merge(3p/abseil_cpp): Merge upstream at 'ccdbb5941' r/1011

Change-Id: I6e85fc7b5f76bba1f1eef15e600a8acb64e97ef5

15 files changed, 440 insertions, 335 deletions

diff --git a/third_party/abseil_cpp/absl/random/BUILD.bazel b/third_party/abseil_cpp/absl/random/BUILD.bazel
index 9ba75b5236c5..694331c2080d 100644
--- a/third_party/abseil_cpp/absl/random/BUILD.bazel
+++ b/third_party/abseil_cpp/absl/random/BUILD.bazel
@@ -69,7 +69,7 @@ cc_library(
         "//absl/base:config",
         "//absl/base:core_headers",
         "//absl/meta:type_traits",
-        "//absl/random/internal:distributions",
+        "//absl/random/internal:distribution_caller",
         "//absl/random/internal:fast_uniform_bits",
         "//absl/random/internal:fastmath",
         "//absl/random/internal:generate_real",
@@ -78,7 +78,6 @@ cc_library(
         "//absl/random/internal:uniform_helper",
         "//absl/random/internal:wide_multiply",
         "//absl/strings",
-        "//absl/types:span",
     ],
 )
 
@@ -116,11 +115,12 @@ cc_library(
     copts = ABSL_DEFAULT_COPTS,
     linkopts = ABSL_DEFAULT_LINKOPTS,
     deps = [
+        ":random",
         "//absl/base:core_headers",
+        "//absl/base:fast_type_id",
         "//absl/meta:type_traits",
         "//absl/random/internal:distribution_caller",
         "//absl/random/internal:fast_uniform_bits",
-        "//absl/random/internal:mocking_bit_gen_base",
     ],
 )
 
@@ -146,10 +146,11 @@ cc_library(
     linkopts = ABSL_DEFAULT_LINKOPTS,
     deps = [
         ":distributions",
+        ":random",
+        "//absl/base:fast_type_id",
         "//absl/container:flat_hash_map",
         "//absl/meta:type_traits",
         "//absl/random/internal:distribution_caller",
-        "//absl/random/internal:mocking_bit_gen_base",
         "//absl/strings",
         "//absl/types:span",
         "//absl/types:variant",
@@ -411,6 +412,7 @@ cc_test(
     deps = [
         ":bit_gen_ref",
         ":random",
+        "//absl/base:fast_type_id",
         "//absl/random/internal:sequence_urbg",
         "@com_google_googletest//:gtest_main",
     ],
diff --git a/third_party/abseil_cpp/absl/random/CMakeLists.txt b/third_party/abseil_cpp/absl/random/CMakeLists.txt
index ec616dd9526a..ade9ea10f17e 100644
--- a/third_party/abseil_cpp/absl/random/CMakeLists.txt
+++ b/third_party/abseil_cpp/absl/random/CMakeLists.txt
@@ -45,7 +45,6 @@ absl_cc_library(
     absl::core_headers
     absl::random_internal_distribution_caller
     absl::random_internal_fast_uniform_bits
-    absl::random_internal_mocking_bit_gen_base
     absl::type_traits
 )
 
@@ -62,6 +61,7 @@ absl_cc_test(
     absl::random_bit_gen_ref
     absl::random_random
     absl::random_internal_sequence_urbg
+    absl::fast_type_id
     gmock
     gtest_main
 )
@@ -69,16 +69,16 @@ absl_cc_test(
 # Internal-only target, do not depend on directly.
 absl_cc_library(
   NAME
-    random_internal_mocking_bit_gen_base
+    random_internal_mock_helpers
   HDRS
-    "internal/mocking_bit_gen_base.h"
+    "internal/mock_helpers.h"
   COPTS
     ${ABSL_DEFAULT_COPTS}
   LINKOPTS
     ${ABSL_DEFAULT_LINKOPTS}
   DEPS
-    absl::random_random
-    absl::strings
+    absl::fast_type_id
+    absl::optional
 )
 
 # Internal-only target, do not depend on directly.
@@ -93,6 +93,7 @@ absl_cc_library(
     ${ABSL_DEFAULT_LINKOPTS}
   DEPS
     absl::random_mocking_bit_gen
+    absl::random_internal_mock_helpers
   TESTONLY
 )
 
@@ -111,8 +112,8 @@ absl_cc_library(
     absl::raw_logging_internal
     absl::random_distributions
     absl::random_internal_distribution_caller
-    absl::random_internal_mocking_bit_gen_base
     absl::random_internal_mock_overload_set
+    absl::random_random
     absl::strings
     absl::span
     absl::type_traits
@@ -183,7 +184,7 @@ absl_cc_library(
     absl::config
     absl::core_headers
     absl::random_internal_generate_real
-    absl::random_internal_distributions
+    absl::random_internal_distribution_caller
     absl::random_internal_fast_uniform_bits
     absl::random_internal_fastmath
     absl::random_internal_iostream_state_saver
@@ -191,7 +192,6 @@ absl_cc_library(
     absl::random_internal_uniform_helper
     absl::random_internal_wide_multiply
     absl::strings
-    absl::span
     absl::type_traits
 )
 
@@ -534,27 +534,8 @@ absl_cc_library(
     ${ABSL_DEFAULT_LINKOPTS}
   DEPS
     absl::config
-)
-
-# Internal-only target, do not depend on directly.
-absl_cc_library(
-  NAME
-    random_internal_distributions
-  HDRS
-    "internal/distributions.h"
-  COPTS
-    ${ABSL_DEFAULT_COPTS}
-  LINKOPTS
-    ${ABSL_DEFAULT_LINKOPTS}
-  DEPS
-    absl::random_internal_distribution_caller
-    absl::random_internal_fast_uniform_bits
-    absl::random_internal_fastmath
-    absl::random_internal_traits
-    absl::random_internal_uniform_helper
-    absl::span
-    absl::strings
-    absl::type_traits
+    absl::utility
+    absl::fast_type_id
 )
 
 # Internal-only target, do not depend on directly.
@@ -745,7 +726,6 @@ absl_cc_library(
     absl::random_internal_salted_seed_seq
     absl::random_internal_seed_material
     absl::span
-    absl::strings
     absl::type_traits
 )
 
@@ -1174,9 +1154,7 @@ absl_cc_library(
   LINKOPTS
     ${ABSL_DEFAULT_LINKOPTS}
   DEPS
-    absl::core_headers
-    absl::random_internal_fast_uniform_bits
-    absl::random_internal_iostream_state_saver
+    absl::config
     absl::random_internal_traits
     absl::type_traits
 )
diff --git a/third_party/abseil_cpp/absl/random/bit_gen_ref.h b/third_party/abseil_cpp/absl/random/bit_gen_ref.h
index 59591a479d8c..9555460fd491 100644
--- a/third_party/abseil_cpp/absl/random/bit_gen_ref.h
+++ b/third_party/abseil_cpp/absl/random/bit_gen_ref.h
@@ -24,11 +24,11 @@
 #ifndef ABSL_RANDOM_BIT_GEN_REF_H_
 #define ABSL_RANDOM_BIT_GEN_REF_H_
 
+#include "absl/base/internal/fast_type_id.h"
 #include "absl/base/macros.h"
 #include "absl/meta/type_traits.h"
 #include "absl/random/internal/distribution_caller.h"
 #include "absl/random/internal/fast_uniform_bits.h"
-#include "absl/random/internal/mocking_bit_gen_base.h"
 
 namespace absl {
 ABSL_NAMESPACE_BEGIN
@@ -51,6 +51,10 @@ struct is_urbg<
         typename std::decay<decltype(std::declval<URBG>()())>::type>::value>>
     : std::true_type {};
 
+template <typename>
+struct DistributionCaller;
+class MockHelpers;
+
 }  // namespace random_internal
 
 // -----------------------------------------------------------------------------
@@ -77,23 +81,50 @@ struct is_urbg<
 //    }
 //
 class BitGenRef {
- public:
-  using result_type = uint64_t;
+  // SFINAE to detect whether the URBG type includes a member matching
+  // bool InvokeMock(base_internal::FastTypeIdType, void*, void*).
+  //
+  // These live inside BitGenRef so that they have friend access
+  // to MockingBitGen. (see similar methods in DistributionCaller).
+  template <template <class...> class Trait, class AlwaysVoid, class... Args>
+  struct detector : std::false_type {};
+  template <template <class...> class Trait, class... Args>
+  struct detector<Trait, absl::void_t<Trait<Args...>>, Args...>
+      : std::true_type {};
+
+  template <class T>
+  using invoke_mock_t = decltype(std::declval<T*>()->InvokeMock(
+      std::declval<base_internal::FastTypeIdType>(), std::declval<void*>(),
+      std::declval<void*>()));
+
+  template <typename T>
+  using HasInvokeMock = typename detector<invoke_mock_t, void, T>::type;
 
-  BitGenRef(const absl::BitGenRef&) = default;
-  BitGenRef(absl::BitGenRef&&) = default;
-  BitGenRef& operator=(const absl::BitGenRef&) = default;
-  BitGenRef& operator=(absl::BitGenRef&&) = default;
+ public:
+  BitGenRef(const BitGenRef&) = default;
+  BitGenRef(BitGenRef&&) = default;
+  BitGenRef& operator=(const BitGenRef&) = default;
+  BitGenRef& operator=(BitGenRef&&) = default;
+
+  template <typename URBG, typename absl::enable_if_t<
+                               (!std::is_same<URBG, BitGenRef>::value &&
+                                random_internal::is_urbg<URBG>::value &&
+                                !HasInvokeMock<URBG>::value)>* = nullptr>
+  BitGenRef(URBG& gen)  // NOLINT
+      : t_erased_gen_ptr_(reinterpret_cast<uintptr_t>(&gen)),
+        mock_call_(NotAMock),
+        generate_impl_fn_(ImplFn<URBG>) {}
 
   template <typename URBG,
-            typename absl::enable_if_t<
-                (!std::is_same<URBG, BitGenRef>::value &&
-                 random_internal::is_urbg<URBG>::value)>* = nullptr>
+            typename absl::enable_if_t<(!std::is_same<URBG, BitGenRef>::value &&
+                                        random_internal::is_urbg<URBG>::value &&
+                                        HasInvokeMock<URBG>::value)>* = nullptr>
   BitGenRef(URBG& gen)  // NOLINT
-      : mocked_gen_ptr_(MakeMockPointer(&gen)),
-        t_erased_gen_ptr_(reinterpret_cast<uintptr_t>(&gen)),
-        generate_impl_fn_(ImplFn<URBG>) {
-  }
+      : t_erased_gen_ptr_(reinterpret_cast<uintptr_t>(&gen)),
+        mock_call_(&MockCall<URBG>),
+        generate_impl_fn_(ImplFn<URBG>) {}
+
+  using result_type = uint64_t;
 
   static constexpr result_type(min)() {
     return (std::numeric_limits<result_type>::min)();
@@ -106,14 +137,9 @@ class BitGenRef {
   result_type operator()() { return generate_impl_fn_(t_erased_gen_ptr_); }
 
  private:
-  friend struct absl::random_internal::DistributionCaller<absl::BitGenRef>;
   using impl_fn = result_type (*)(uintptr_t);
-  using mocker_base_t = absl::random_internal::MockingBitGenBase;
-
-  // Convert an arbitrary URBG pointer into either a valid mocker_base_t
-  // pointer or a nullptr.
-  static inline mocker_base_t* MakeMockPointer(mocker_base_t* t) { return t; }
-  static inline mocker_base_t* MakeMockPointer(void*) { return nullptr; }
+  using mock_call_fn = bool (*)(uintptr_t, base_internal::FastTypeIdType, void*,
+                                void*);
 
   template <typename URBG>
   static result_type ImplFn(uintptr_t ptr) {
@@ -123,29 +149,32 @@ class BitGenRef {
     return fast_uniform_bits(*reinterpret_cast<URBG*>(ptr));
   }
 
-  mocker_base_t* mocked_gen_ptr_;
+  // Get a type-erased InvokeMock pointer.
+  template <typename URBG>
+  static bool MockCall(uintptr_t gen_ptr, base_internal::FastTypeIdType type,
+                       void* result, void* arg_tuple) {
+    return reinterpret_cast<URBG*>(gen_ptr)->InvokeMock(type, result,
+                                                        arg_tuple);
+  }
+  static bool NotAMock(uintptr_t, base_internal::FastTypeIdType, void*, void*) {
+    return false;
+  }
+
+  inline bool InvokeMock(base_internal::FastTypeIdType type, void* args_tuple,
+                         void* result) {
+    if (mock_call_ == NotAMock) return false;  // avoids an indirect call.
+    return mock_call_(t_erased_gen_ptr_, type, args_tuple, result);
+  }
+
   uintptr_t t_erased_gen_ptr_;
+  mock_call_fn mock_call_;
   impl_fn generate_impl_fn_;
-};
-
-namespace random_internal {
 
-template <>
-struct DistributionCaller<absl::BitGenRef> {
-  template <typename DistrT, typename... Args>
-  static typename DistrT::result_type Call(absl::BitGenRef* gen_ref,
-                                           Args&&... args) {
-    auto* mock_ptr = gen_ref->mocked_gen_ptr_;
-    if (mock_ptr == nullptr) {
-      DistrT dist(std::forward<Args>(args)...);
-      return dist(*gen_ref);
-    } else {
-      return mock_ptr->template Call<DistrT>(std::forward<Args>(args)...);
-    }
-  }
+  template <typename>
+  friend struct ::absl::random_internal::DistributionCaller;  // for InvokeMock
+  friend class ::absl::random_internal::MockHelpers;          // for InvokeMock
 };
 
-}  // namespace random_internal
 ABSL_NAMESPACE_END
 }  // namespace absl
 
diff --git a/third_party/abseil_cpp/absl/random/bit_gen_ref_test.cc b/third_party/abseil_cpp/absl/random/bit_gen_ref_test.cc
index ca0e4d707250..1135cf2da0bf 100644
--- a/third_party/abseil_cpp/absl/random/bit_gen_ref_test.cc
+++ b/third_party/abseil_cpp/absl/random/bit_gen_ref_test.cc
@@ -17,30 +17,31 @@
 
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
+#include "absl/base/internal/fast_type_id.h"
 #include "absl/random/internal/sequence_urbg.h"
 #include "absl/random/random.h"
 
 namespace absl {
 ABSL_NAMESPACE_BEGIN
 
-class ConstBitGen : public absl::random_internal::MockingBitGenBase {
-  bool CallImpl(const std::type_info&, void*, void* result) override {
+class ConstBitGen {
+ public:
+  // URBG interface
+  using result_type = absl::BitGen::result_type;
+
+  static constexpr result_type(min)() { return (absl::BitGen::min)(); }
+  static constexpr result_type(max)() { return (absl::BitGen::max)(); }
+  result_type operator()() { return 1; }
+
+  // InvokeMock method
+  bool InvokeMock(base_internal::FastTypeIdType index, void*, void* result) {
     *static_cast<int*>(result) = 42;
     return true;
   }
 };
 
-namespace random_internal {
-template <>
-struct DistributionCaller<ConstBitGen> {
-  template <typename DistrT, typename FormatT, typename... Args>
-  static typename DistrT::result_type Call(ConstBitGen* gen, Args&&... args) {
-    return gen->template Call<DistrT, FormatT>(std::forward<Args>(args)...);
-  }
-};
-}  // namespace random_internal
-
 namespace {
+
 int FnTest(absl::BitGenRef gen_ref) { return absl::Uniform(gen_ref, 1, 7); }
 
 template <typename T>
diff --git a/third_party/abseil_cpp/absl/random/distributions.h b/third_party/abseil_cpp/absl/random/distributions.h
index 8680f6a66f0a..6775c5d6ff23 100644
--- a/third_party/abseil_cpp/absl/random/distributions.h
+++ b/third_party/abseil_cpp/absl/random/distributions.h
@@ -57,7 +57,7 @@
 #include "absl/random/beta_distribution.h"
 #include "absl/random/exponential_distribution.h"
 #include "absl/random/gaussian_distribution.h"
-#include "absl/random/internal/distributions.h"  // IWYU pragma: export
+#include "absl/random/internal/distribution_caller.h"  // IWYU pragma: export
 #include "absl/random/internal/uniform_helper.h"  // IWYU pragma: export
 #include "absl/random/log_uniform_int_distribution.h"
 #include "absl/random/poisson_distribution.h"
diff --git a/third_party/abseil_cpp/absl/random/internal/BUILD.bazel b/third_party/abseil_cpp/absl/random/internal/BUILD.bazel
index 85d1fb81d23b..d81477ffb7e8 100644
--- a/third_party/abseil_cpp/absl/random/internal/BUILD.bazel
+++ b/third_party/abseil_cpp/absl/random/internal/BUILD.bazel
@@ -45,21 +45,10 @@ cc_library(
     hdrs = ["distribution_caller.h"],
     copts = ABSL_DEFAULT_COPTS,
     linkopts = ABSL_DEFAULT_LINKOPTS,
-    deps = ["//absl/base:config"],
-)
-
-cc_library(
-    name = "distributions",
-    hdrs = ["distributions.h"],
-    copts = ABSL_DEFAULT_COPTS,
-    linkopts = ABSL_DEFAULT_LINKOPTS,
     deps = [
-        ":distribution_caller",
-        ":traits",
-        ":uniform_helper",
-        "//absl/base",
-        "//absl/meta:type_traits",
-        "//absl/strings",
+        "//absl/base:config",
+        "//absl/base:fast_type_id",
+        "//absl/utility",
     ],
 )
 
@@ -221,7 +210,6 @@ cc_library(
         ":seed_material",
         "//absl/base:core_headers",
         "//absl/meta:type_traits",
-        "//absl/strings",
         "//absl/types:optional",
         "//absl/types:span",
     ],
@@ -497,12 +485,11 @@ cc_test(
 )
 
 cc_library(
-    name = "mocking_bit_gen_base",
-    hdrs = ["mocking_bit_gen_base.h"],
-    linkopts = ABSL_DEFAULT_LINKOPTS,
+    name = "mock_helpers",
+    hdrs = ["mock_helpers.h"],
     deps = [
-        "//absl/random",
-        "//absl/strings",
+        "//absl/base:fast_type_id",
+        "//absl/types:optional",
     ],
 )
 
@@ -511,6 +498,7 @@ cc_library(
     testonly = 1,
     hdrs = ["mock_overload_set.h"],
     deps = [
+        ":mock_helpers",
         "//absl/random:mocking_bit_gen",
         "@com_google_googletest//:gtest",
     ],
@@ -672,6 +660,8 @@ cc_library(
     copts = ABSL_DEFAULT_COPTS,
     linkopts = ABSL_DEFAULT_LINKOPTS,
     deps = [
+        ":traits",
+        "//absl/base:config",
         "//absl/meta:type_traits",
     ],
 )
diff --git a/third_party/abseil_cpp/absl/random/internal/distribution_caller.h b/third_party/abseil_cpp/absl/random/internal/distribution_caller.h
index 4e0724440cbc..fc81b787ebe2 100644
--- a/third_party/abseil_cpp/absl/random/internal/distribution_caller.h
+++ b/third_party/abseil_cpp/absl/random/internal/distribution_caller.h
@@ -20,6 +20,8 @@
 #include <utility>
 
 #include "absl/base/config.h"
+#include "absl/base/internal/fast_type_id.h"
+#include "absl/utility/utility.h"
 
 namespace absl {
 ABSL_NAMESPACE_BEGIN
@@ -30,14 +32,57 @@ namespace random_internal {
 // to intercept such calls.
 template <typename URBG>
 struct DistributionCaller {
-  // Call the provided distribution type. The parameters are expected
-  // to be explicitly specified.
-  // DistrT is the distribution type.
+  // SFINAE to detect whether the URBG type includes a member matching
+  // bool InvokeMock(base_internal::FastTypeIdType, void*, void*).
+  //
+  // These live inside BitGenRef so that they have friend access
+  // to MockingBitGen. (see similar methods in DistributionCaller).
+  template <template <class...> class Trait, class AlwaysVoid, class... Args>
+  struct detector : std::false_type {};
+  template <template <class...> class Trait, class... Args>
+  struct detector<Trait, absl::void_t<Trait<Args...>>, Args...>
+      : std::true_type {};
+
+  template <class T>
+  using invoke_mock_t = decltype(std::declval<T*>()->InvokeMock(
+      std::declval<::absl::base_internal::FastTypeIdType>(),
+      std::declval<void*>(), std::declval<void*>()));
+
+  using HasInvokeMock = typename detector<invoke_mock_t, void, URBG>::type;
+
+  // Default implementation of distribution caller.
   template <typename DistrT, typename... Args>
-  static typename DistrT::result_type Call(URBG* urbg, Args&&... args) {
+  static typename DistrT::result_type Impl(std::false_type, URBG* urbg,
+                                           Args&&... args) {
     DistrT dist(std::forward<Args>(args)...);
     return dist(*urbg);
   }
+
+  // Mock implementation of distribution caller.
+  // The underlying KeyT must match the KeyT constructed by MockOverloadSet.
+  template <typename DistrT, typename... Args>
+  static typename DistrT::result_type Impl(std::true_type, URBG* urbg,
+                                           Args&&... args) {
+    using ResultT = typename DistrT::result_type;
+    using ArgTupleT = std::tuple<absl::decay_t<Args>...>;
+    using KeyT = ResultT(DistrT, ArgTupleT);
+
+    ArgTupleT arg_tuple(std::forward<Args>(args)...);
+    ResultT result;
+    if (!urbg->InvokeMock(::absl::base_internal::FastTypeId<KeyT>(), &arg_tuple,
+                          &result)) {
+      auto dist = absl::make_from_tuple<DistrT>(arg_tuple);
+      result = dist(*urbg);
+    }
+    return result;
+  }
+
+  // Default implementation of distribution caller.
+  template <typename DistrT, typename... Args>
+  static typename DistrT::result_type Call(URBG* urbg, Args&&... args) {
+    return Impl<DistrT, Args...>(HasInvokeMock{}, urbg,
+                                 std::forward<Args>(args)...);
+  }
 };
 
 }  // namespace random_internal
diff --git a/third_party/abseil_cpp/absl/random/internal/distributions.h b/third_party/abseil_cpp/absl/random/internal/distributions.h
deleted file mode 100644
index d7e3c0161f06..000000000000
--- a/third_party/abseil_cpp/absl/random/internal/distributions.h
+++ /dev/null
@@ -1,52 +0,0 @@
-// Copyright 2019 The Abseil Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef ABSL_RANDOM_INTERNAL_DISTRIBUTIONS_H_
-#define ABSL_RANDOM_INTERNAL_DISTRIBUTIONS_H_
-
-#include <type_traits>
-
-#include "absl/meta/type_traits.h"
-#include "absl/random/internal/distribution_caller.h"
-#include "absl/random/internal/traits.h"
-#include "absl/random/internal/uniform_helper.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-namespace random_internal {
-
-// In the absence of an explicitly provided return-type, the template
-// "uniform_inferred_return_t<A, B>" is used to derive a suitable type, based on
-// the data-types of the endpoint-arguments {A lo, B hi}.
-//
-// Given endpoints {A lo, B hi}, one of {A, B} will be chosen as the
-// return-type, if one type can be implicitly converted into the other, in a
-// lossless way. The template "is_widening_convertible" implements the
-// compile-time logic for deciding if such a conversion is possible.
-//
-// If no such conversion between {A, B} exists, then the overload for
-// absl::Uniform() will be discarded, and the call will be ill-formed.
-// Return-type for absl::Uniform() when the return-type is inferred.
-template <typename A, typename B>
-using uniform_inferred_return_t =
-    absl::enable_if_t<absl::disjunction<is_widening_convertible<A, B>,
-                                        is_widening_convertible<B, A>>::value,
-                      typename std::conditional<
-                          is_widening_convertible<A, B>::value, B, A>::type>;
-
-}  // namespace random_internal
-ABSL_NAMESPACE_END
-}  // namespace absl
-
-#endif  // ABSL_RANDOM_INTERNAL_DISTRIBUTIONS_H_
diff --git a/third_party/abseil_cpp/absl/random/internal/mock_helpers.h b/third_party/abseil_cpp/absl/random/internal/mock_helpers.h
new file mode 100644
index 000000000000..9af27ab3a210
--- /dev/null
+++ b/third_party/abseil_cpp/absl/random/internal/mock_helpers.h
@@ -0,0 +1,127 @@
+//
+// Copyright 2019 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef ABSL_RANDOM_INTERNAL_MOCK_HELPERS_H_
+#define ABSL_RANDOM_INTERNAL_MOCK_HELPERS_H_
+
+#include <tuple>
+#include <type_traits>
+
+#include "absl/base/internal/fast_type_id.h"
+#include "absl/types/optional.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace random_internal {
+
+// MockHelpers works in conjunction with MockOverloadSet, MockingBitGen, and
+// BitGenRef to enable the mocking capability for absl distribution functions.
+//
+// MockingBitGen registers mocks based on the typeid of a mock signature, KeyT,
+// which is used to generate a unique id.
+//
+// KeyT is a signature of the form:
+//   result_type(discriminator_type, std::tuple<args...>)
+// The mocked function signature will be composed from KeyT as:
+//   result_type(args...)
+//
+class MockHelpers {
+  using IdType = ::absl::base_internal::FastTypeIdType;
+
+  // Given a key signature type used to index the mock, extract the components.
+  // KeyT is expected to have the form:
+  //   result_type(discriminator_type, arg_tuple_type)
+  template <typename KeyT>
+  struct KeySignature;
+
+  template <typename ResultT, typename DiscriminatorT, typename ArgTupleT>
+  struct KeySignature<ResultT(DiscriminatorT, ArgTupleT)> {
+    using result_type = ResultT;
+    using discriminator_type = DiscriminatorT;
+    using arg_tuple_type = ArgTupleT;
+  };
+
+  // Detector for InvokeMock.
+  template <class T>
+  using invoke_mock_t = decltype(std::declval<T*>()->InvokeMock(
+      std::declval<IdType>(), std::declval<void*>(), std::declval<void*>()));
+
+  // Empty implementation of InvokeMock.
+  template <typename KeyT, typename ReturnT, typename ArgTupleT, typename URBG,
+            typename... Args>
+  static absl::optional<ReturnT> InvokeMockImpl(char, URBG*, Args&&...) {
+    return absl::nullopt;
+  }
+
+  // Non-empty implementation of InvokeMock.
+  template <typename KeyT, typename ReturnT, typename ArgTupleT, typename URBG,
+            typename = invoke_mock_t<URBG>, typename... Args>
+  static absl::optional<ReturnT> InvokeMockImpl(int, URBG* urbg,
+                                                Args&&... args) {
+    ArgTupleT arg_tuple(std::forward<Args>(args)...);
+    ReturnT result;
+    if (urbg->InvokeMock(::absl::base_internal::FastTypeId<KeyT>(), &arg_tuple,
+                         &result)) {
+      return result;
+    }
+    return absl::nullopt;
+  }
+
+ public:
+  // Invoke a mock for the KeyT (may or may not be a signature).
+  //
+  // KeyT is used to generate a typeid-based lookup key for the mock.
+  // KeyT is a signature of the form:
+  //   result_type(discriminator_type, std::tuple<args...>)
+  // The mocked function signature will be composed from KeyT as:
+  //   result_type(args...)
+  //
+  // An instance of arg_tuple_type must be constructable from Args..., since
+  // the underlying mechanism requires a pointer to an argument tuple.
+  template <typename KeyT, typename URBG, typename... Args>
+  static auto MaybeInvokeMock(URBG* urbg, Args&&... args)
+      -> absl::optional<typename KeySignature<KeyT>::result_type> {
+    // Use function overloading to dispatch to the implemenation since
+    // more modern patterns (e.g. require + constexpr) are not supported in all
+    // compiler configurations.
+    return InvokeMockImpl<KeyT, typename KeySignature<KeyT>::result_type,
+                          typename KeySignature<KeyT>::arg_tuple_type, URBG>(
+        0, urbg, std::forward<Args>(args)...);
+  }
+
+  // Acquire a mock for the KeyT (may or may not be a signature).
+  //
+  // KeyT is used to generate a typeid-based lookup for the mock.
+  // KeyT is a signature of the form:
+  //   result_type(discriminator_type, std::tuple<args...>)
+  // The mocked function signature will be composed from KeyT as:
+  //   result_type(args...)
+  template <typename KeyT, typename MockURBG>
+  static auto MockFor(MockURBG& m) -> decltype(
+      std::declval<MockURBG>()
+          .template RegisterMock<typename KeySignature<KeyT>::result_type,
+                                 typename KeySignature<KeyT>::arg_tuple_type>(
+              std::declval<IdType>())) {
+    return m.template RegisterMock<typename KeySignature<KeyT>::result_type,
+                                   typename KeySignature<KeyT>::arg_tuple_type>(
+        ::absl::base_internal::FastTypeId<KeyT>());
+  }
+};
+
+}  // namespace random_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_RANDOM_INTERNAL_MOCK_HELPERS_H_
diff --git a/third_party/abseil_cpp/absl/random/internal/mock_overload_set.h b/third_party/abseil_cpp/absl/random/internal/mock_overload_set.h
index c2a30d89d52b..dccc6cee679c 100644
--- a/third_party/abseil_cpp/absl/random/internal/mock_overload_set.h
+++ b/third_party/abseil_cpp/absl/random/internal/mock_overload_set.h
@@ -20,6 +20,7 @@
 
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
+#include "absl/random/internal/mock_helpers.h"
 #include "absl/random/mocking_bit_gen.h"
 
 namespace absl {
@@ -35,17 +36,20 @@ struct MockSingleOverload;
 // EXPECT_CALL(mock_single_overload, Call(...))` will expand to a call to
 // `mock_single_overload.gmock_Call(...)`. Because expectations are stored on
 // the MockingBitGen (an argument passed inside `Call(...)`), this forwards to
-// arguments to Mocking::Register.
+// arguments to MockingBitGen::Register.
+//
+// The underlying KeyT must match the KeyT constructed by DistributionCaller.
 template <typename DistrT, typename Ret, typename... Args>
 struct MockSingleOverload<DistrT, Ret(MockingBitGen&, Args...)> {
   static_assert(std::is_same<typename DistrT::result_type, Ret>::value,
                 "Overload signature must have return type matching the "
-                "distributions result type.");
+                "distribution result_type.");
+  using KeyT = Ret(DistrT, std::tuple<Args...>);
   auto gmock_Call(
       absl::MockingBitGen& gen,  // NOLINT(google-runtime-references)
-      const ::testing::Matcher<Args>&... args)
-      -> decltype(gen.Register<DistrT, Args...>(args...)) {
-    return gen.Register<DistrT, Args...>(args...);
+      const ::testing::Matcher<Args>&... matchers)
+      -> decltype(MockHelpers::MockFor<KeyT>(gen).gmock_Call(matchers...)) {
+    return MockHelpers::MockFor<KeyT>(gen).gmock_Call(matchers...);
   }
 };
 
@@ -53,13 +57,15 @@ template <typename DistrT, typename Ret, typename Arg, typename... Args>
 struct MockSingleOverload<DistrT, Ret(Arg, MockingBitGen&, Args...)> {
   static_assert(std::is_same<typename DistrT::result_type, Ret>::value,
                 "Overload signature must have return type matching the "
-                "distributions result type.");
+                "distribution result_type.");
+  using KeyT = Ret(DistrT, std::tuple<Arg, Args...>);
   auto gmock_Call(
-      const ::testing::Matcher<Arg>& arg,
+      const ::testing::Matcher<Arg>& matcher,
       absl::MockingBitGen& gen,  // NOLINT(google-runtime-references)
-      const ::testing::Matcher<Args>&... args)
-      -> decltype(gen.Register<DistrT, Arg, Args...>(arg, args...)) {
-    return gen.Register<DistrT, Arg, Args...>(arg, args...);
+      const ::testing::Matcher<Args>&... matchers)
+      -> decltype(MockHelpers::MockFor<KeyT>(gen).gmock_Call(matcher,
+                                                             matchers...)) {
+    return MockHelpers::MockFor<KeyT>(gen).gmock_Call(matcher, matchers...);
   }
 };
 
diff --git a/third_party/abseil_cpp/absl/random/internal/mocking_bit_gen_base.h b/third_party/abseil_cpp/absl/random/internal/mocking_bit_gen_base.h
deleted file mode 100644
index 23ecaf6c7e63..000000000000
--- a/third_party/abseil_cpp/absl/random/internal/mocking_bit_gen_base.h
+++ /dev/null
@@ -1,85 +0,0 @@
-//
-// Copyright 2018 The Abseil Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-#ifndef ABSL_RANDOM_INTERNAL_MOCKING_BIT_GEN_BASE_H_
-#define ABSL_RANDOM_INTERNAL_MOCKING_BIT_GEN_BASE_H_
-
-#include <string>
-#include <typeinfo>
-
-#include "absl/random/random.h"
-#include "absl/strings/str_cat.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-namespace random_internal {
-
-class MockingBitGenBase {
-  template <typename>
-  friend struct DistributionCaller;
-  using generator_type = absl::BitGen;
-
- public:
-  // URBG interface
-  using result_type = generator_type::result_type;
-  static constexpr result_type(min)() { return (generator_type::min)(); }
-  static constexpr result_type(max)() { return (generator_type::max)(); }
-  result_type operator()() { return gen_(); }
-
-  virtual ~MockingBitGenBase() = default;
-
- protected:
-  // CallImpl is the type-erased virtual dispatch.
-  // The type of dist is always distribution<T>,
-  // The type of result is always distribution<T>::result_type.
-  virtual bool CallImpl(const std::type_info& distr_type, void* dist_args,
-                        void* result) = 0;
-
-  template <typename DistrT, typename ArgTupleT>
-  static const std::type_info& GetTypeId() {
-    return typeid(std::pair<absl::decay_t<DistrT>, absl::decay_t<ArgTupleT>>);
-  }
-
-  // Call the generating distribution function.
-  // Invoked by DistributionCaller<>::Call<DistT>.
-  // DistT is the distribution type.
-  template <typename DistrT, typename... Args>
-  typename DistrT::result_type Call(Args&&... args) {
-    using distr_result_type = typename DistrT::result_type;
-    using ArgTupleT = std::tuple<absl::decay_t<Args>...>;
-
-    ArgTupleT arg_tuple(std::forward<Args>(args)...);
-    auto dist = absl::make_from_tuple<DistrT>(arg_tuple);
-
-    distr_result_type result{};
-    bool found_match =
-        CallImpl(GetTypeId<DistrT, ArgTupleT>(), &arg_tuple, &result);
-
-    if (!found_match) {
-      result = dist(gen_);
-    }
-
-    return result;
-  }
-
- private:
-  generator_type gen_;
-};  // namespace random_internal
-
-}  // namespace random_internal
-ABSL_NAMESPACE_END
-}  // namespace absl
-
-#endif  // ABSL_RANDOM_INTERNAL_MOCKING_BIT_GEN_BASE_H_
diff --git a/third_party/abseil_cpp/absl/random/internal/uniform_helper.h b/third_party/abseil_cpp/absl/random/internal/uniform_helper.h
index 663107cb3a63..5b2afecb89e6 100644
--- a/third_party/abseil_cpp/absl/random/internal/uniform_helper.h
+++ b/third_party/abseil_cpp/absl/random/internal/uniform_helper.h
@@ -19,10 +19,13 @@
 #include <limits>
 #include <type_traits>
 
+#include "absl/base/config.h"
 #include "absl/meta/type_traits.h"
+#include "absl/random/internal/traits.h"
 
 namespace absl {
 ABSL_NAMESPACE_BEGIN
+
 template <typename IntType>
 class uniform_int_distribution;
 
@@ -58,6 +61,26 @@ struct IntervalOpenOpenTag
     : public random_internal::TagTypeCompare<IntervalOpenOpenTag> {};
 
 namespace random_internal {
+
+// In the absence of an explicitly provided return-type, the template
+// "uniform_inferred_return_t<A, B>" is used to derive a suitable type, based on
+// the data-types of the endpoint-arguments {A lo, B hi}.
+//
+// Given endpoints {A lo, B hi}, one of {A, B} will be chosen as the
+// return-type, if one type can be implicitly converted into the other, in a
+// lossless way. The template "is_widening_convertible" implements the
+// compile-time logic for deciding if such a conversion is possible.
+//
+// If no such conversion between {A, B} exists, then the overload for
+// absl::Uniform() will be discarded, and the call will be ill-formed.
+// Return-type for absl::Uniform() when the return-type is inferred.
+template <typename A, typename B>
+using uniform_inferred_return_t =
+    absl::enable_if_t<absl::disjunction<is_widening_convertible<A, B>,
+                                        is_widening_convertible<B, A>>::value,
+                      typename std::conditional<
+                          is_widening_convertible<A, B>::value, B, A>::type>;
+
 // The functions
 //    uniform_lower_bound(tag, a, b)
 // and
@@ -149,12 +172,19 @@ uniform_upper_bound(Tag, FloatType, FloatType b) {
   return std::nextafter(b, (std::numeric_limits<FloatType>::max)());
 }
 
+// UniformDistribution selects either absl::uniform_int_distribution
+// or absl::uniform_real_distribution depending on the NumType parameter.
 template <typename NumType>
 using UniformDistribution =
     typename std::conditional<std::is_integral<NumType>::value,
                               absl::uniform_int_distribution<NumType>,
                               absl::uniform_real_distribution<NumType>>::type;
 
+// UniformDistributionWrapper is used as the underlying distribution type
+// by the absl::Uniform template function. It selects the proper Abseil
+// uniform distribution and provides constructor overloads that match the
+// expected parameter order as well as adjusting distribtuion bounds based
+// on the tag.
 template <typename NumType>
 struct UniformDistributionWrapper : public UniformDistribution<NumType> {
   template <typename TagType>
diff --git a/third_party/abseil_cpp/absl/random/mock_distributions.h b/third_party/abseil_cpp/absl/random/mock_distributions.h
index d36d5ba03cab..764ab370abeb 100644
--- a/third_party/abseil_cpp/absl/random/mock_distributions.h
+++ b/third_party/abseil_cpp/absl/random/mock_distributions.h
@@ -27,6 +27,11 @@
 // More information about the Googletest testing framework is available at
 // https://github.com/google/googletest
 //
+// EXPECT_CALL and ON_CALL need to be made within the same DLL component as
+// the call to absl::Uniform and related methods, otherwise mocking will fail
+// since the  underlying implementation creates a type-specific pointer which
+// will be distinct across different DLL boundaries.
+//
 // Example:
 //
 //   absl::MockingBitGen mock;
diff --git a/third_party/abseil_cpp/absl/random/mocking_bit_gen.h b/third_party/abseil_cpp/absl/random/mocking_bit_gen.h
index 3d8a979e734f..6d2f2c836245 100644
--- a/third_party/abseil_cpp/absl/random/mocking_bit_gen.h
+++ b/third_party/abseil_cpp/absl/random/mocking_bit_gen.h
@@ -33,17 +33,16 @@
 #include <memory>
 #include <tuple>
 #include <type_traits>
-#include <typeindex>
-#include <typeinfo>
 #include <utility>
 
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
+#include "absl/base/internal/fast_type_id.h"
 #include "absl/container/flat_hash_map.h"
 #include "absl/meta/type_traits.h"
 #include "absl/random/distributions.h"
 #include "absl/random/internal/distribution_caller.h"
-#include "absl/random/internal/mocking_bit_gen_base.h"
+#include "absl/random/random.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/str_join.h"
 #include "absl/types/span.h"
@@ -54,11 +53,12 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 
 namespace random_internal {
-
-template <typename, typename>
-struct MockSingleOverload;
+template <typename>
+struct DistributionCaller;
+class MockHelpers;
 
 }  // namespace random_internal
+class BitGenRef;
 
 // MockingBitGen
 //
@@ -96,102 +96,132 @@ struct MockSingleOverload;
 // At this time, only mock distributions supplied within the Abseil random
 // library are officially supported.
 //
-class MockingBitGen : public absl::random_internal::MockingBitGenBase {
+// EXPECT_CALL and ON_CALL need to be made within the same DLL component as
+// the call to absl::Uniform and related methods, otherwise mocking will fail
+// since the  underlying implementation creates a type-specific pointer which
+// will be distinct across different DLL boundaries.
+//
+class MockingBitGen {
  public:
-  MockingBitGen() {}
+  MockingBitGen() = default;
 
-  ~MockingBitGen() override {
+  ~MockingBitGen() {
     for (const auto& del : deleters_) del();
   }
 
+  // URBG interface
+  using result_type = absl::BitGen::result_type;
+
+  static constexpr result_type(min)() { return (absl::BitGen::min)(); }
+  static constexpr result_type(max)() { return (absl::BitGen::max)(); }
+  result_type operator()() { return gen_(); }
+
  private:
-  template <typename DistrT, typename... Args>
-  using MockFnType =
-      ::testing::MockFunction<typename DistrT::result_type(Args...)>;
+  using match_impl_fn = void (*)(void* mock_fn, void* t_erased_arg_tuple,
+                                 void* t_erased_result);
+
+  struct MockData {
+    void* mock_fn = nullptr;
+    match_impl_fn match_impl = nullptr;
+  };
+
+  // GetMockFnType returns the testing::MockFunction for a result and tuple.
+  // This method only exists for type deduction and is otherwise unimplemented.
+  template <typename ResultT, typename... Args>
+  static auto GetMockFnType(ResultT, std::tuple<Args...>)
+      -> ::testing::MockFunction<ResultT(Args...)>;
+
+  // MockFnCaller is a helper method for use with absl::apply to
+  // apply an ArgTupleT to a compatible MockFunction.
+  // NOTE: MockFnCaller is essentially equivalent to the lambda:
+  // [fn](auto... args) { return fn->Call(std::move(args)...)}
+  // however that fails to build on some supported platforms.
+  template <typename ResultT, typename MockFnType, typename Tuple>
+  struct MockFnCaller;
+  // specialization for std::tuple.
+  template <typename ResultT, typename MockFnType, typename... Args>
+  struct MockFnCaller<ResultT, MockFnType, std::tuple<Args...>> {
+    MockFnType* fn;
+    inline ResultT operator()(Args... args) {
+      return fn->Call(std::move(args)...);
+    }
+  };
 
-  // MockingBitGen::Register
+  // MockingBitGen::RegisterMock
   //
-  // Register<DistrT, FormatT, ArgTupleT> is the main extension point for
-  // extending the MockingBitGen framework. It provides a mechanism to install a
-  // mock expectation for the distribution `distr_t` onto the MockingBitGen
-  // context.
+  // RegisterMock<ResultT, ArgTupleT>(FastTypeIdType) is the main extension
+  // point for extending the MockingBitGen framework. It provides a mechanism to
+  // install a mock expectation for a function like ResultT(Args...) keyed by
+  // type_idex onto the MockingBitGen context. The key is that the type_index
+  // used to register must match the type index used to call the mock.
   //
   // The returned MockFunction<...> type can be used to setup additional
   // distribution parameters of the expectation.
-  template <typename DistrT, typename... Args, typename... Ms>
-  decltype(std::declval<MockFnType<DistrT, Args...>>().gmock_Call(
-      std::declval<Ms>()...))
-  Register(Ms&&... matchers) {
-    auto& mock =
-        mocks_[std::type_index(GetTypeId<DistrT, std::tuple<Args...>>())];
-
+  template <typename ResultT, typename ArgTupleT>
+  auto RegisterMock(base_internal::FastTypeIdType type)
+      -> decltype(GetMockFnType(std::declval<ResultT>(),
+                                std::declval<ArgTupleT>()))& {
+    using MockFnType = decltype(
+        GetMockFnType(std::declval<ResultT>(), std::declval<ArgTupleT>()));
+    auto& mock = mocks_[type];
     if (!mock.mock_fn) {
-      auto* mock_fn = new MockFnType<DistrT, Args...>;
+      auto* mock_fn = new MockFnType;
       mock.mock_fn = mock_fn;
-      mock.match_impl = &MatchImpl<DistrT, Args...>;
+      mock.match_impl = &MatchImpl<ResultT, ArgTupleT>;
       deleters_.emplace_back([mock_fn] { delete mock_fn; });
     }
-
-    return static_cast<MockFnType<DistrT, Args...>*>(mock.mock_fn)
-        ->gmock_Call(std::forward<Ms>(matchers)...);
+    return *static_cast<MockFnType*>(mock.mock_fn);
   }
 
-  mutable std::vector<std::function<void()>> deleters_;
-
-  using match_impl_fn = void (*)(void* mock_fn, void* t_erased_dist_args,
-                                 void* t_erased_result);
-  struct MockData {
-    void* mock_fn = nullptr;
-    match_impl_fn match_impl = nullptr;
-  };
-
-  mutable absl::flat_hash_map<std::type_index, MockData> mocks_;
-
-  template <typename DistrT, typename... Args>
-  static void MatchImpl(void* mock_fn, void* dist_args, void* result) {
-    using result_type = typename DistrT::result_type;
-    *static_cast<result_type*>(result) = absl::apply(
-        [mock_fn](Args... args) -> result_type {
-          return (*static_cast<MockFnType<DistrT, Args...>*>(mock_fn))
-              .Call(std::move(args)...);
-        },
-        *static_cast<std::tuple<Args...>*>(dist_args));
+  // MockingBitGen::MatchImpl<> is a dispatch function which converts the
+  // generic type-erased parameters into a specific mock invocation call.
+  // Requires tuple_args to point to a ArgTupleT, which is a std::tuple<Args...>
+  // used to invoke the mock function.
+  // Requires result to point to a ResultT, which is the result of the call.
+  template <typename ResultT, typename ArgTupleT>
+  static void MatchImpl(/*MockFnType<ResultT, Args...>*/ void* mock_fn,
+                        /*ArgTupleT*/ void* args_tuple,
+                        /*ResultT*/ void* result) {
+    using MockFnType = decltype(
+        GetMockFnType(std::declval<ResultT>(), std::declval<ArgTupleT>()));
+    *static_cast<ResultT*>(result) = absl::apply(
+        MockFnCaller<ResultT, MockFnType, ArgTupleT>{
+            static_cast<MockFnType*>(mock_fn)},
+        *static_cast<ArgTupleT*>(args_tuple));
   }
 
-  // Looks for an appropriate mock - Returns the mocked result if one is found.
-  // Otherwise, returns a random value generated by the underlying URBG.
-  bool CallImpl(const std::type_info& key_type, void* dist_args,
-                void* result) override {
+  // MockingBitGen::InvokeMock
+  //
+  // InvokeMock(FastTypeIdType, args, result) is the entrypoint for invoking
+  // mocks registered on MockingBitGen.
+  //
+  // When no mocks are registered on the provided FastTypeIdType, returns false.
+  // Otherwise attempts to invoke the mock function ResultT(Args...) that
+  // was previously registered via the type_index.
+  // Requires tuple_args to point to a ArgTupleT, which is a std::tuple<Args...>
+  // used to invoke the mock function.
+  // Requires result to point to a ResultT, which is the result of the call.
+  inline bool InvokeMock(base_internal::FastTypeIdType type, void* args_tuple,
+                         void* result) {
     // Trigger a mock, if there exists one that matches `param`.
-    auto it = mocks_.find(std::type_index(key_type));
+    auto it = mocks_.find(type);
     if (it == mocks_.end()) return false;
     auto* mock_data = static_cast<MockData*>(&it->second);
-    mock_data->match_impl(mock_data->mock_fn, dist_args, result);
+    mock_data->match_impl(mock_data->mock_fn, args_tuple, result);
     return true;
   }
 
-  template <typename, typename>
-  friend struct ::absl::random_internal::MockSingleOverload;
-  friend struct ::absl::random_internal::DistributionCaller<
-      absl::MockingBitGen>;
-};
-
-// -----------------------------------------------------------------------------
-// Implementation Details Only Below
-// -----------------------------------------------------------------------------
+  absl::flat_hash_map<base_internal::FastTypeIdType, MockData> mocks_;
+  std::vector<std::function<void()>> deleters_;
+  absl::BitGen gen_;
 
-namespace random_internal {
-
-template <>
-struct DistributionCaller<absl::MockingBitGen> {
-  template <typename DistrT, typename... Args>
-  static typename DistrT::result_type Call(absl::MockingBitGen* gen,
-                                           Args&&... args) {
-    return gen->template Call<DistrT>(std::forward<Args>(args)...);
-  }
+  template <typename>
+  friend struct ::absl::random_internal::DistributionCaller;  // for InvokeMock
+  friend class ::absl::BitGenRef;                             // for InvokeMock
+  friend class ::absl::random_internal::MockHelpers;  // for RegisterMock,
+                                                      // InvokeMock
 };
 
-}  // namespace random_internal
 ABSL_NAMESPACE_END
 }  // namespace absl
 
diff --git a/third_party/abseil_cpp/absl/random/seed_sequences_test.cc b/third_party/abseil_cpp/absl/random/seed_sequences_test.cc
index 2cc8b0e6f2b7..fe1100bda0d5 100644
--- a/third_party/abseil_cpp/absl/random/seed_sequences_test.cc
+++ b/third_party/abseil_cpp/absl/random/seed_sequences_test.cc
@@ -96,7 +96,6 @@ template <typename URBG>
 void TestReproducibleVariateSequencesForNonsecureURBG() {
   const size_t kNumVariates = 1000;
 
-  // Master RNG instance.
   URBG rng;
   // Reused for both RNG instances.
   auto reusable_seed = absl::CreateSeedSeqFrom(&rng);