size,
                       new_size - storage_view.size};
     move_construct_loop = {new_data, storage_view.size};
@@ -690,14 +684,14 @@ auto Storage<T, N, A>::EmplaceBack(Args&&... args) -> reference {
   pointer construct_data;
   if (storage_view.size == storage_view.capacity) {
     size_type new_capacity = NextCapacity(storage_view.capacity);
-    pointer new_data = allocation_tx.Allocate(new_capacity);
-
-    construct_data = new_data;
+    construct_data = allocation_tx.Allocate(new_capacity);
   } else {
     construct_data = storage_view.data;
   }
 
-  AllocatorTraits::construct(*GetAllocPtr(), construct_data + storage_view.size,
+  pointer last_ptr = construct_data + storage_view.size;
+
+  AllocatorTraits::construct(*GetAllocPtr(), last_ptr,
                              std::forward<Args>(args)...);
 
   if (allocation_tx.DidAllocate()) {
@@ -707,8 +701,7 @@ auto Storage<T, N, A>::EmplaceBack(Args&&... args) -> reference {
           storage_view.size);
     }
     ABSL_INTERNAL_CATCH_ANY {
-      AllocatorTraits::destroy(*GetAllocPtr(),
-                               construct_data + storage_view.size);
+      AllocatorTraits::destroy(*GetAllocPtr(), last_ptr);
       ABSL_INTERNAL_RETHROW;
     }
 
@@ -721,7 +714,7 @@ auto Storage<T, N, A>::EmplaceBack(Args&&... args) -> reference {
   }
 
   AddSize(1);
-  return *(construct_data + storage_view.size);
+  return *last_ptr;
 }
 
 template <typename T, size_t N, typename A>
@@ -793,9 +786,7 @@ auto Storage<T, N, A>::ShrinkToFit() -> void {
   pointer construct_data;
   if (storage_view.size > GetInlinedCapacity()) {
     size_type new_capacity = storage_view.size;
-    pointer new_data = allocation_tx.Allocate(new_capacity);
-
-    construct_data = new_data;
+    construct_data = allocation_tx.Allocate(new_capacity);
   } else {
     construct_data = GetInlinedData();
   }
diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h
index 9992ba4b8ac0..9079a73e52a6 100644
--- a/absl/container/internal/raw_hash_set.h
+++ b/absl/container/internal/raw_hash_set.h
@@ -668,7 +668,7 @@ class raw_hash_set {
     }
 
     ctrl_t* ctrl_ = nullptr;
-    // To avoid uninitialized member warnigs, put slot_ in an anonymous union.
+    // To avoid uninitialized member warnings, put slot_ in an anonymous union.
     // The member is not initialized on singleton and end iterators.
     union {
       slot_type* slot_;
diff --git a/absl/meta/type_traits.h b/absl/meta/type_traits.h
index 76959cdef602..d57a87923136 100644
--- a/absl/meta/type_traits.h
+++ b/absl/meta/type_traits.h
@@ -145,6 +145,18 @@ using IsMoveAssignableImpl = decltype(std::declval<T&>() = std::declval<T&&>());
 
 }  // namespace type_traits_internal
 
+// MSVC 19.20 has a regression that causes our workarounds to fail, but their
+// std forms now appear to be compliant.
+#if defined(_MSC_VER) && !defined(__clang__) && (_MSC_VER >= 1920)
+
+template <typename T>
+using is_copy_assignable = std::is_copy_assignable<T>;
+
+template <typename T>
+using is_move_assignable = std::is_move_assignable<T>;
+
+#else
+
 template <typename T>
 struct is_copy_assignable : type_traits_internal::is_detected<
                                 type_traits_internal::IsCopyAssignableImpl, T> {
@@ -155,6 +167,8 @@ struct is_move_assignable : type_traits_internal::is_detected<
                                 type_traits_internal::IsMoveAssignableImpl, T> {
 };
 
+#endif
+
 // void_t()
 //
 // Ignores the type of any its arguments and returns `void`. In general, this
diff --git a/absl/random/internal/nonsecure_base_test.cc b/absl/random/internal/nonsecure_base_test.cc
index d9de99019ce0..698027fc6e0d 100644
--- a/absl/random/internal/nonsecure_base_test.cc
+++ b/absl/random/internal/nonsecure_base_test.cc
@@ -154,9 +154,10 @@ TEST(NonsecureURBGBase, CompatibleWithDistributionUtils) {
 TEST(NonsecureURBGBase, CompatibleWithStdDistributions) {
   ExampleNonsecureURBG rbg;
 
-  std::uniform_int_distribution<uint32_t>(0, 100)(rbg);
-  std::uniform_real_distribution<float>()(rbg);
-  std::bernoulli_distribution(0.2)(rbg);
+  // Cast to void to suppress [[nodiscard]] warnings
+  static_cast<void>(std::uniform_int_distribution<uint32_t>(0, 100)(rbg));
+  static_cast<void>(std::uniform_real_distribution<float>()(rbg));
+  static_cast<void>(std::bernoulli_distribution(0.2)(rbg));
 }
 
 TEST(NonsecureURBGBase, ConsecutiveDefaultInstancesYieldUniqueVariates) {
diff --git a/absl/random/log_uniform_int_distribution.h b/absl/random/log_uniform_int_distribution.h
index 956a69070ccd..de58bdbe14ca 100644
--- a/absl/random/log_uniform_int_distribution.h
+++ b/absl/random/log_uniform_int_distribution.h
@@ -192,13 +192,15 @@ log_uniform_int_distribution<IntType>::Generate(
     const double r = std::pow(p.base(), d);
     const double s = (r * p.base()) - 1.0;
 
-    base_e = (r > (std::numeric_limits<unsigned_type>::max)())
-                 ? (std::numeric_limits<unsigned_type>::max)()
-                 : static_cast<unsigned_type>(r);
-
-    top_e = (s > (std::numeric_limits<unsigned_type>::max)())
-                ? (std::numeric_limits<unsigned_type>::max)()
-                : static_cast<unsigned_type>(s);
+    base_e =
+        (r > static_cast<double>((std::numeric_limits<unsigned_type>::max)()))
+            ? (std::numeric_limits<unsigned_type>::max)()
+            : static_cast<unsigned_type>(r);
+
+    top_e =
+        (s > static_cast<double>((std::numeric_limits<unsigned_type>::max)()))
+            ? (std::numeric_limits<unsigned_type>::max)()
+            : static_cast<unsigned_type>(s);
   }
 
   const unsigned_type lo = (base_e >= p.range()) ? p.range() : base_e;
diff --git a/absl/strings/numbers.h b/absl/strings/numbers.h
index 745de67ad86d..9b8ec89a8941 100644
--- a/absl/strings/numbers.h
+++ b/absl/strings/numbers.h
@@ -37,7 +37,14 @@
 #include <type_traits>
 
 #include "absl/base/internal/bits.h"
+#ifdef __SSE4_2__
+// TODO(jorg): Remove this when we figure out the right way
+// to swap bytes on SSE 4.2 that works with the compilers
+// we claim to support.  Also, add tests for the compiler
+// that doesn't support the Intel _bswap64 intrinsic but
+// does support all the SSE 4.2 intrinsics
 #include "absl/base/internal/endian.h"
+#endif
 #include "absl/base/macros.h"
 #include "absl/base/port.h"
 #include "absl/numeric/int128.h"
@@ -189,12 +196,12 @@ ABSL_MUST_USE_RESULT bool safe_strtoi_base(absl::string_view s, int_type* out,
 // Returns the number of non-pad digits of the output (it can never be zero
 // since 0 has one digit).
 inline size_t FastHexToBufferZeroPad16(uint64_t val, char* out) {
-  uint64_t be = absl::big_endian::FromHost64(val);
 #ifdef __SSE4_2__
+  uint64_t be = absl::big_endian::FromHost64(val);
   const auto kNibbleMask = _mm_set1_epi8(0xf);
   const auto kHexDigits = _mm_setr_epi8('0', '1', '2', '3', '4', '5', '6', '7',
                                         '8', '9', 'a', 'b', 'c', 'd', 'e', 'f');
-  auto v = _mm_loadu_si64(reinterpret_cast<__m128i*>(&be));  // load lo dword
+  auto v = _mm_loadl_epi64(reinterpret_cast<__m128i*>(&be));  // load lo dword
   auto v4 = _mm_srli_epi64(v, 4);                            // shift 4 right
   auto il = _mm_unpacklo_epi8(v4, v);                        // interleave bytes
   auto m = _mm_and_si128(il, kNibbleMask);                   // mask out nibbles
@@ -202,7 +209,7 @@ inline size_t FastHexToBufferZeroPad16(uint64_t val, char* out) {
   _mm_storeu_si128(reinterpret_cast<__m128i*>(out), hexchars);
 #else
   for (int i = 0; i < 8; ++i) {
-    auto byte = (be >> (8 * i)) & 0xFF;
+    auto byte = (val >> (56 - 8 * i)) & 0xFF;
     auto* hex = &absl::numbers_internal::kHexTable[byte * 2];
     std::memcpy(out + 2 * i, hex, 2);
   }
diff --git a/absl/strings/str_cat.cc b/absl/strings/str_cat.cc
index d587789972e4..4bd56f5f4386 100644
--- a/absl/strings/str_cat.cc
+++ b/absl/strings/str_cat.cc
@@ -27,23 +27,21 @@
 namespace absl {
 
 AlphaNum::AlphaNum(Hex hex) {
+  static_assert(numbers_internal::kFastToBufferSize >= 32,
+                "This function only works when output buffer >= 32 bytes long");
   char* const end = &digits_[numbers_internal::kFastToBufferSize];
-  char* writer = end;
-  uint64_t value = hex.value;
-  do {
-    *--writer = absl::numbers_internal::kHexChar[value & 0xF];
-    value >>= 4;
-  } while (value != 0);
-
-  char* beg;
-  if (end - writer < hex.width) {
-    beg = end - hex.width;
-    std::fill_n(beg, writer - beg, hex.fill);
+  auto real_width =
+      absl::numbers_internal::FastHexToBufferZeroPad16(hex.value, end - 16);
+  if (real_width >= hex.width) {
+    piece_ = absl::string_view(end - real_width, real_width);
   } else {
-    beg = writer;
+    // Pad first 16 chars because FastHexToBufferZeroPad16 pads only to 16 and
+    // max pad width can be up to 20.
+    std::memset(end - 32, hex.fill, 16);
+    // Patch up everything else up to the real_width.
+    std::memset(end - real_width - 16, hex.fill, 16);
+    piece_ = absl::string_view(end - hex.width, hex.width);
   }
-
-  piece_ = absl::string_view(beg, end - beg);
 }
 
 AlphaNum::AlphaNum(Dec dec) {
diff --git a/absl/strings/str_format.h b/absl/strings/str_format.h
index 607e2bcaae16..c11c93a24837 100644
--- a/absl/strings/str_format.h
+++ b/absl/strings/str_format.h
@@ -400,6 +400,12 @@ int FPrintF(std::FILE* output, const FormatSpec<Args...>& format,
 // This function is functionally equivalent to `std::snprintf()` (and
 // type-safe); prefer `absl::SNPrintF()` over `std::snprintf()`.
 //
+// In particular, a successful call to `absl::SNPrintF()` writes at most `size`
+// bytes of the formatted output to `output`, including a null terminator, and
+// returns the number of bytes that would have been written if truncation did
+// not occur. In the event of an error, a negative value is returned and `errno`
+// is set.
+//
 // Example:
 //
 //   std::string_view s = "Ulaanbaatar";
diff --git a/absl/strings/string_view.cc b/absl/strings/string_view.cc
index dc034a83eea8..d5e1a3de9ff3 100644
--- a/absl/strings/string_view.cc
+++ b/absl/strings/string_view.cc
@@ -14,7 +14,7 @@
 
 #include "absl/strings/string_view.h"
 
-#ifndef ABSL_HAVE_STD_STRING_VIEW
+#ifndef ABSL_USES_STD_STRING_VIEW
 
 #include <algorithm>
 #include <climits>
@@ -230,4 +230,4 @@ constexpr string_view::size_type string_view::kMaxSize;
 
 }  // namespace absl
 
-#endif  // ABSL_HAVE_STD_STRING_VIEW
+#endif  // ABSL_USES_STD_STRING_VIEW
diff --git a/absl/strings/string_view.h b/absl/strings/string_view.h
index 3438ccc12a7d..07075e80ec64 100644
--- a/absl/strings/string_view.h
+++ b/absl/strings/string_view.h
@@ -30,7 +30,7 @@
 #include <algorithm>
 #include "absl/base/config.h"
 
-#ifdef ABSL_HAVE_STD_STRING_VIEW
+#ifdef ABSL_USES_STD_STRING_VIEW
 
 #include <string_view>  // IWYU pragma: export
 
@@ -38,7 +38,7 @@ namespace absl {
 using std::string_view;
 }  // namespace absl
 
-#else  // ABSL_HAVE_STD_STRING_VIEW
+#else  // ABSL_USES_STD_STRING_VIEW
 
 #if ABSL_HAVE_BUILTIN(__builtin_memcmp) || \
     (defined(__GNUC__) && !defined(__clang__))
@@ -580,7 +580,7 @@ std::ostream& operator<<(std::ostream& o, string_view piece);
 
 #undef ABSL_INTERNAL_STRING_VIEW_MEMCMP
 
-#endif  // ABSL_HAVE_STD_STRING_VIEW
+#endif  // ABSL_USES_STD_STRING_VIEW
 
 namespace absl {
 
diff --git a/absl/strings/string_view_test.cc b/absl/strings/string_view_test.cc
index 86f2fbcd003a..96dacdf048cf 100644
--- a/absl/strings/string_view_test.cc
+++ b/absl/strings/string_view_test.cc
@@ -830,7 +830,7 @@ TEST(StringViewTest, FrontBackSingleChar) {
 // to the standard, but `absl::string_view` implements a different
 // behavior for historical reasons. We work around tests that construct
 // `string_view` from `nullptr` when using libc++.
-#if !defined(ABSL_HAVE_STD_STRING_VIEW) ||                    \
+#if !defined(ABSL_USES_STD_STRING_VIEW) ||                    \
     (!(defined(_GLIBCXX_RELEASE) && _GLIBCXX_RELEASE >= 9) && \
      !defined(_LIBCPP_VERSION) && !defined(_MSC_VER))
 #define ABSL_HAVE_STRING_VIEW_FROM_NULLPTR 1
@@ -938,7 +938,7 @@ TEST(StringViewTest, ConstexprCompiles) {
 #endif
   constexpr absl::string_view cstr_len("cstr", 4);
 
-#if defined(ABSL_HAVE_STD_STRING_VIEW)
+#if defined(ABSL_USES_STD_STRING_VIEW)
   // In libstdc++ (as of 7.2), `std::string_view::string_view(const char*)`
   // calls `std::char_traits<char>::length(const char*)` to get the std::string
   // length, but it is not marked constexpr yet. See GCC bug:
@@ -952,7 +952,7 @@ TEST(StringViewTest, ConstexprCompiles) {
 #define ABSL_HAVE_CONSTEXPR_STRING_VIEW_FROM_CSTR 1
 #endif  // !__GLIBCXX__
 
-#else  // ABSL_HAVE_STD_STRING_VIEW
+#else  // ABSL_USES_STD_STRING_VIEW
 
 // This duplicates the check for __builtin_strlen in the header.
 #if ABSL_HAVE_BUILTIN(__builtin_strlen) || \
@@ -967,7 +967,7 @@ TEST(StringViewTest, ConstexprCompiles) {
 #define ABSL_HAVE_CONSTEXPR_STRING_VIEW_FROM_CSTR 1
 #endif
 
-#endif  // ABSL_HAVE_STD_STRING_VIEW
+#endif  // ABSL_USES_STD_STRING_VIEW
 
 #ifdef ABSL_HAVE_CONSTEXPR_STRING_VIEW_FROM_CSTR
   constexpr absl::string_view cstr_strlen("foo");
@@ -1136,7 +1136,7 @@ TEST(HugeStringView, TwoPointTwoGB) {
 }
 #endif  // THREAD_SANITIZER
 
-#if !defined(NDEBUG) && !defined(ABSL_HAVE_STD_STRING_VIEW)
+#if !defined(NDEBUG) && !defined(ABSL_USES_STD_STRING_VIEW)
 TEST(NonNegativeLenTest, NonNegativeLen) {
   ABSL_EXPECT_DEATH_IF_SUPPORTED(absl::string_view("xyz", -1),
                                  "len <= kMaxSize");
@@ -1152,7 +1152,7 @@ TEST(LenExceedsMaxSizeTest, LenExceedsMaxSize) {
   ABSL_EXPECT_DEATH_IF_SUPPORTED(absl::string_view("", max_size + 1),
                                  "len <= kMaxSize");
 }
-#endif  // !defined(NDEBUG) && !defined(ABSL_HAVE_STD_STRING_VIEW)
+#endif  // !defined(NDEBUG) && !defined(ABSL_USES_STD_STRING_VIEW)
 
 class StringViewStreamTest : public ::testing::Test {
  public:
diff --git a/absl/synchronization/internal/waiter.cc b/absl/synchronization/internal/waiter.cc
index d83d8087f8d5..2f41aa5f2b44 100644
--- a/absl/synchronization/internal/waiter.cc
+++ b/absl/synchronization/internal/waiter.cc
@@ -161,7 +161,7 @@ bool Waiter::Wait(KernelTimeout t) {
 
 void Waiter::Post() {
   if (futex_.fetch_add(1, std::memory_order_release) == 0) {
-    // We incremented from 0, need to wake a potential waker.
+    // We incremented from 0, need to wake a potential waiter.
     Poke();
   }
 }
@@ -210,8 +210,8 @@ void Waiter::Init() {
     ABSL_RAW_LOG(FATAL, "pthread_cond_init failed: %d", err2);
   }
 
-  waiter_count_.store(0, std::memory_order_relaxed);
-  wakeup_count_.store(0, std::memory_order_relaxed);
+  waiter_count_ = 0;
+  wakeup_count_ = 0;
 }
 
 bool Waiter::Wait(KernelTimeout t) {
@@ -221,24 +221,12 @@ bool Waiter::Wait(KernelTimeout t) {
   }
 
   PthreadMutexHolder h(&mu_);
-  waiter_count_.fetch_add(1, std::memory_order_relaxed);
+  ++waiter_count_;
   // Loop until we find a wakeup to consume or timeout.
   // Note that, since the thread ticker is just reset, we don't need to check
   // whether the thread is idle on the very first pass of the loop.
   bool first_pass = true;
-  while (true) {
-    int x = wakeup_count_.load(std::memory_order_relaxed);
-    if (x != 0) {
-      if (!wakeup_count_.compare_exchange_weak(x, x - 1,
-                                               std::memory_order_acquire,
-                                               std::memory_order_relaxed)) {
-        continue;  // Raced with someone, retry.
-      }
-      // Successfully consumed a wakeup, we're done.
-      waiter_count_.fetch_sub(1, std::memory_order_relaxed);
-      return true;
-    }
-
+  while (wakeup_count_ == 0) {
     if (!first_pass) MaybeBecomeIdle();
     // No wakeups available, time to wait.
     if (!t.has_timeout()) {
@@ -249,34 +237,38 @@ bool Waiter::Wait(KernelTimeout t) {
     } else {
       const int err = pthread_cond_timedwait(&cv_, &mu_, &abs_timeout);
       if (err == ETIMEDOUT) {
-        waiter_count_.fetch_sub(1, std::memory_order_relaxed);
+        --waiter_count_;
         return false;
       }
       if (err != 0) {
-        ABSL_RAW_LOG(FATAL, "pthread_cond_wait failed: %d", err);
+        ABSL_RAW_LOG(FATAL, "pthread_cond_timedwait failed: %d", err);
       }
     }
     first_pass = false;
   }
+  // Consume a wakeup and we're done.
+  --wakeup_count_;
+  --waiter_count_;
+  return true;
 }
 
 void Waiter::Post() {
-  wakeup_count_.fetch_add(1, std::memory_order_release);
-  Poke();
+  PthreadMutexHolder h(&mu_);
+  ++wakeup_count_;
+  InternalCondVarPoke();
 }
 
 void Waiter::Poke() {
-  if (waiter_count_.load(std::memory_order_relaxed) == 0) {
-    return;
-  }
-  // Potentially a waker. Take the lock and check again.
   PthreadMutexHolder h(&mu_);
-  if (waiter_count_.load(std::memory_order_relaxed) == 0) {
-    return;
-  }
-  const int err = pthread_cond_signal(&cv_);
-  if (err != 0) {
-    ABSL_RAW_LOG(FATAL, "pthread_cond_signal failed: %d", err);
+  InternalCondVarPoke();
+}
+
+void Waiter::InternalCondVarPoke() {
+  if (waiter_count_ != 0) {
+    const int err = pthread_cond_signal(&cv_);
+    if (ABSL_PREDICT_FALSE(err != 0)) {
+      ABSL_RAW_LOG(FATAL, "pthread_cond_signal failed: %d", err);
+    }
   }
 }
 
@@ -456,7 +448,7 @@ void Waiter::Poke() {
   if (waiter_count_.load(std::memory_order_relaxed) == 0) {
     return;
   }
-  // Potentially a waker. Take the lock and check again.
+  // Potentially a waiter. Take the lock and check again.
   LockHolder h(WinHelper::GetLock(this));
   if (waiter_count_.load(std::memory_order_relaxed) == 0) {
     return;
diff --git a/absl/synchronization/internal/waiter.h b/absl/synchronization/internal/waiter.h
index 099935453bee..c23897007e70 100644
--- a/absl/synchronization/internal/waiter.h
+++ b/absl/synchronization/internal/waiter.h
@@ -106,10 +106,13 @@ class Waiter {
   static_assert(sizeof(int32_t) == sizeof(futex_), "Wrong size for futex");
 
 #elif ABSL_WAITER_MODE == ABSL_WAITER_MODE_CONDVAR
+  // REQUIRES: mu_ must be held.
+  void InternalCondVarPoke();
+
   pthread_mutex_t mu_;
   pthread_cond_t cv_;
-  std::atomic<int> waiter_count_;
-  std::atomic<int> wakeup_count_;  // Unclaimed wakeups, written under lock.
+  int waiter_count_;
+  int wakeup_count_;  // Unclaimed wakeups.
 
 #elif ABSL_WAITER_MODE == ABSL_WAITER_MODE_SEM
   sem_t sem_;
diff --git a/absl/synchronization/lifetime_test.cc b/absl/synchronization/lifetime_test.cc
index 34b8875b4b70..cc973a329071 100644
--- a/absl/synchronization/lifetime_test.cc
+++ b/absl/synchronization/lifetime_test.cc
@@ -122,6 +122,11 @@ class OnDestruction {
   Function fn_;
 };
 
+// These tests require that the compiler correctly supports C++11 constant
+// initialization... but MSVC has a known regression since v19.10:
+// https://developercommunity.visualstudio.com/content/problem/336946/class-with-constexpr-constructor-not-using-static.html
+// TODO(epastor): Limit the affected range once MSVC fixes this bug.
+#if defined(__clang__) || !(defined(_MSC_VER) && _MSC_VER > 1900)
 // kConstInit
 // Test early usage.  (Declaration comes first; definitions must appear after
 // the test runner.)
@@ -151,6 +156,7 @@ OnConstruction check_still_locked([]() ABSL_NO_THREAD_SAFETY_ANALYSIS {
   const_init_sanity_mutex.AssertHeld();
   const_init_sanity_mutex.Unlock();
 });
+#endif  // defined(__clang__) || !(defined(_MSC_VER) && _MSC_VER > 1900)
 
 // Test shutdown usage.  (Declarations come first; definitions must appear after
 // the test runner.)
diff --git a/absl/time/civil_time.h b/absl/time/civil_time.h
index c8166d07c94e..77c3be2eba6b 100644
--- a/absl/time/civil_time.h
+++ b/absl/time/civil_time.h
@@ -519,7 +519,7 @@ namespace time_internal {  // For functions found via ADL on civil-time tags.
 //
 // Example:
 //
-//   absl::CivilDay d = absl::CivilDay("1969-07-20");
+//   absl::CivilDay d = absl::CivilDay(1969, 7, 20);
 //   std::cout << "Date is: " << d << "\n";
 //
 std::ostream& operator<<(std::ostream& os, CivilYear y);
diff --git a/absl/time/duration.cc b/absl/time/duration.cc
index 9a8768113f31..f0b4631d6fa9 100644
--- a/absl/time/duration.cc
+++ b/absl/time/duration.cc
@@ -197,11 +197,11 @@ inline int64_t DecodeTwosComp(uint64_t v) { return absl::bit_cast<int64_t>(v); }
 // double as overflow cases.
 inline bool SafeAddRepHi(double a_hi, double b_hi, Duration* d) {
   double c = a_hi + b_hi;
-  if (c >= kint64max) {
+  if (c >= static_cast<double>(kint64max)) {
     *d = InfiniteDuration();
     return false;
   }
-  if (c <= kint64min) {
+  if (c <= static_cast<double>(kint64min)) {
     *d = -InfiniteDuration();
     return false;
   }
diff --git a/absl/time/time.h b/absl/time/time.h
index 0b7312ee983d..46ac26b3c0d2 100644
--- a/absl/time/time.h
+++ b/absl/time/time.h
@@ -422,7 +422,9 @@ Duration Milliseconds(T n) {
 template <typename T, time_internal::EnableIfFloat<T> = 0>
 Duration Seconds(T n) {
   if (n >= 0) {  // Note: `NaN >= 0` is false.
-    if (n >= (std::numeric_limits<int64_t>::max)()) return InfiniteDuration();
+    if (n >= static_cast<T>((std::numeric_limits<int64_t>::max)())) {
+      return InfiniteDuration();
+    }
     return time_internal::MakePosDoubleDuration(n);
   } else {
     if (std::isnan(n))
diff --git a/absl/types/any.h b/absl/types/any.h
index 507c8b2cc4f1..f79676949d3d 100644
--- a/absl/types/any.h
+++ b/absl/types/any.h
@@ -56,7 +56,7 @@
 #include "absl/base/config.h"
 #include "absl/utility/utility.h"
 
-#ifdef ABSL_HAVE_STD_ANY
+#ifdef ABSL_USES_STD_ANY
 
 #include <any>  // IWYU pragma: export
 
@@ -67,7 +67,7 @@ using std::bad_any_cast;
 using std::make_any;
 }  // namespace absl
 
-#else  // ABSL_HAVE_STD_ANY
+#else  // ABSL_USES_STD_ANY
 
 #include <algorithm>
 #include <cstddef>
@@ -538,6 +538,6 @@ T* any_cast(any* operand) noexcept {
 
 #undef ABSL_ANY_DETAIL_HAS_RTTI
 
-#endif  // ABSL_HAVE_STD_ANY
+#endif  // ABSL_USES_STD_ANY
 
 #endif  // ABSL_TYPES_ANY_H_
diff --git a/absl/types/any_exception_safety_test.cc b/absl/types/any_exception_safety_test.cc
index 17d7f5d77813..31c1140135f0 100644
--- a/absl/types/any_exception_safety_test.cc
+++ b/absl/types/any_exception_safety_test.cc
@@ -18,7 +18,7 @@
 
 // This test is a no-op when absl::any is an alias for std::any and when
 // exceptions are not enabled.
-#if !defined(ABSL_HAVE_STD_ANY) && defined(ABSL_HAVE_EXCEPTIONS)
+#if !defined(ABSL_USES_STD_ANY) && defined(ABSL_HAVE_EXCEPTIONS)
 
 #include <typeinfo>
 #include <vector>
@@ -170,4 +170,4 @@ TEST(AnyExceptionSafety, Emplace) {
 
 }  // namespace
 
-#endif  // #if !defined(ABSL_HAVE_STD_ANY) && defined(ABSL_HAVE_EXCEPTIONS)
+#endif  // #if !defined(ABSL_USES_STD_ANY) && defined(ABSL_HAVE_EXCEPTIONS)
diff --git a/absl/types/any_test.cc b/absl/types/any_test.cc
index 4a848ae4ae8f..70e4ba22b12b 100644
--- a/absl/types/any_test.cc
+++ b/absl/types/any_test.cc
@@ -15,7 +15,7 @@
 #include "absl/types/any.h"
 
 // This test is a no-op when absl::any is an alias for std::any.
-#if !defined(ABSL_HAVE_STD_ANY)
+#if !defined(ABSL_USES_STD_ANY)
 
 #include <initializer_list>
 #include <type_traits>
@@ -642,7 +642,7 @@ TEST(AnyTest, ConversionConstructionCausesOneCopy) {
 // Tests for Exception Behavior //
 //////////////////////////////////
 
-#if defined(ABSL_HAVE_STD_ANY)
+#if defined(ABSL_USES_STD_ANY)
 
 // If using a std `any` implementation, we can't check for a specific message.
 #define ABSL_ANY_TEST_EXPECT_BAD_ANY_CAST(...)                      \
@@ -656,7 +656,7 @@ TEST(AnyTest, ConversionConstructionCausesOneCopy) {
   ABSL_BASE_INTERNAL_EXPECT_FAIL((__VA_ARGS__), absl::bad_any_cast, \
                                  "Bad any cast")
 
-#endif  // defined(ABSL_HAVE_STD_ANY)
+#endif  // defined(ABSL_USES_STD_ANY)
 
 TEST(AnyTest, ThrowBadAlloc) {
   {
@@ -764,7 +764,7 @@ TEST(AnyTest, FailedEmplace) {
     BadCopyable bad;
     absl::any target(absl::in_place_type<int>);
     ABSL_ANY_TEST_EXPECT_BAD_COPY(target.emplace<BadCopyable>(bad));
-#if defined(ABSL_HAVE_STD_ANY) && defined(__GLIBCXX__)
+#if defined(ABSL_USES_STD_ANY) && defined(__GLIBCXX__)
     // libstdc++ std::any::emplace() implementation (as of 7.2) has a bug: if an
     // exception is thrown, *this contains a value.
 #define ABSL_GLIBCXX_ANY_EMPLACE_EXCEPTION_BUG 1
@@ -778,4 +778,4 @@ TEST(AnyTest, FailedEmplace) {
 
 }  // namespace
 
-#endif  // #if !defined(ABSL_HAVE_STD_ANY)
+#endif  // #if !defined(ABSL_USES_STD_ANY)
diff --git a/absl/types/bad_any_cast.cc b/absl/types/bad_any_cast.cc
index 505919a55831..2a5381266452 100644
--- a/absl/types/bad_any_cast.cc
+++ b/absl/types/bad_any_cast.cc
@@ -14,7 +14,7 @@
 
 #include "absl/types/bad_any_cast.h"
 
-#ifndef ABSL_HAVE_STD_ANY
+#ifndef ABSL_USES_STD_ANY
 
 #include <cstdlib>
 
@@ -41,4 +41,4 @@ void ThrowBadAnyCast() {
 }  // namespace any_internal
 }  // namespace absl
 
-#endif  // ABSL_HAVE_STD_ANY
+#endif  // ABSL_USES_STD_ANY
diff --git a/absl/types/bad_any_cast.h b/absl/types/bad_any_cast.h
index 8d020ede466b..6a53c0108100 100644
--- a/absl/types/bad_any_cast.h
+++ b/absl/types/bad_any_cast.h
@@ -25,7 +25,7 @@
 
 #include "absl/base/config.h"
 
-#ifdef ABSL_HAVE_STD_ANY
+#ifdef ABSL_USES_STD_ANY
 
 #include <any>
 
@@ -33,7 +33,7 @@ namespace absl {
 using std::bad_any_cast;
 }  // namespace absl
 
-#else  // ABSL_HAVE_STD_ANY
+#else  // ABSL_USES_STD_ANY
 
 namespace absl {
 
@@ -66,6 +66,6 @@ namespace any_internal {
 }  // namespace any_internal
 }  // namespace absl
 
-#endif  // ABSL_HAVE_STD_ANY
+#endif  // ABSL_USES_STD_ANY
 
 #endif  // ABSL_TYPES_BAD_ANY_CAST_H_
diff --git a/absl/types/bad_optional_access.cc b/absl/types/bad_optional_access.cc
index a791c7c21da8..d9ec21bf42b9 100644
--- a/absl/types/bad_optional_access.cc
+++ b/absl/types/bad_optional_access.cc
@@ -14,7 +14,7 @@
 
 #include "absl/types/bad_optional_access.h"
 
-#ifndef ABSL_HAVE_STD_OPTIONAL
+#ifndef ABSL_USES_STD_OPTIONAL
 
 #include <cstdlib>
 
@@ -43,4 +43,4 @@ void throw_bad_optional_access() {
 }  // namespace optional_internal
 }  // namespace absl
 
-#endif  // ABSL_HAVE_STD_OPTIONAL
+#endif  // ABSL_USES_STD_OPTIONAL
diff --git a/absl/types/bad_optional_access.h b/absl/types/bad_optional_access.h
index add5c452cd50..32dd6a91ea65 100644
--- a/absl/types/bad_optional_access.h
+++ b/absl/types/bad_optional_access.h
@@ -25,7 +25,7 @@
 
 #include "absl/base/config.h"
 
-#ifdef ABSL_HAVE_STD_OPTIONAL
+#ifdef ABSL_USES_STD_OPTIONAL
 
 #include <optional>
 
@@ -33,7 +33,7 @@ namespace absl {
 using std::bad_optional_access;
 }  // namespace absl
 
-#else  // ABSL_HAVE_STD_OPTIONAL
+#else  // ABSL_USES_STD_OPTIONAL
 
 namespace absl {
 
@@ -69,6 +69,6 @@ namespace optional_internal {
 }  // namespace optional_internal
 }  // namespace absl
 
-#endif  // ABSL_HAVE_STD_OPTIONAL
+#endif  // ABSL_USES_STD_OPTIONAL
 
 #endif  // ABSL_TYPES_BAD_OPTIONAL_ACCESS_H_
diff --git a/absl/types/bad_variant_access.cc b/absl/types/bad_variant_access.cc
index a4325c8df7db..dbaea9e9d1db 100644
--- a/absl/types/bad_variant_access.cc
+++ b/absl/types/bad_variant_access.cc
@@ -14,7 +14,7 @@
 
 #include "absl/types/bad_variant_access.h"
 
-#ifndef ABSL_HAVE_STD_VARIANT
+#ifndef ABSL_USES_STD_VARIANT
 
 #include <cstdlib>
 #include <stdexcept>
@@ -59,4 +59,4 @@ void Rethrow() {
 }  // namespace variant_internal
 }  // namespace absl
 
-#endif  // ABSL_HAVE_STD_VARIANT
+#endif  // ABSL_USES_STD_VARIANT
diff --git a/absl/types/bad_variant_access.h b/absl/types/bad_variant_access.h
index 637db4355053..6935d01b99f7 100644
--- a/absl/types/bad_variant_access.h
+++ b/absl/types/bad_variant_access.h
@@ -25,7 +25,7 @@
 
 #include "absl/base/config.h"
 
-#ifdef ABSL_HAVE_STD_VARIANT
+#ifdef ABSL_USES_STD_VARIANT
 
 #include <variant>
 
@@ -33,7 +33,7 @@ namespace absl {
 using std::bad_variant_access;
 }  // namespace absl
 
-#else  // ABSL_HAVE_STD_VARIANT
+#else  // ABSL_USES_STD_VARIANT
 
 namespace absl {
 
@@ -73,6 +73,6 @@ namespace variant_internal {
 }  // namespace variant_internal
 }  // namespace absl
 
-#endif  // ABSL_HAVE_STD_VARIANT
+#endif  // ABSL_USES_STD_VARIANT
 
 #endif  // ABSL_TYPES_BAD_VARIANT_ACCESS_H_
diff --git a/absl/types/internal/variant.h b/absl/types/internal/variant.h
index 19de2e137593..58b385921f59 100644
--- a/absl/types/internal/variant.h
+++ b/absl/types/internal/variant.h
@@ -37,7 +37,7 @@
 #include "absl/types/bad_variant_access.h"
 #include "absl/utility/utility.h"
 
-#if !defined(ABSL_HAVE_STD_VARIANT)
+#if !defined(ABSL_USES_STD_VARIANT)
 
 namespace absl {
 
@@ -1640,5 +1640,5 @@ struct VariantHashBase<Variant,
 }  // namespace variant_internal
 }  // namespace absl
 
-#endif  // !defined(ABSL_HAVE_STD_VARIANT)
+#endif  // !defined(ABSL_USES_STD_VARIANT)
 #endif  // ABSL_TYPES_variant_internal_H_
diff --git a/absl/types/optional.h b/absl/types/optional.h
index ed8faf97a1d4..14032598d9b0 100644
--- a/absl/types/optional.h
+++ b/absl/types/optional.h
@@ -38,7 +38,7 @@
 #include "absl/base/config.h"   // TODO(calabrese) IWYU removal?
 #include "absl/utility/utility.h"
 
-#ifdef ABSL_HAVE_STD_OPTIONAL
+#ifdef ABSL_USES_STD_OPTIONAL
 
 #include <optional>  // IWYU pragma: export
 
@@ -50,7 +50,7 @@ using std::nullopt_t;
 using std::nullopt;
 }  // namespace absl
 
-#else  // ABSL_HAVE_STD_OPTIONAL
+#else  // ABSL_USES_STD_OPTIONAL
 
 #include <cassert>
 #include <functional>
@@ -767,6 +767,6 @@ struct hash<absl::optional<T> >
 
 #undef ABSL_MSVC_CONSTEXPR_BUG_IN_UNION_LIKE_CLASS
 
-#endif  // ABSL_HAVE_STD_OPTIONAL
+#endif  // ABSL_USES_STD_OPTIONAL
 
 #endif  // ABSL_TYPES_OPTIONAL_H_
diff --git a/absl/types/optional_exception_safety_test.cc b/absl/types/optional_exception_safety_test.cc
index f99e35c05447..0f7fae6cb4cf 100644
--- a/absl/types/optional_exception_safety_test.cc
+++ b/absl/types/optional_exception_safety_test.cc
@@ -18,7 +18,7 @@
 
 // This test is a no-op when absl::optional is an alias for std::optional and
 // when exceptions are not enabled.
-#if !defined(ABSL_HAVE_STD_OPTIONAL) && defined(ABSL_HAVE_EXCEPTIONS)
+#if !defined(ABSL_USES_STD_OPTIONAL) && defined(ABSL_HAVE_EXCEPTIONS)
 
 #include "gtest/gtest.h"
 #include "absl/base/internal/exception_safety_testing.h"
@@ -287,4 +287,4 @@ TEST(OptionalExceptionSafety, NothrowMoveAssign) {
 
 }  // namespace absl
 
-#endif  // #if !defined(ABSL_HAVE_STD_OPTIONAL) && defined(ABSL_HAVE_EXCEPTIONS)
+#endif  // #if !defined(ABSL_USES_STD_OPTIONAL) && defined(ABSL_HAVE_EXCEPTIONS)
diff --git a/absl/types/optional_test.cc b/absl/types/optional_test.cc
index 35efa8635077..47d5c8a29e00 100644
--- a/absl/types/optional_test.cc
+++ b/absl/types/optional_test.cc
@@ -15,7 +15,7 @@
 #include "absl/types/optional.h"
 
 // This test is a no-op when absl::optional is an alias for std::optional.
-#if !defined(ABSL_HAVE_STD_OPTIONAL)
+#if !defined(ABSL_USES_STD_OPTIONAL)
 
 #include <string>
 #include <type_traits>
@@ -224,7 +224,7 @@ TEST(optionalTest, CopyConstructor) {
 
   EXPECT_FALSE(
       absl::is_trivially_copy_constructible<absl::optional<Copyable>>::value);
-#if defined(ABSL_HAVE_STD_OPTIONAL) && defined(__GLIBCXX__)
+#if defined(ABSL_USES_STD_OPTIONAL) && defined(__GLIBCXX__)
   // libstdc++ std::optional implementation (as of 7.2) has a bug: when T is
   // trivially copyable, optional<T> is not trivially copyable (due to one of
   // its base class is unconditionally nontrivial).
@@ -279,7 +279,7 @@ TEST(optionalTest, CopyConstructor) {
     // std::optional when T is volatile-qualified. So skipping this test.
     // Bug report:
     // https://connect.microsoft.com/VisualStudio/feedback/details/3142534
-#if defined(ABSL_HAVE_STD_OPTIONAL) && defined(_MSC_VER) && _MSC_VER >= 1911
+#if defined(ABSL_USES_STD_OPTIONAL) && defined(_MSC_VER) && _MSC_VER >= 1911
 #define ABSL_MSVC_OPTIONAL_VOLATILE_COPY_BUG 1
 #endif
 #ifndef ABSL_MSVC_OPTIONAL_VOLATILE_COPY_BUG
@@ -305,7 +305,7 @@ TEST(optionalTest, MoveConstructor) {
   EXPECT_FALSE(std::is_move_constructible<absl::optional<NonMovable>>::value);
   // test noexcept
   EXPECT_TRUE(std::is_nothrow_move_constructible<absl::optional<int>>::value);
-#ifndef ABSL_HAVE_STD_OPTIONAL
+#ifndef ABSL_USES_STD_OPTIONAL
   EXPECT_EQ(
       absl::default_allocator_is_nothrow::value,
       std::is_nothrow_move_constructible<absl::optional<MoveableThrow>>::value);
@@ -639,7 +639,7 @@ TEST(optionalTest, CopyAssignment) {
   EXPECT_FALSE(absl::is_trivially_copy_assignable<NonTrivial>::value);
 
   // std::optional doesn't support volatile nontrivial types.
-#ifndef ABSL_HAVE_STD_OPTIONAL
+#ifndef ABSL_USES_STD_OPTIONAL
   {
     StructorListener listener;
     Listenable::listener = &listener;
@@ -658,7 +658,7 @@ TEST(optionalTest, CopyAssignment) {
     EXPECT_EQ(1, listener.destruct);
     EXPECT_EQ(1, listener.volatile_copy_assign);
   }
-#endif  // ABSL_HAVE_STD_OPTIONAL
+#endif  // ABSL_USES_STD_OPTIONAL
 }
 
 TEST(optionalTest, MoveAssignment) {
@@ -682,7 +682,7 @@ TEST(optionalTest, MoveAssignment) {
     EXPECT_EQ(1, listener.move_assign);
   }
   // std::optional doesn't support volatile nontrivial types.
-#ifndef ABSL_HAVE_STD_OPTIONAL
+#ifndef ABSL_USES_STD_OPTIONAL
   {
     StructorListener listener;
     Listenable::listener = &listener;
@@ -702,7 +702,7 @@ TEST(optionalTest, MoveAssignment) {
     EXPECT_EQ(1, listener.destruct);
     EXPECT_EQ(1, listener.volatile_move_assign);
   }
-#endif  // ABSL_HAVE_STD_OPTIONAL
+#endif  // ABSL_USES_STD_OPTIONAL
   EXPECT_FALSE(absl::is_move_assignable<absl::optional<const int>>::value);
   EXPECT_TRUE(absl::is_move_assignable<absl::optional<Copyable>>::value);
   EXPECT_TRUE(absl::is_move_assignable<absl::optional<MoveableThrow>>::value);
@@ -1560,7 +1560,7 @@ TEST(optionalTest, NoExcept) {
   static_assert(
       std::is_nothrow_move_constructible<absl::optional<MoveMeNoThrow>>::value,
       "");
-#ifndef ABSL_HAVE_STD_OPTIONAL
+#ifndef ABSL_USES_STD_OPTIONAL
   static_assert(absl::default_allocator_is_nothrow::value ==
                     std::is_nothrow_move_constructible<
                         absl::optional<MoveMeThrow>>::value,
@@ -1658,4 +1658,4 @@ TEST(optionalTest, InPlaceTSFINAEBug) {
 
 }  // namespace
 
-#endif  // #if !defined(ABSL_HAVE_STD_OPTIONAL)
+#endif  // #if !defined(ABSL_USES_STD_OPTIONAL)
diff --git a/absl/types/variant.h b/absl/types/variant.h
index 7ef7f88ca110..f3558703a82a 100644
--- a/absl/types/variant.h
+++ b/absl/types/variant.h
@@ -45,7 +45,7 @@
 #include "absl/base/config.h"
 #include "absl/utility/utility.h"
 
-#ifdef ABSL_HAVE_STD_VARIANT
+#ifdef ABSL_USES_STD_VARIANT
 
 #include <variant>  // IWYU pragma: export
 
@@ -64,7 +64,7 @@ using std::variant_size_v;
 using std::visit;
 }  // namespace absl
 
-#else  // ABSL_HAVE_STD_VARIANT
+#else  // ABSL_USES_STD_VARIANT
 
 #include <functional>
 #include <new>
@@ -812,7 +812,7 @@ struct hash<absl::variant<T...>>
 
 }  // namespace std
 
-#endif  // ABSL_HAVE_STD_VARIANT
+#endif  // ABSL_USES_STD_VARIANT
 
 namespace absl {
 namespace variant_internal {
diff --git a/absl/types/variant_exception_safety_test.cc b/absl/types/variant_exception_safety_test.cc
index fd7e6c7fe802..b486a71e5b72 100644
--- a/absl/types/variant_exception_safety_test.cc
+++ b/absl/types/variant_exception_safety_test.cc
@@ -18,7 +18,7 @@
 
 // This test is a no-op when absl::variant is an alias for std::variant and when
 // exceptions are not enabled.
-#if !defined(ABSL_HAVE_STD_VARIANT) && defined(ABSL_HAVE_EXCEPTIONS)
+#if !defined(ABSL_USES_STD_VARIANT) && defined(ABSL_HAVE_EXCEPTIONS)
 
 #include <iostream>
 #include <memory>
@@ -237,7 +237,7 @@ TEST(VariantExceptionSafetyTest, CopyAssign) {
   }
   // libstdc++ std::variant has bugs on copy assignment regarding exception
   // safety.
-#if !(defined(ABSL_HAVE_STD_VARIANT) && defined(__GLIBCXX__))
+#if !(defined(ABSL_USES_STD_VARIANT) && defined(__GLIBCXX__))
   // index() != j
   // if is_nothrow_copy_constructible_v<Tj> or
   // !is_nothrow_move_constructible<Tj> is true, equivalent to
@@ -268,7 +268,7 @@ TEST(VariantExceptionSafetyTest, CopyAssign) {
                     .Test());
     EXPECT_FALSE(tester.WithContracts(strong_guarantee).Test());
   }
-#endif  // !(defined(ABSL_HAVE_STD_VARIANT) && defined(__GLIBCXX__))
+#endif  // !(defined(ABSL_USES_STD_VARIANT) && defined(__GLIBCXX__))
   {
     // is_nothrow_copy_constructible_v<Tj> == false &&
     // is_nothrow_move_constructible_v<Tj> == true
@@ -325,7 +325,7 @@ TEST(VariantExceptionSafetyTest, MoveAssign) {
     // The fix is targeted for gcc-9.
     // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87431#c7
     // https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=267614
-#if !(defined(ABSL_HAVE_STD_VARIANT) && \
+#if !(defined(ABSL_USES_STD_VARIANT) && \
       defined(_GLIBCXX_RELEASE) && _GLIBCXX_RELEASE == 8)
     // - otherwise (index() != j), equivalent to
     // emplace<j>(get<j>(std::move(rhs)))
@@ -342,7 +342,7 @@ TEST(VariantExceptionSafetyTest, MoveAssign) {
                       auto copy = rhs;
                       *lhs = std::move(copy);
                     }));
-#endif  // !(defined(ABSL_HAVE_STD_VARIANT) &&
+#endif  // !(defined(ABSL_USES_STD_VARIANT) &&
         //   defined(_GLIBCXX_RELEASE) && _GLIBCXX_RELEASE == 8)
   }
 }
@@ -445,7 +445,7 @@ TEST(VariantExceptionSafetyTest, ValueAssign) {
   // and operator=(variant&&) invokes Tj's move ctor which doesn't throw.
   // libstdc++ std::variant has bugs on conversion assignment regarding
   // exception safety.
-#if !(defined(ABSL_HAVE_STD_VARIANT) && defined(__GLIBCXX__))
+#if !(defined(ABSL_USES_STD_VARIANT) && defined(__GLIBCXX__))
   {
     MoveNothrow rhs;
     EXPECT_TRUE(MakeExceptionSafetyTester()
@@ -453,7 +453,7 @@ TEST(VariantExceptionSafetyTest, ValueAssign) {
                     .WithContracts(VariantInvariants, strong_guarantee)
                     .Test([&rhs](ThrowingVariant* lhs) { *lhs = rhs; }));
   }
-#endif  // !(defined(ABSL_HAVE_STD_VARIANT) && defined(__GLIBCXX__))
+#endif  // !(defined(ABSL_USES_STD_VARIANT) && defined(__GLIBCXX__))
 }
 
 TEST(VariantExceptionSafetyTest, Emplace) {
@@ -527,4 +527,4 @@ TEST(VariantExceptionSafetyTest, Swap) {
 
 #endif  // !defined(ABSL_INTERNAL_MSVC_2017_DBG_MODE)
 
-#endif  // #if !defined(ABSL_HAVE_STD_VARIANT) && defined(ABSL_HAVE_EXCEPTIONS)
+#endif  // #if !defined(ABSL_USES_STD_VARIANT) && defined(ABSL_HAVE_EXCEPTIONS)
diff --git a/absl/types/variant_test.cc b/absl/types/variant_test.cc
index b59127457148..2913775a4e59 100644
--- a/absl/types/variant_test.cc
+++ b/absl/types/variant_test.cc
@@ -20,7 +20,7 @@
 #include "absl/types/variant.h"
 
 // This test is a no-op when absl::variant is an alias for std::variant.
-#if !defined(ABSL_HAVE_STD_VARIANT)
+#if !defined(ABSL_USES_STD_VARIANT)
 
 #include <algorithm>
 #include <cstddef>
@@ -842,7 +842,7 @@ TEST(VariantTest, TestBackupAssign) {
   }
 
   // libstdc++ doesn't pass this test
-#if !(defined(ABSL_HAVE_STD_VARIANT) && defined(__GLIBCXX__))
+#if !(defined(ABSL_USES_STD_VARIANT) && defined(__GLIBCXX__))
   EXPECT_EQ(3, counter[0]);
   EXPECT_EQ(2, counter[1]);
   EXPECT_EQ(2, counter[2]);
@@ -1933,7 +1933,7 @@ TEST(VariantTest, VisitReferenceWrapper) {
 }
 
 // libstdc++ std::variant doesn't support the INVOKE semantics.
-#if !(defined(ABSL_HAVE_STD_VARIANT) && defined(__GLIBCXX__))
+#if !(defined(ABSL_USES_STD_VARIANT) && defined(__GLIBCXX__))
 TEST(VariantTest, VisitMemberFunction) {
   absl::variant<std::unique_ptr<Class>> p(absl::make_unique<Class>());
   absl::variant<std::unique_ptr<const Class>> cp(
@@ -1957,7 +1957,7 @@ TEST(VariantTest, VisitDataMember) {
 
   EXPECT_EQ(42, absl::visit(&Class::member, cp));
 }
-#endif  // !(defined(ABSL_HAVE_STD_VARIANT) && defined(__GLIBCXX__))
+#endif  // !(defined(ABSL_USES_STD_VARIANT) && defined(__GLIBCXX__))
 
 /////////////////////////
 // [variant.monostate] //
@@ -2035,7 +2035,7 @@ TEST(VariantTest, NonmemberSwap) {
   std::swap(a, b);
   EXPECT_THAT(a, VariantWith<SpecialSwap>(v2));
   EXPECT_THAT(b, VariantWith<SpecialSwap>(v1));
-#ifndef ABSL_HAVE_STD_VARIANT
+#ifndef ABSL_USES_STD_VARIANT
   EXPECT_FALSE(absl::get<SpecialSwap>(a).special_swap);
 #endif
 
@@ -2083,7 +2083,7 @@ TEST(VariantTest, Hash) {
 
 // MSVC std::hash<std::variant> does not use the index, thus produce the same
 // result on the same value as different alternative.
-#if !(defined(_MSC_VER) && defined(ABSL_HAVE_STD_VARIANT))
+#if !(defined(_MSC_VER) && defined(ABSL_USES_STD_VARIANT))
   {
     // same value as different alternative
     variant<int, int> v0(in_place_index<0>, 42);
@@ -2091,7 +2091,7 @@ TEST(VariantTest, Hash) {
     std::hash<variant<int, int>> hash;
     EXPECT_NE(hash(v0), hash(v1));
   }
-#endif  // !(defined(_MSC_VER) && defined(ABSL_HAVE_STD_VARIANT))
+#endif  // !(defined(_MSC_VER) && defined(ABSL_USES_STD_VARIANT))
 
   {
     std::hash<variant<int>> hash;
@@ -2118,7 +2118,7 @@ TEST(VariantTest, Hash) {
 ////////////////////////////////////////
 
 // Test that a set requiring a basic type conversion works correctly
-#if !defined(ABSL_HAVE_STD_VARIANT)
+#if !defined(ABSL_USES_STD_VARIANT)
 TEST(VariantTest, TestConvertingSet) {
   typedef variant<double> Variant;
   Variant v(1.0);
@@ -2128,7 +2128,7 @@ TEST(VariantTest, TestConvertingSet) {
   ASSERT_TRUE(nullptr != absl::get_if<double>(&v));
   EXPECT_DOUBLE_EQ(2, absl::get<double>(v));
 }
-#endif  // ABSL_HAVE_STD_VARIANT
+#endif  // ABSL_USES_STD_VARIANT
 
 // Test that a vector of variants behaves reasonably.
 TEST(VariantTest, Container) {
@@ -2280,7 +2280,7 @@ struct Convertible2 {
 };
 
 TEST(VariantTest, TestRvalueConversion) {
-#if !defined(ABSL_HAVE_STD_VARIANT)
+#if !defined(ABSL_USES_STD_VARIANT)
   variant<double, std::string> var(
       ConvertVariantTo<variant<double, std::string>>(
           variant<std::string, int>(0)));
@@ -2313,7 +2313,7 @@ TEST(VariantTest, TestRvalueConversion) {
   variant2 = ConvertVariantTo<variant<int32_t, uint32_t>>(variant<uint32_t>(42));
   ASSERT_TRUE(absl::holds_alternative<uint32_t>(variant2));
   EXPECT_EQ(42, absl::get<uint32_t>(variant2));
-#endif  // !ABSL_HAVE_STD_VARIANT
+#endif  // !ABSL_USES_STD_VARIANT
 
   variant<Convertible1, Convertible2> variant3(
       ConvertVariantTo<variant<Convertible1, Convertible2>>(
@@ -2326,7 +2326,7 @@ TEST(VariantTest, TestRvalueConversion) {
 }
 
 TEST(VariantTest, TestLvalueConversion) {
-#if !defined(ABSL_HAVE_STD_VARIANT)
+#if !defined(ABSL_USES_STD_VARIANT)
   variant<std::string, int> source1 = 0;
   variant<double, std::string> destination(
       ConvertVariantTo<variant<double, std::string>>(source1));
@@ -2428,7 +2428,7 @@ TEST(VariantTest, DoesNotMoveFromLvalues) {
 }
 
 TEST(VariantTest, TestRvalueConversionViaConvertVariantTo) {
-#if !defined(ABSL_HAVE_STD_VARIANT)
+#if !defined(ABSL_USES_STD_VARIANT)
   variant<double, std::string> var(
       ConvertVariantTo<variant<double, std::string>>(
           variant<std::string, int>(3)));
@@ -2467,7 +2467,7 @@ TEST(VariantTest, TestRvalueConversionViaConvertVariantTo) {
 }
 
 TEST(VariantTest, TestLvalueConversionViaConvertVariantTo) {
-#if !defined(ABSL_HAVE_STD_VARIANT)
+#if !defined(ABSL_USES_STD_VARIANT)
   variant<std::string, int> source1 = 3;
   variant<double, std::string> destination(
       ConvertVariantTo<variant<double, std::string>>(source1));
@@ -2499,7 +2499,7 @@ TEST(VariantTest, TestLvalueConversionViaConvertVariantTo) {
   variant<uint32_t> source6(42);
   variant2 = ConvertVariantTo<variant<int32_t, uint32_t>>(source6);
   EXPECT_THAT(absl::get_if<uint32_t>(&variant2), Pointee(42));
-#endif  // !ABSL_HAVE_STD_VARIANT
+#endif  // !ABSL_USES_STD_VARIANT
 
   variant<Convertible2, Convertible1> source7((Convertible1()));
   variant<Convertible1, Convertible2> variant3(
@@ -2533,7 +2533,7 @@ TEST(VariantTest, TestMoveConversionViaConvertVariantTo) {
 // standard and we know that libstdc++ variant doesn't have this feature.
 // For more details see the paper:
 // http://open-std.org/JTC1/SC22/WG21/docs/papers/2017/p0602r0.html
-#if !(defined(ABSL_HAVE_STD_VARIANT) && defined(__GLIBCXX__))
+#if !(defined(ABSL_USES_STD_VARIANT) && defined(__GLIBCXX__))
 #define ABSL_VARIANT_PROPAGATE_COPY_MOVE_TRIVIALITY 1
 #endif
 
@@ -2711,4 +2711,4 @@ TEST(VariantTest, MoveCtorBug) {
 }  // namespace
 }  // namespace absl
 
-#endif  // #if !defined(ABSL_HAVE_STD_VARIANT)
+#endif  // #if !defined(ABSL_USES_STD_VARIANT)
diff --git a/absl/utility/utility.h b/absl/utility/utility.h
index eef8fb41fe8e..5a98c2c39c41 100644
--- a/absl/utility/utility.h
+++ b/absl/utility/utility.h
@@ -158,12 +158,12 @@ using index_sequence_for = make_index_sequence<sizeof...(Ts)>;
 
 // Tag types
 
-#ifdef ABSL_HAVE_STD_OPTIONAL
+#ifdef ABSL_USES_STD_OPTIONAL
 
 using std::in_place_t;
 using std::in_place;
 
-#else  // ABSL_HAVE_STD_OPTIONAL
+#else  // ABSL_USES_STD_OPTIONAL
 
 // in_place_t
 //
@@ -174,9 +174,9 @@ struct in_place_t {};
 
 ABSL_INTERNAL_INLINE_CONSTEXPR(in_place_t, in_place, {});
 
-#endif  // ABSL_HAVE_STD_OPTIONAL
+#endif  // ABSL_USES_STD_OPTIONAL
 
-#if defined(ABSL_HAVE_STD_ANY) || defined(ABSL_HAVE_STD_VARIANT)
+#if defined(ABSL_USES_STD_ANY) || defined(ABSL_USES_STD_VARIANT)
 using std::in_place_type;
 using std::in_place_type_t;
 #else
@@ -191,9 +191,9 @@ using in_place_type_t = void (*)(utility_internal::InPlaceTypeTag<T>);
 
 template <typename T>
 void in_place_type(utility_internal::InPlaceTypeTag<T>) {}
-#endif  // ABSL_HAVE_STD_ANY || ABSL_HAVE_STD_VARIANT
+#endif  // ABSL_USES_STD_ANY || ABSL_USES_STD_VARIANT
 
-#ifdef ABSL_HAVE_STD_VARIANT
+#ifdef ABSL_USES_STD_VARIANT
 using std::in_place_index;
 using std::in_place_index_t;
 #else
@@ -208,7 +208,7 @@ using in_place_index_t = void (*)(utility_internal::InPlaceIndexTag<I>);
 
 template <size_t I>
 void in_place_index(utility_internal::InPlaceIndexTag<I>) {}
-#endif  // ABSL_HAVE_STD_VARIANT
+#endif  // ABSL_USES_STD_VARIANT
 
 // Constexpr move and forward