Export of internal Abseil changes.

--
ab1a58c85a462884413ec0022dc1fff19ccb8602 by Abseil Team <absl-team@google.com>:

Clarified the documentation in str_format.h to say that use of absl::FormatSpec
is ok for wrapper functions. Added tests that express this.

PiperOrigin-RevId: 247657991

--
fef9481e58d579f1514babcb960ca60a51883fd8 by CJ Johnson <johnsoncj@google.com>:

Adds exception safety tests for InlinedVector::InlinedVector() and InlinedVector::InlinedVector(const allocator_type&).

PiperOrigin-RevId: 247617048

--
ef3217e1cd1e9a6ff5f2025e061b8ce3735af78f by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 247614063

--
ed4c3345c4a04d8ec5c9e627058f17fce55925b1 by CJ Johnson <johnsoncj@google.com>:

Update InlinedVector::clear()

Introduces inlined_vector_exception_safety_test with the first test (clear), adds new benchmarks (for clear), and updates the implementation of clear.

PiperOrigin-RevId: 247496049

--
144a3a77c93bc8b2226da6f4b56166ee3d9868de by Derek Mauro <dmauro@google.com>:

Internal change

PiperOrigin-RevId: 247482532

--
286bbb89e154d5424955b644edad5fe04be487f8 by Derek Mauro <dmauro@google.com>:

Add scripts to run ASAN and TSAN on CI.

PiperOrigin-RevId: 247479658
GitOrigin-RevId: ab1a58c85a462884413ec0022dc1fff19ccb8602
Change-Id: Ief4c5a62587d0c59d405735df469d498aa6bf101

16 files changed, 258 insertions, 36 deletions

diff --git a/absl/base/BUILD.bazel b/absl/base/BUILD.bazel
index 9fb1d8cd..317452da 100644
--- a/absl/base/BUILD.bazel
+++ b/absl/base/BUILD.bazel
@@ -444,7 +444,7 @@ cc_test(
 
 cc_test(
     name = "low_level_alloc_test",
-    size = "small",
+    size = "medium",
     srcs = ["internal/low_level_alloc_test.cc"],
     copts = ABSL_TEST_COPTS,
     linkopts = ABSL_DEFAULT_LINKOPTS,
diff --git a/absl/container/BUILD.bazel b/absl/container/BUILD.bazel
index 0488857e..99a72482 100644
--- a/absl/container/BUILD.bazel
+++ b/absl/container/BUILD.bazel
@@ -198,11 +198,23 @@ cc_test(
     deps = [
         ":inlined_vector",
         "//absl/base",
+        "//absl/base:core_headers",
         "//absl/strings",
         "@com_github_google_benchmark//:benchmark_main",
     ],
 )
 
+cc_test(
+    name = "inlined_vector_exception_safety_test",
+    srcs = ["inlined_vector_exception_safety_test.cc"],
+    copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    deps = [
+        ":inlined_vector",
+        "//absl/base:exception_safety_testing",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
 cc_library(
     name = "test_instance_tracker",
     testonly = 1,
diff --git a/absl/container/CMakeLists.txt b/absl/container/CMakeLists.txt
index 1e203dbf..526e37af 100644
--- a/absl/container/CMakeLists.txt
+++ b/absl/container/CMakeLists.txt
@@ -195,6 +195,22 @@ absl_cc_test(
     gmock_main
 )
 
+absl_cc_test(
+  NAME
+    inlined_vector_exception_safety_test
+  SRCS
+    "inlined_vector_exception_safety_test.cc"
+  COPTS
+    ${ABSL_TEST_COPTS}
+    ${ABSL_EXCEPTIONS_FLAG}
+  LINKOPTS
+    ${ABSL_EXCEPTIONS_FLAG_LINKOPTS}
+  DEPS
+    absl::inlined_vector
+    absl::exception_safety_testing
+    gmock_main
+)
+
 absl_cc_library(
   NAME
     test_instance_tracker
diff --git a/absl/container/inlined_vector.h b/absl/container/inlined_vector.h
index 16865272..61e0cfb4 100644
--- a/absl/container/inlined_vector.h
+++ b/absl/container/inlined_vector.h
@@ -784,16 +784,20 @@ class InlinedVector {
   // Destroys all elements in the inlined vector, sets the size of `0` and
   // deallocates the heap allocation if the inlined vector was allocated.
   void clear() noexcept {
-    size_type s = size();
-    if (storage_.GetIsAllocated()) {
-      Destroy(storage_.GetAllocatedData(), storage_.GetAllocatedData() + s);
-      AllocatorTraits::deallocate(storage_.GetAllocator(),
-                                  storage_.GetAllocatedData(),
+    const bool is_allocated = storage_.GetIsAllocated();
+
+    pointer the_data =
+        is_allocated ? storage_.GetAllocatedData() : storage_.GetInlinedData();
+
+    inlined_vector_internal::DestroyElements(storage_.GetAllocator(), the_data,
+                                             storage_.GetSize());
+
+    if (is_allocated) {
+      AllocatorTraits::deallocate(storage_.GetAllocator(), the_data,
                                   storage_.GetAllocatedCapacity());
-    } else if (s != 0) {  // do nothing for empty vectors
-      Destroy(storage_.GetInlinedData(), storage_.GetInlinedData() + s);
     }
-    storage_.SetInlinedSize(0);
+
+    storage_.SetInlinedSize(/* size = */ 0);
   }
 
   // `InlinedVector::reserve()`
diff --git a/absl/container/inlined_vector_benchmark.cc b/absl/container/inlined_vector_benchmark.cc
index 867a29ea..7bb3271b 100644
--- a/absl/container/inlined_vector_benchmark.cc
+++ b/absl/container/inlined_vector_benchmark.cc
@@ -1,4 +1,4 @@
-// Copyright 2017 The Abseil Authors.
+// 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.
@@ -12,13 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#include "absl/container/inlined_vector.h"
-
 #include <string>
 #include <vector>
 
 #include "benchmark/benchmark.h"
 #include "absl/base/internal/raw_logging.h"
+#include "absl/base/macros.h"
+#include "absl/container/inlined_vector.h"
 #include "absl/strings/str_cat.h"
 
 namespace {
@@ -373,4 +373,72 @@ void BM_StdVectorEmpty(benchmark::State& state) {
 }
 BENCHMARK(BM_StdVectorEmpty);
 
+constexpr size_t kInlineElements = 4;
+constexpr size_t kSmallSize = kInlineElements / 2;
+constexpr size_t kLargeSize = kInlineElements * 2;
+constexpr size_t kBatchSize = 100;
+
+struct TrivialType {
+  size_t val;
+};
+
+using TrivialVec = absl::InlinedVector<TrivialType, kInlineElements>;
+
+class NontrivialType {
+ public:
+  ABSL_ATTRIBUTE_NOINLINE NontrivialType() : val_() {}
+
+  ABSL_ATTRIBUTE_NOINLINE NontrivialType(const NontrivialType& other)
+      : val_(other.val_) {}
+
+  ABSL_ATTRIBUTE_NOINLINE NontrivialType& operator=(
+      const NontrivialType& other) {
+    val_ = other.val_;
+    return *this;
+  }
+
+  ABSL_ATTRIBUTE_NOINLINE ~NontrivialType() noexcept {}
+
+ private:
+  size_t val_;
+};
+
+using NontrivialVec = absl::InlinedVector<NontrivialType, kInlineElements>;
+
+#define BENCHMARK_OPERATION(BM_Function)                      \
+  BENCHMARK_TEMPLATE(BM_Function, TrivialVec, kSmallSize);    \
+  BENCHMARK_TEMPLATE(BM_Function, TrivialVec, kLargeSize);    \
+  BENCHMARK_TEMPLATE(BM_Function, NontrivialVec, kSmallSize); \
+  BENCHMARK_TEMPLATE(BM_Function, NontrivialVec, kLargeSize)
+
+template <typename VecT, typename PrepareVec, typename TestVec>
+void BatchedBenchmark(benchmark::State& state, PrepareVec prepare_vec,
+                      TestVec test_vec) {
+  VecT vectors[kBatchSize];
+
+  while (state.KeepRunningBatch(kBatchSize)) {
+    // Prepare batch
+    state.PauseTiming();
+    for (auto& vec : vectors) {
+      prepare_vec(&vec);
+    }
+    benchmark::DoNotOptimize(vectors);
+    state.ResumeTiming();
+
+    // Test batch
+    for (auto& vec : vectors) {
+      test_vec(&vec);
+    }
+  }
+}
+
+template <typename VecT, size_t Size>
+void BM_Clear(benchmark::State& state) {
+  BatchedBenchmark<VecT>(
+      state,
+      /* prepare_vec = */ [](VecT* vec) { vec->resize(Size); },
+      /* test_vec = */ [](VecT* vec) { vec->clear(); });
+}
+BENCHMARK_OPERATION(BM_Clear);
+
 }  // namespace
diff --git a/absl/container/inlined_vector_exception_safety_test.cc b/absl/container/inlined_vector_exception_safety_test.cc
new file mode 100644
index 00000000..0af048b1
--- /dev/null
+++ b/absl/container/inlined_vector_exception_safety_test.cc
@@ -0,0 +1,55 @@
+// Copyright 2019 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <memory>
+
+#include "gtest/gtest.h"
+#include "absl/base/internal/exception_safety_testing.h"
+#include "absl/container/inlined_vector.h"
+
+namespace {
+
+constexpr size_t kInlined = 4;
+constexpr size_t kSmallSize = kInlined / 2;
+constexpr size_t kLargeSize = kInlined * 2;
+
+using Thrower = testing::ThrowingValue<>;
+using ThrowerAlloc = testing::ThrowingAllocator<Thrower>;
+
+template <typename Allocator = std::allocator<Thrower>>
+using InlVec = absl::InlinedVector<Thrower, kInlined, Allocator>;
+
+TEST(InlinedVector, DefaultConstructor) {
+  testing::TestThrowingCtor<InlVec<>>();
+
+  testing::TestThrowingCtor<InlVec<ThrowerAlloc>>();
+}
+
+TEST(InlinedVector, AllocConstructor) {
+  auto alloc = std::allocator<Thrower>();
+  testing::TestThrowingCtor<InlVec<>>(alloc);
+
+  auto throw_alloc = ThrowerAlloc();
+  testing::TestThrowingCtor<InlVec<ThrowerAlloc>>(throw_alloc);
+}
+
+TEST(InlinedVector, Clear) {
+  auto small_vec = InlVec<>(kSmallSize);
+  EXPECT_TRUE(testing::TestNothrowOp([&]() { small_vec.clear(); }));
+
+  auto large_vec = InlVec<>(kLargeSize);
+  EXPECT_TRUE(testing::TestNothrowOp([&]() { large_vec.clear(); }));
+}
+
+}  // namespace
diff --git a/absl/container/internal/inlined_vector.h b/absl/container/internal/inlined_vector.h
index 6a5a75be..4589ce08 100644
--- a/absl/container/internal/inlined_vector.h
+++ b/absl/container/internal/inlined_vector.h
@@ -16,6 +16,7 @@
 #define ABSL_CONTAINER_INTERNAL_INLINED_VECTOR_INTERNAL_H_
 
 #include <cstddef>
+#include <cstring>
 #include <iterator>
 #include <memory>
 #include <utility>
@@ -31,6 +32,33 @@ using IsAtLeastForwardIterator = std::is_convertible<
     typename std::iterator_traits<Iterator>::iterator_category,
     std::forward_iterator_tag>;
 
+template <typename AllocatorType, typename ValueType, typename SizeType>
+void DestroyElements(AllocatorType alloc, ValueType* destroy_first,
+                     SizeType destroy_size) {
+  using AllocatorTraits = std::allocator_traits<AllocatorType>;
+
+  // Destroys `destroy_size` elements from `destroy_first`.
+  //
+  // Destroys the range
+  //   [`destroy_first`, `destroy_first + destroy_size`).
+  //
+  // NOTE: We assume destructors do not throw and thus make no attempt to roll
+  // back.
+  for (SizeType i = 0; i < destroy_size; ++i) {
+    AllocatorTraits::destroy(alloc, destroy_first + i);
+  }
+
+#ifndef NDEBUG
+  // Overwrite unused memory with `0xab` so we can catch uninitialized usage.
+  //
+  // Cast to `void*` to tell the compiler that we don't care that we might be
+  // scribbling on a vtable pointer.
+  void* memory = reinterpret_cast<void*>(destroy_first);
+  size_t memory_size = sizeof(ValueType) * destroy_size;
+  std::memset(memory, 0xab, memory_size);
+#endif  // NDEBUG
+}
+
 template <typename T, size_t N, typename A>
 class Storage {
  public:
diff --git a/absl/debugging/BUILD.bazel b/absl/debugging/BUILD.bazel
index 0854314e..e4aed5e4 100644
--- a/absl/debugging/BUILD.bazel
+++ b/absl/debugging/BUILD.bazel
@@ -244,6 +244,7 @@ cc_test(
         "//conditions:default": [],
     }),
     linkopts = ABSL_LSAN_LINKOPTS + ABSL_DEFAULT_LINKOPTS,
+    tags = ["notsan"],
     deps = [
         ":leak_check_api_enabled_for_testing",
         "//absl/base",
@@ -256,6 +257,7 @@ cc_test(
     srcs = ["leak_check_test.cc"],
     copts = ["-UABSL_EXPECT_LEAK_SANITIZER"],
     linkopts = ABSL_DEFAULT_LINKOPTS,
+    tags = ["noasan"],
     deps = [
         ":leak_check_api_disabled_for_testing",
         "//absl/base",  # for raw_logging
@@ -271,6 +273,7 @@ cc_test(
     name = "disabled_leak_check_test",
     srcs = ["leak_check_fail_test.cc"],
     linkopts = ABSL_LSAN_LINKOPTS + ABSL_DEFAULT_LINKOPTS,
+    tags = ["notsan"],
     deps = [
         ":leak_check_api_enabled_for_testing",
         ":leak_check_disable",
diff --git a/absl/hash/BUILD.bazel b/absl/hash/BUILD.bazel
index e1e6eae8..8c2daf70 100644
--- a/absl/hash/BUILD.bazel
+++ b/absl/hash/BUILD.bazel
@@ -35,10 +35,10 @@ cc_library(
     copts = ABSL_DEFAULT_COPTS,
     linkopts = ABSL_DEFAULT_LINKOPTS,
     deps = [
+        ":city",
         "//absl/base:core_headers",
         "//absl/base:endian",
         "//absl/container:fixed_array",
-        "//absl/hash:city",
         "//absl/meta:type_traits",
         "//absl/numeric:int128",
         "//absl/strings",
diff --git a/absl/strings/BUILD.bazel b/absl/strings/BUILD.bazel
index 2b194737..d6ce88da 100644
--- a/absl/strings/BUILD.bazel
+++ b/absl/strings/BUILD.bazel
@@ -404,7 +404,7 @@ cc_test(
 
 cc_test(
     name = "numbers_test",
-    size = "small",
+    size = "medium",
     srcs = [
         "internal/numbers_test_common.h",
         "numbers_test.cc",
@@ -628,7 +628,7 @@ cc_test(
 
 cc_test(
     name = "str_format_convert_test",
-    size = "small",
+    size = "medium",
     srcs = ["internal/str_format/convert_test.cc"],
     copts = ABSL_TEST_COPTS,
     visibility = ["//visibility:private"],
diff --git a/absl/strings/str_format.h b/absl/strings/str_format.h
index 539d9516..da3208e1 100644
--- a/absl/strings/str_format.h
+++ b/absl/strings/str_format.h
@@ -50,7 +50,7 @@
 //   * A `ParsedFormat` instance, which encapsulates a specific, pre-compiled
 //     format string for a specific set of type(s), and which can be passed
 //     between API boundaries. (The `FormatSpec` type should not be used
-//     directly.)
+//     directly except as an argument type for wrapper functions.)
 //
 // The `str_format` library provides the ability to output its format strings to
 // arbitrary sink types:
@@ -157,10 +157,15 @@ class FormatCountCapture {
 // FormatSpec
 //
 // The `FormatSpec` type defines the makeup of a format string within the
-// `str_format` library. You should not need to use or manipulate this type
-// directly. A `FormatSpec` is a variadic class template that is evaluated at
-// compile-time, according to the format string and arguments that are passed
-// to it.
+// `str_format` library. It is a variadic class template that is evaluated at
+// compile-time, according to the format string and arguments that are passed to
+// it.
+//
+// You should not need to manipulate this type directly. You should only name it
+// if you are writing wrapper functions which accept format arguments that will
+// be provided unmodified to functions in this library. Such a wrapper function
+// might be a class method that provides format arguments and/or internally uses
+// the result of formatting.
 //
 // For a `FormatSpec` to be valid at compile-time, it must be provided as
 // either:
diff --git a/absl/strings/str_format_test.cc b/absl/strings/str_format_test.cc
index d4cffa08..80830b36 100644
--- a/absl/strings/str_format_test.cc
+++ b/absl/strings/str_format_test.cc
@@ -13,7 +13,7 @@ namespace absl {
 namespace {
 using str_format_internal::FormatArgImpl;
 
-class FormatEntryPointTest : public ::testing::Test { };
+using FormatEntryPointTest = ::testing::Test;
 
 TEST_F(FormatEntryPointTest, Format) {
   std::string sink;
@@ -458,7 +458,7 @@ std::string SummarizeParsedFormat(const ParsedFormatBase& pc) {
   return out;
 }
 
-class ParsedFormatTest : public testing::Test {};
+using ParsedFormatTest = ::testing::Test;
 
 TEST_F(ParsedFormatTest, SimpleChecked) {
   EXPECT_EQ("[ABC]{d:1$d}[DEF]",
@@ -600,6 +600,24 @@ TEST_F(ParsedFormatTest, RegressionMixPositional) {
   EXPECT_FALSE((ExtendedParsedFormat<Conv::d, Conv::o>::New("%1$d %o")));
 }
 
+using FormatWrapperTest = ::testing::Test;
+
+// Plain wrapper for StrFormat.
+template <typename... Args>
+std::string WrappedFormat(const absl::FormatSpec<Args...>& format,
+                          const Args&... args) {
+  return StrFormat(format, args...);
+}
+
+TEST_F(FormatWrapperTest, ConstexprStringFormat) {
+  EXPECT_EQ(WrappedFormat("%s there", "hello"), "hello there");
+}
+
+TEST_F(FormatWrapperTest, ParsedFormat) {
+  ParsedFormat<'s'> format("%s there");
+  EXPECT_EQ(WrappedFormat(format, "hello"), "hello there");
+}
+
 }  // namespace
 }  // namespace absl
 
diff --git a/absl/synchronization/mutex.cc b/absl/synchronization/mutex.cc
index 37ffff3d..3e8033a0 100644
--- a/absl/synchronization/mutex.cc
+++ b/absl/synchronization/mutex.cc
@@ -154,7 +154,7 @@ static int Delay(int32_t c, DelayMode mode) {
   if (c < limit) {
     c++;               // spin
   } else {
-    ABSL_TSAN_MUTEX_PRE_DIVERT(0, 0);
+    ABSL_TSAN_MUTEX_PRE_DIVERT(nullptr, 0);
     if (c == limit) {  // yield once
       AbslInternalMutexYield();
       c++;
@@ -162,7 +162,7 @@ static int Delay(int32_t c, DelayMode mode) {
       absl::SleepFor(absl::Microseconds(10));
       c = 0;
     }
-    ABSL_TSAN_MUTEX_POST_DIVERT(0, 0);
+    ABSL_TSAN_MUTEX_POST_DIVERT(nullptr, 0);
   }
   return (c);
 }
@@ -2583,7 +2583,7 @@ void CondVar::Wakeup(PerThreadSynch *w) {
 }
 
 void CondVar::Signal() {
-  ABSL_TSAN_MUTEX_PRE_SIGNAL(0, 0);
+  ABSL_TSAN_MUTEX_PRE_SIGNAL(nullptr, 0);
   intptr_t v;
   int c = 0;
   for (v = cv_.load(std::memory_order_relaxed); v != 0;
@@ -2612,17 +2612,17 @@ void CondVar::Signal() {
       if ((v & kCvEvent) != 0) {
         PostSynchEvent(this, SYNCH_EV_SIGNAL);
       }
-      ABSL_TSAN_MUTEX_POST_SIGNAL(0, 0);
+      ABSL_TSAN_MUTEX_POST_SIGNAL(nullptr, 0);
       return;
     } else {
       c = Delay(c, GENTLE);
     }
   }
-  ABSL_TSAN_MUTEX_POST_SIGNAL(0, 0);
+  ABSL_TSAN_MUTEX_POST_SIGNAL(nullptr, 0);
 }
 
 void CondVar::SignalAll () {
-  ABSL_TSAN_MUTEX_PRE_SIGNAL(0, 0);
+  ABSL_TSAN_MUTEX_PRE_SIGNAL(nullptr, 0);
   intptr_t v;
   int c = 0;
   for (v = cv_.load(std::memory_order_relaxed); v != 0;
@@ -2649,13 +2649,13 @@ void CondVar::SignalAll () {
       if ((v & kCvEvent) != 0) {
         PostSynchEvent(this, SYNCH_EV_SIGNALALL);
       }
-      ABSL_TSAN_MUTEX_POST_SIGNAL(0, 0);
+      ABSL_TSAN_MUTEX_POST_SIGNAL(nullptr, 0);
       return;
     } else {
       c = Delay(c, GENTLE);           // try again after a delay
     }
   }
-  ABSL_TSAN_MUTEX_POST_SIGNAL(0, 0);
+  ABSL_TSAN_MUTEX_POST_SIGNAL(nullptr, 0);
 }
 
 void ReleasableMutexLock::Release() {
diff --git a/absl/synchronization/mutex_test.cc b/absl/synchronization/mutex_test.cc
index 10211229..2e10f098 100644
--- a/absl/synchronization/mutex_test.cc
+++ b/absl/synchronization/mutex_test.cc
@@ -815,7 +815,12 @@ TEST(Mutex, MutexReaderDecrementBug) NO_THREAD_SAFETY_ANALYSIS {
 
 // Test that we correctly handle the situation when a lock is
 // held and then destroyed (w/o unlocking).
+#ifdef THREAD_SANITIZER
+// TSAN reports errors when locked Mutexes are destroyed.
+TEST(Mutex, DISABLED_LockedMutexDestructionBug) NO_THREAD_SAFETY_ANALYSIS {
+#else
 TEST(Mutex, LockedMutexDestructionBug) NO_THREAD_SAFETY_ANALYSIS {
+#endif
   for (int i = 0; i != 10; i++) {
     // Create, lock and destroy 10 locks.
     const int kNumLocks = 10;
@@ -1062,7 +1067,12 @@ class ScopedDisableBazelTestWarnings {
 const char ScopedDisableBazelTestWarnings::kVarName[] =
     "TEST_WARNINGS_OUTPUT_FILE";
 
+#ifdef THREAD_SANITIZER
+// This test intentionally creates deadlocks to test the deadlock detector.
+TEST(Mutex, DISABLED_DeadlockDetectorBazelWarning) {
+#else
 TEST(Mutex, DeadlockDetectorBazelWarning) {
+#endif
   absl::SetMutexDeadlockDetectionMode(absl::OnDeadlockCycle::kReport);
 
   // Cause deadlock detection to detect something, if it's
@@ -1109,7 +1119,12 @@ TEST(Mutex, DeadlockDetectorStessTest) NO_THREAD_SAFETY_ANALYSIS {
   }
 }
 
+#ifdef THREAD_SANITIZER
+// TSAN reports errors when locked Mutexes are destroyed.
+TEST(Mutex, DISABLED_DeadlockIdBug) NO_THREAD_SAFETY_ANALYSIS {
+#else
 TEST(Mutex, DeadlockIdBug) NO_THREAD_SAFETY_ANALYSIS {
+#endif
   // Test a scenario where a cached deadlock graph node id in the
   // list of held locks is not invalidated when the corresponding
   // mutex is deleted.
diff --git a/absl/types/compare.h b/absl/types/compare.h
index 7fed3081..50361d62 100644
--- a/absl/types/compare.h
+++ b/absl/types/compare.h
@@ -452,8 +452,10 @@ namespace compare_internal {
 
 // Helper functions to do a boolean comparison of two keys given a boolean
 // or three-way comparator.
-constexpr bool compare_result_as_less_than(const bool r) { return r; }
-constexpr bool compare_result_as_less_than(const int r) { return r < 0; }
+// SFINAE prevents implicit conversions to bool (such as from int).
+template <typename Bool,
+          absl::enable_if_t<std::is_same<bool, Bool>::value, int> = 0>
+constexpr bool compare_result_as_less_than(const Bool r) { return r; }
 constexpr bool compare_result_as_less_than(const absl::weak_ordering r) {
   return r < 0;
 }
diff --git a/absl/types/compare_test.cc b/absl/types/compare_test.cc
index dd0388c1..3a855421 100644
--- a/absl/types/compare_test.cc
+++ b/absl/types/compare_test.cc
@@ -200,10 +200,6 @@ TEST(CompareResultAsLessThan, SanityTest) {
   EXPECT_FALSE(absl::compare_internal::compare_result_as_less_than(false));
   EXPECT_TRUE(absl::compare_internal::compare_result_as_less_than(true));
 
-  EXPECT_TRUE(absl::compare_internal::compare_result_as_less_than(-1));
-  EXPECT_FALSE(absl::compare_internal::compare_result_as_less_than(0));
-  EXPECT_FALSE(absl::compare_internal::compare_result_as_less_than(1));
-
   EXPECT_TRUE(
       absl::compare_internal::compare_result_as_less_than(weak_ordering::less));
   EXPECT_FALSE(absl::compare_internal::compare_result_as_less_than(