diff --git a/CMake/AbseilDll.cmake b/CMake/AbseilDll.cmake
index 94515b83..48900c20 100644
--- a/CMake/AbseilDll.cmake
+++ b/CMake/AbseilDll.cmake
@@ -200,7 +200,6 @@ set(ABSL_INTERNAL_DLL_FILES
   "log/initialize.cc"
   "log/initialize.h"
   "log/log.h"
-  "log/log_entry.cc"
   "log/log_entry.h"
   "log/log_sink.cc"
   "log/log_sink.h"
@@ -285,7 +284,6 @@ set(ABSL_INTERNAL_DLL_FILES
   "strings/cord.h"
   "strings/cord_analysis.cc"
   "strings/cord_analysis.h"
-  "strings/cord_buffer.cc"
   "strings/cord_buffer.h"
   "strings/escaping.cc"
   "strings/escaping.h"
diff --git a/absl/base/config.h b/absl/base/config.h
index 5e437cde..5256d5b5 100644
--- a/absl/base/config.h
+++ b/absl/base/config.h
@@ -821,29 +821,6 @@ static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 #define ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION 1
 #endif
 
-// ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-//
-// Prior to C++17, static constexpr variables defined in classes required a
-// separate definition outside of the class body, for example:
-//
-// class Foo {
-//   static constexpr int kBar = 0;
-// };
-// constexpr int Foo::kBar;
-//
-// In C++17, these variables defined in classes are considered inline variables,
-// and the extra declaration is redundant. Since some compilers warn on the
-// extra declarations, ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL can be used
-// conditionally ignore them:
-//
-// #ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-// constexpr int Foo::kBar;
-// #endif
-#if defined(ABSL_INTERNAL_CPLUSPLUS_LANG) && \
-    ABSL_INTERNAL_CPLUSPLUS_LANG < 201703L
-#define ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL 1
-#endif
-
 // `ABSL_INTERNAL_HAS_RTTI` determines whether abseil is being compiled with
 // RTTI support.
 #ifdef ABSL_INTERNAL_HAS_RTTI
diff --git a/absl/base/exception_safety_testing_test.cc b/absl/base/exception_safety_testing_test.cc
index bf5aa7cf..55a6fe1a 100644
--- a/absl/base/exception_safety_testing_test.cc
+++ b/absl/base/exception_safety_testing_test.cc
@@ -705,10 +705,6 @@ struct BasicGuaranteeWithExtraContracts : public NonNegative {
   static constexpr int kExceptionSentinel = 9999;
 };
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr int BasicGuaranteeWithExtraContracts::kExceptionSentinel;
-#endif
-
 TEST(ExceptionCheckTest, BasicGuaranteeWithExtraContracts) {
   auto tester_with_val =
       tester.WithInitialValue(BasicGuaranteeWithExtraContracts{});
diff --git a/absl/base/internal/cycleclock.cc b/absl/base/internal/cycleclock.cc
index 902e3f5e..99466015 100644
--- a/absl/base/internal/cycleclock.cc
+++ b/absl/base/internal/cycleclock.cc
@@ -35,11 +35,6 @@ namespace base_internal {
 
 #if ABSL_USE_UNSCALED_CYCLECLOCK
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr int32_t CycleClock::kShift;
-constexpr double CycleClock::kFrequencyScale;
-#endif
-
 ABSL_CONST_INIT std::atomic<CycleClockSourceFunc>
     CycleClock::cycle_clock_source_{nullptr};
 
diff --git a/absl/base/internal/fast_type_id.h b/absl/base/internal/fast_type_id.h
index a547b3a8..36372f52 100644
--- a/absl/base/internal/fast_type_id.h
+++ b/absl/base/internal/fast_type_id.h
@@ -28,11 +28,6 @@ struct FastTypeTag {
   constexpr static char dummy_var = 0;
 };
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-template <typename Type>
-constexpr char FastTypeTag<Type>::dummy_var;
-#endif
-
 // FastTypeId<Type>() evaluates at compile/link-time to a unique pointer for the
 // passed-in type. These are meant to be good match for keys into maps or
 // straight up comparisons.
diff --git a/absl/base/internal/spinlock.cc b/absl/base/internal/spinlock.cc
index 381b913b..430f775b 100644
--- a/absl/base/internal/spinlock.cc
+++ b/absl/base/internal/spinlock.cc
@@ -67,15 +67,6 @@ void RegisterSpinLockProfiler(void (*fn)(const void *contendedlock,
   submit_profile_data.Store(fn);
 }
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-// Static member variable definitions.
-constexpr uint32_t SpinLock::kSpinLockHeld;
-constexpr uint32_t SpinLock::kSpinLockCooperative;
-constexpr uint32_t SpinLock::kSpinLockDisabledScheduling;
-constexpr uint32_t SpinLock::kSpinLockSleeper;
-constexpr uint32_t SpinLock::kWaitTimeMask;
-#endif
-
 // Uncommon constructors.
 SpinLock::SpinLock(base_internal::SchedulingMode mode)
     : lockword_(IsCooperative(mode) ? kSpinLockCooperative : 0) {
diff --git a/absl/container/fixed_array.h b/absl/container/fixed_array.h
index 94042059..b213eb13 100644
--- a/absl/container/fixed_array.h
+++ b/absl/container/fixed_array.h
@@ -517,15 +517,6 @@ class ABSL_ATTRIBUTE_WARN_UNUSED FixedArray {
   Storage storage_;
 };
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-template <typename T, size_t N, typename A>
-constexpr size_t FixedArray<T, N, A>::kInlineBytesDefault;
-
-template <typename T, size_t N, typename A>
-constexpr typename FixedArray<T, N, A>::size_type
-    FixedArray<T, N, A>::inline_elements;
-#endif
-
 template <typename T, size_t N, typename A>
 void FixedArray<T, N, A>::NonEmptyInlinedStorage::AnnotateConstruct(
     typename FixedArray<T, N, A>::size_type n) {
diff --git a/absl/container/internal/hashtablez_sampler.cc b/absl/container/internal/hashtablez_sampler.cc
index ad5a493c..c0fce879 100644
--- a/absl/container/internal/hashtablez_sampler.cc
+++ b/absl/container/internal/hashtablez_sampler.cc
@@ -42,10 +42,6 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 namespace container_internal {
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr int HashtablezInfo::kMaxStackDepth;
-#endif
-
 namespace {
 ABSL_CONST_INIT std::atomic<bool> g_hashtablez_enabled{
     false
diff --git a/absl/container/internal/raw_hash_set.cc b/absl/container/internal/raw_hash_set.cc
index 03a3b69f..b58484e0 100644
--- a/absl/container/internal/raw_hash_set.cc
+++ b/absl/container/internal/raw_hash_set.cc
@@ -66,10 +66,6 @@ ABSL_CONST_INIT ABSL_DLL const ctrl_t kSooControl[17] = {
 static_assert(NumControlBytes(SooCapacity()) <= 17,
               "kSooControl capacity too small");
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr size_t Group::kWidth;
-#endif
-
 namespace {
 
 // Returns "random" seed.
diff --git a/absl/crc/internal/crc_x86_arm_combined.cc b/absl/crc/internal/crc_x86_arm_combined.cc
index a722f655..9817c73c 100644
--- a/absl/crc/internal/crc_x86_arm_combined.cc
+++ b/absl/crc/internal/crc_x86_arm_combined.cc
@@ -345,24 +345,6 @@ class CRC32AcceleratedX86ARMCombinedMultipleStreamsBase
   static constexpr size_t kMaxStreams = 3;
 };
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-alignas(16) constexpr uint64_t
-    CRC32AcceleratedX86ARMCombinedMultipleStreamsBase::k1k2[2];
-alignas(16) constexpr uint64_t
-    CRC32AcceleratedX86ARMCombinedMultipleStreamsBase::k3k4[2];
-alignas(16) constexpr uint64_t
-    CRC32AcceleratedX86ARMCombinedMultipleStreamsBase::k5k6[2];
-alignas(16) constexpr uint64_t
-    CRC32AcceleratedX86ARMCombinedMultipleStreamsBase::k7k0[2];
-alignas(16) constexpr uint64_t
-    CRC32AcceleratedX86ARMCombinedMultipleStreamsBase::kPoly[2];
-alignas(16) constexpr uint32_t
-    CRC32AcceleratedX86ARMCombinedMultipleStreamsBase::kMask[4];
-constexpr size_t
-    CRC32AcceleratedX86ARMCombinedMultipleStreamsBase::kGroupsSmall;
-constexpr size_t CRC32AcceleratedX86ARMCombinedMultipleStreamsBase::kMaxStreams;
-#endif  // ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-
 template <size_t num_crc_streams, size_t num_pclmul_streams,
           CutoffStrategy strategy>
 class CRC32AcceleratedX86ARMCombinedMultipleStreams
diff --git a/absl/hash/internal/hash.cc b/absl/hash/internal/hash.cc
index e0a8ea99..05705f91 100644
--- a/absl/hash/internal/hash.cc
+++ b/absl/hash/internal/hash.cc
@@ -55,10 +55,6 @@ uint64_t MixingHashState::CombineLargeContiguousImpl64(
 
 ABSL_CONST_INIT const void* const MixingHashState::kSeed = &kSeed;
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr uint64_t MixingHashState::kStaticRandomData[];
-#endif
-
 uint64_t MixingHashState::LowLevelHashImpl(const unsigned char* data,
                                            size_t len) {
   return LowLevelHashLenGt16(data, len, Seed(), &kStaticRandomData[0]);
diff --git a/absl/log/BUILD.bazel b/absl/log/BUILD.bazel
index dc9b0b43..2a9a66d7 100644
--- a/absl/log/BUILD.bazel
+++ b/absl/log/BUILD.bazel
@@ -152,7 +152,6 @@ cc_library(
 
 cc_library(
     name = "log_entry",
-    srcs = ["log_entry.cc"],
     hdrs = ["log_entry.h"],
     copts = ABSL_DEFAULT_COPTS,
     linkopts = ABSL_DEFAULT_LINKOPTS,
diff --git a/absl/log/CMakeLists.txt b/absl/log/CMakeLists.txt
index 73deb45b..a511f03c 100644
--- a/absl/log/CMakeLists.txt
+++ b/absl/log/CMakeLists.txt
@@ -557,8 +557,6 @@ absl_cc_library(
 absl_cc_library(
   NAME
     log_entry
-  SRCS
-    "log_entry.cc"
   HDRS
     "log_entry.h"
   COPTS
diff --git a/absl/log/log_entry.cc b/absl/log/log_entry.cc
deleted file mode 100644
index fe58a576..00000000
--- a/absl/log/log_entry.cc
+++ /dev/null
@@ -1,41 +0,0 @@
-//
-// Copyright 2022 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/log/log_entry.h"
-
-#include "absl/base/config.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr int LogEntry::kNoVerbosityLevel;
-constexpr int LogEntry::kNoVerboseLevel;
-#endif
-
-// https://github.com/abseil/abseil-cpp/issues/1465
-// CMake builds on Apple platforms error when libraries are empty.
-// Our CMake configuration can avoid this error on header-only libraries,
-// but since this library is conditionally empty, including a single
-// variable is an easy workaround.
-#ifdef __APPLE__
-namespace log_internal {
-extern const char kAvoidEmptyLogEntryLibraryWarning;
-const char kAvoidEmptyLogEntryLibraryWarning = 0;
-}  // namespace log_internal
-#endif  // __APPLE__
-
-ABSL_NAMESPACE_END
-}  // namespace absl
diff --git a/absl/numeric/int128.cc b/absl/numeric/int128.cc
index 5d6c68d1..281bf127 100644
--- a/absl/numeric/int128.cc
+++ b/absl/numeric/int128.cc
@@ -342,55 +342,3 @@ std::ostream& operator<<(std::ostream& os, int128 v) {
 
 ABSL_NAMESPACE_END
 }  // namespace absl
-
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-namespace std {
-constexpr bool numeric_limits<absl::uint128>::is_specialized;
-constexpr bool numeric_limits<absl::uint128>::is_signed;
-constexpr bool numeric_limits<absl::uint128>::is_integer;
-constexpr bool numeric_limits<absl::uint128>::is_exact;
-constexpr bool numeric_limits<absl::uint128>::has_infinity;
-constexpr bool numeric_limits<absl::uint128>::has_quiet_NaN;
-constexpr bool numeric_limits<absl::uint128>::has_signaling_NaN;
-constexpr float_denorm_style numeric_limits<absl::uint128>::has_denorm;
-constexpr bool numeric_limits<absl::uint128>::has_denorm_loss;
-constexpr float_round_style numeric_limits<absl::uint128>::round_style;
-constexpr bool numeric_limits<absl::uint128>::is_iec559;
-constexpr bool numeric_limits<absl::uint128>::is_bounded;
-constexpr bool numeric_limits<absl::uint128>::is_modulo;
-constexpr int numeric_limits<absl::uint128>::digits;
-constexpr int numeric_limits<absl::uint128>::digits10;
-constexpr int numeric_limits<absl::uint128>::max_digits10;
-constexpr int numeric_limits<absl::uint128>::radix;
-constexpr int numeric_limits<absl::uint128>::min_exponent;
-constexpr int numeric_limits<absl::uint128>::min_exponent10;
-constexpr int numeric_limits<absl::uint128>::max_exponent;
-constexpr int numeric_limits<absl::uint128>::max_exponent10;
-constexpr bool numeric_limits<absl::uint128>::traps;
-constexpr bool numeric_limits<absl::uint128>::tinyness_before;
-
-constexpr bool numeric_limits<absl::int128>::is_specialized;
-constexpr bool numeric_limits<absl::int128>::is_signed;
-constexpr bool numeric_limits<absl::int128>::is_integer;
-constexpr bool numeric_limits<absl::int128>::is_exact;
-constexpr bool numeric_limits<absl::int128>::has_infinity;
-constexpr bool numeric_limits<absl::int128>::has_quiet_NaN;
-constexpr bool numeric_limits<absl::int128>::has_signaling_NaN;
-constexpr float_denorm_style numeric_limits<absl::int128>::has_denorm;
-constexpr bool numeric_limits<absl::int128>::has_denorm_loss;
-constexpr float_round_style numeric_limits<absl::int128>::round_style;
-constexpr bool numeric_limits<absl::int128>::is_iec559;
-constexpr bool numeric_limits<absl::int128>::is_bounded;
-constexpr bool numeric_limits<absl::int128>::is_modulo;
-constexpr int numeric_limits<absl::int128>::digits;
-constexpr int numeric_limits<absl::int128>::digits10;
-constexpr int numeric_limits<absl::int128>::max_digits10;
-constexpr int numeric_limits<absl::int128>::radix;
-constexpr int numeric_limits<absl::int128>::min_exponent;
-constexpr int numeric_limits<absl::int128>::min_exponent10;
-constexpr int numeric_limits<absl::int128>::max_exponent;
-constexpr int numeric_limits<absl::int128>::max_exponent10;
-constexpr bool numeric_limits<absl::int128>::traps;
-constexpr bool numeric_limits<absl::int128>::tinyness_before;
-}  // namespace std
-#endif
diff --git a/absl/status/status.cc b/absl/status/status.cc
index 745ab889..72a25260 100644
--- a/absl/status/status.cc
+++ b/absl/status/status.cc
@@ -96,10 +96,6 @@ absl::Nonnull<const std::string*> Status::EmptyString() {
   return kEmpty.get();
 }
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr const char Status::kMovedFromString[];
-#endif
-
 absl::Nonnull<const std::string*> Status::MovedFromString() {
   static const absl::NoDestructor<std::string> kMovedFrom(kMovedFromString);
   return kMovedFrom.get();
diff --git a/absl/strings/BUILD.bazel b/absl/strings/BUILD.bazel
index fe43c16b..b81d6f69 100644
--- a/absl/strings/BUILD.bazel
+++ b/absl/strings/BUILD.bazel
@@ -568,7 +568,6 @@ cc_library(
         "cord.cc",
         "cord_analysis.cc",
         "cord_analysis.h",
-        "cord_buffer.cc",
     ],
     hdrs = [
         "cord.h",
diff --git a/absl/strings/CMakeLists.txt b/absl/strings/CMakeLists.txt
index e7ff22ef..40c57f6d 100644
--- a/absl/strings/CMakeLists.txt
+++ b/absl/strings/CMakeLists.txt
@@ -976,7 +976,6 @@ absl_cc_library(
     "cord.cc"
     "cord_analysis.cc"
     "cord_analysis.h"
-    "cord_buffer.cc"
   COPTS
     ${ABSL_DEFAULT_COPTS}
   DEPS
diff --git a/absl/strings/cord.cc b/absl/strings/cord.cc
index f0f4f31a..7f96450a 100644
--- a/absl/strings/cord.cc
+++ b/absl/strings/cord.cc
@@ -163,10 +163,6 @@ static absl::Nonnull<CordRep*> CordRepFromString(std::string&& src) {
 // --------------------------------------------------------------------
 // Cord::InlineRep functions
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr unsigned char Cord::InlineRep::kMaxInline;
-#endif
-
 inline void Cord::InlineRep::set_data(absl::Nonnull<const char*> data,
                                       size_t n) {
   static_assert(kMaxInline == 15, "set_data is hard-coded for a length of 15");
diff --git a/absl/strings/cord_buffer.cc b/absl/strings/cord_buffer.cc
deleted file mode 100644
index fad6269c..00000000
--- a/absl/strings/cord_buffer.cc
+++ /dev/null
@@ -1,30 +0,0 @@
-// Copyright 2022 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/strings/cord_buffer.h"
-
-#include <cstddef>
-
-#include "absl/base/config.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr size_t CordBuffer::kDefaultLimit;
-constexpr size_t CordBuffer::kCustomLimit;
-#endif
-
-ABSL_NAMESPACE_END
-}  // namespace absl
diff --git a/absl/strings/internal/cord_rep_btree.cc b/absl/strings/internal/cord_rep_btree.cc
index 05bd0e20..33ea820d 100644
--- a/absl/strings/internal/cord_rep_btree.cc
+++ b/absl/strings/internal/cord_rep_btree.cc
@@ -36,10 +36,6 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 namespace cord_internal {
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr size_t CordRepBtree::kMaxCapacity;
-#endif
-
 namespace {
 
 using NodeStack = CordRepBtree * [CordRepBtree::kMaxDepth];
diff --git a/absl/strings/internal/cordz_info.cc b/absl/strings/internal/cordz_info.cc
index b7c7fed9..4baaecdc 100644
--- a/absl/strings/internal/cordz_info.cc
+++ b/absl/strings/internal/cordz_info.cc
@@ -34,10 +34,6 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 namespace cord_internal {
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr size_t CordzInfo::kMaxStackDepth;
-#endif
-
 ABSL_CONST_INIT CordzInfo::List CordzInfo::global_list_{absl::kConstInit};
 
 namespace {
diff --git a/absl/strings/internal/str_format/extension.cc b/absl/strings/internal/str_format/extension.cc
index 2a0ceb13..2d441c21 100644
--- a/absl/strings/internal/str_format/extension.cc
+++ b/absl/strings/internal/str_format/extension.cc
@@ -33,28 +33,6 @@ std::string FlagsToString(Flags v) {
   return s;
 }
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-
-#define ABSL_INTERNAL_X_VAL(id) \
-  constexpr absl::FormatConversionChar FormatConversionCharInternal::id;
-ABSL_INTERNAL_CONVERSION_CHARS_EXPAND_(ABSL_INTERNAL_X_VAL, )
-#undef ABSL_INTERNAL_X_VAL
-// NOLINTNEXTLINE(readability-redundant-declaration)
-constexpr absl::FormatConversionChar FormatConversionCharInternal::kNone;
-
-#define ABSL_INTERNAL_CHAR_SET_CASE(c) \
-  constexpr FormatConversionCharSet FormatConversionCharSetInternal::c;
-ABSL_INTERNAL_CONVERSION_CHARS_EXPAND_(ABSL_INTERNAL_CHAR_SET_CASE, )
-#undef ABSL_INTERNAL_CHAR_SET_CASE
-
-constexpr FormatConversionCharSet FormatConversionCharSetInternal::kStar;
-constexpr FormatConversionCharSet FormatConversionCharSetInternal::kIntegral;
-constexpr FormatConversionCharSet FormatConversionCharSetInternal::kFloating;
-constexpr FormatConversionCharSet FormatConversionCharSetInternal::kNumeric;
-constexpr FormatConversionCharSet FormatConversionCharSetInternal::kPointer;
-
-#endif  // ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-
 bool FormatSinkImpl::PutPaddedString(string_view value, int width,
                                      int precision, bool left) {
   size_t space_remaining = 0;
diff --git a/absl/strings/internal/string_constant.h b/absl/strings/internal/string_constant.h
index f68b17d7..d52c3308 100644
--- a/absl/strings/internal/string_constant.h
+++ b/absl/strings/internal/string_constant.h
@@ -50,11 +50,6 @@ struct StringConstant {
                 "The input string_view must point to constant data.");
 };
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-template <typename T>
-constexpr absl::string_view StringConstant<T>::value;
-#endif
-
 // Factory function for `StringConstant` instances.
 // It supports callables that have a constexpr default constructor and a
 // constexpr operator().
diff --git a/absl/strings/string_view.cc b/absl/strings/string_view.cc
index 97025c32..dc2951cf 100644
--- a/absl/strings/string_view.cc
+++ b/absl/strings/string_view.cc
@@ -233,11 +233,6 @@ string_view::size_type string_view::find_last_not_of(
   return npos;
 }
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr string_view::size_type string_view::npos;
-constexpr string_view::size_type string_view::kMaxSize;
-#endif
-
 ABSL_NAMESPACE_END
 }  // namespace absl
 
diff --git a/absl/synchronization/internal/futex_waiter.cc b/absl/synchronization/internal/futex_waiter.cc
index 87eb3b23..8945c176 100644
--- a/absl/synchronization/internal/futex_waiter.cc
+++ b/absl/synchronization/internal/futex_waiter.cc
@@ -31,10 +31,6 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr char FutexWaiter::kName[];
-#endif
-
 int FutexWaiter::WaitUntil(std::atomic<int32_t>* v, int32_t val,
                            KernelTimeout t) {
 #ifdef CLOCK_MONOTONIC
diff --git a/absl/synchronization/internal/kernel_timeout.cc b/absl/synchronization/internal/kernel_timeout.cc
index 48ea6287..252397ab 100644
--- a/absl/synchronization/internal/kernel_timeout.cc
+++ b/absl/synchronization/internal/kernel_timeout.cc
@@ -35,11 +35,6 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr uint64_t KernelTimeout::kNoTimeout;
-constexpr int64_t KernelTimeout::kMaxNanos;
-#endif
-
 int64_t KernelTimeout::SteadyClockNow() {
   if (!SupportsSteadyClock()) {
     return absl::GetCurrentTimeNanos();
diff --git a/absl/synchronization/internal/pthread_waiter.cc b/absl/synchronization/internal/pthread_waiter.cc
index bf700e95..eead9de0 100644
--- a/absl/synchronization/internal/pthread_waiter.cc
+++ b/absl/synchronization/internal/pthread_waiter.cc
@@ -58,10 +58,6 @@ class PthreadMutexHolder {
 };
 }  // namespace
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr char PthreadWaiter::kName[];
-#endif
-
 PthreadWaiter::PthreadWaiter() : waiter_count_(0), wakeup_count_(0) {
   const int err = pthread_mutex_init(&mu_, 0);
   if (err != 0) {
diff --git a/absl/synchronization/internal/sem_waiter.cc b/absl/synchronization/internal/sem_waiter.cc
index d62dbdc7..2119290d 100644
--- a/absl/synchronization/internal/sem_waiter.cc
+++ b/absl/synchronization/internal/sem_waiter.cc
@@ -33,10 +33,6 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr char SemWaiter::kName[];
-#endif
-
 SemWaiter::SemWaiter() : wakeups_(0) {
   if (sem_init(&sem_, 0, 0) != 0) {
     ABSL_RAW_LOG(FATAL, "sem_init failed with errno %d\n", errno);
diff --git a/absl/synchronization/internal/stdcpp_waiter.cc b/absl/synchronization/internal/stdcpp_waiter.cc
index 355718a7..607d683f 100644
--- a/absl/synchronization/internal/stdcpp_waiter.cc
+++ b/absl/synchronization/internal/stdcpp_waiter.cc
@@ -30,10 +30,6 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr char StdcppWaiter::kName[];
-#endif
-
 StdcppWaiter::StdcppWaiter() : waiter_count_(0), wakeup_count_(0) {}
 
 bool StdcppWaiter::Wait(KernelTimeout t) {
diff --git a/absl/synchronization/internal/waiter_base.cc b/absl/synchronization/internal/waiter_base.cc
index 46928b40..e9797f8b 100644
--- a/absl/synchronization/internal/waiter_base.cc
+++ b/absl/synchronization/internal/waiter_base.cc
@@ -21,10 +21,6 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr int WaiterBase::kIdlePeriods;
-#endif
-
 void WaiterBase::MaybeBecomeIdle() {
   base_internal::ThreadIdentity *identity =
       base_internal::CurrentThreadIdentityIfPresent();
diff --git a/absl/synchronization/internal/win32_waiter.cc b/absl/synchronization/internal/win32_waiter.cc
index bd95ff08..b2fe402c 100644
--- a/absl/synchronization/internal/win32_waiter.cc
+++ b/absl/synchronization/internal/win32_waiter.cc
@@ -28,10 +28,6 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
-#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr char Win32Waiter::kName[];
-#endif
-
 class Win32Waiter::WinHelper {
  public:
   static SRWLOCK *GetLock(Win32Waiter *w) {