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 // Copyright 2007, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
 // in the documentation and/or other materials provided with the
 // distribution.
 //     * Neither the name of Google Inc. nor the names of its
 // contributors may be used to endorse or promote products derived from
 // this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Google Mock - a framework for writing C++ mock classes.
 //
 // The ACTION* family of macros can be used in a namespace scope to
 // define custom actions easily.  The syntax:
 //
 //   ACTION(name) { statements; }
 //
 // will define an action with the given name that executes the
 // statements.  The value returned by the statements will be used as
 // the return value of the action.  Inside the statements, you can
 // refer to the K-th (0-based) argument of the mock function by
 // 'argK', and refer to its type by 'argK_type'.  For example:
 //
 //   ACTION(IncrementArg1) {
 //     arg1_type temp = arg1;
 //     return ++(*temp);
 //   }
 //
 // allows you to write
 //
 //   ...WillOnce(IncrementArg1());
 //
 // You can also refer to the entire argument tuple and its type by
 // 'args' and 'args_type', and refer to the mock function type and its
 // return type by 'function_type' and 'return_type'.
 //
 // Note that you don't need to specify the types of the mock function
 // arguments.  However rest assured that your code is still type-safe:
 // you'll get a compiler error if *arg1 doesn't support the ++
 // operator, or if the type of ++(*arg1) isn't compatible with the
 // mock function's return type, for example.
 //
 // Sometimes you'll want to parameterize the action.   For that you can use
 // another macro:
 //
 //   ACTION_P(name, param_name) { statements; }
 //
 // For example:
 //
 //   ACTION_P(Add, n) { return arg0 + n; }
 //
 // will allow you to write:
 //
 //   ...WillOnce(Add(5));
 //
 // Note that you don't need to provide the type of the parameter
 // either.  If you need to reference the type of a parameter named
 // 'foo', you can write 'foo_type'.  For example, in the body of
 // ACTION_P(Add, n) above, you can write 'n_type' to refer to the type
 // of 'n'.
 //
 // We also provide ACTION_P2, ACTION_P3, ..., up to ACTION_P10 to support
 // multi-parameter actions.
 //
 // For the purpose of typing, you can view
 //
 //   ACTION_Pk(Foo, p1, ..., pk) { ... }
 //
 // as shorthand for
 //
 //   template <typename p1_type, ..., typename pk_type>
 //   FooActionPk<p1_type, ..., pk_type> Foo(p1_type p1, ..., pk_type pk) { ... }
 //
 // In particular, you can provide the template type arguments
 // explicitly when invoking Foo(), as in Foo<long, bool>(5, false);
 // although usually you can rely on the compiler to infer the types
 // for you automatically.  You can assign the result of expression
 // Foo(p1, ..., pk) to a variable of type FooActionPk<p1_type, ...,
 // pk_type>.  This can be useful when composing actions.
 //
 // You can also overload actions with different numbers of parameters:
 //
 //   ACTION_P(Plus, a) { ... }
 //   ACTION_P2(Plus, a, b) { ... }
 //
 // While it's tempting to always use the ACTION* macros when defining
 // a new action, you should also consider implementing ActionInterface
 // or using MakePolymorphicAction() instead, especially if you need to
 // use the action a lot.  While these approaches require more work,
 // they give you more control on the types of the mock function
 // arguments and the action parameters, which in general leads to
 // better compiler error messages that pay off in the long run.  They
 // also allow overloading actions based on parameter types (as opposed
 // to just based on the number of parameters).
 //
 // CAVEAT:
 //
 // ACTION*() can only be used in a namespace scope as templates cannot be
 // declared inside of a local class.
 // Users can, however, define any local functors (e.g. a lambda) that
 // can be used as actions.
 //
 // MORE INFORMATION:
 //
 // To learn more about using these macros, please search for 'ACTION' on
 // https://github.com/google/googletest/blob/main/docs/gmock_cook_book.md
 
 // IWYU pragma: private, include "gmock/gmock.h"
 // IWYU pragma: friend gmock/.*
 
 #ifndef GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
 #define GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
 
 #ifndef _WIN32_WCE
 #include <errno.h>
 #endif
 
 #include <algorithm>
 #include <exception>
 #include <functional>
 #include <memory>
 #include <string>
 #include <tuple>
 #include <type_traits>
 #include <utility>
 
 #include "gmock/internal/gmock-internal-utils.h"
 #include "gmock/internal/gmock-port.h"
 #include "gmock/internal/gmock-pp.h"
 
 GTEST_DISABLE_MSC_WARNINGS_PUSH_(4100)
 
 namespace testing {
 
 // To implement an action Foo, define:
 //   1. a class FooAction that implements the ActionInterface interface, and
 //   2. a factory function that creates an Action object from a
 //      const FooAction*.
 //
 // The two-level delegation design follows that of Matcher, providing
 // consistency for extension developers.  It also eases ownership
 // management as Action objects can now be copied like plain values.
 
 namespace internal {
 
 // BuiltInDefaultValueGetter<T, true>::Get() returns a
 // default-constructed T value.  BuiltInDefaultValueGetter<T,
 // false>::Get() crashes with an error.
 //
 // This primary template is used when kDefaultConstructible is true.
 template <typename T, bool kDefaultConstructible>
 struct BuiltInDefaultValueGetter {
   static T Get() { return T(); }
 };
 template <typename T>
 struct BuiltInDefaultValueGetter<T, false> {
   static T Get() {
     Assert(false, __FILE__, __LINE__,
            "Default action undefined for the function return type.");
 #if defined(__GNUC__) || defined(__clang__)
     __builtin_unreachable();
 #elif defined(_MSC_VER)
     __assume(0);
 #else
     return Invalid<T>();
     // The above statement will never be reached, but is required in
     // order for this function to compile.
 #endif
   }
 };
 
 // BuiltInDefaultValue<T>::Get() returns the "built-in" default value
 // for type T, which is NULL when T is a raw pointer type, 0 when T is
 // a numeric type, false when T is bool, or "" when T is string or
 // std::string.  In addition, in C++11 and above, it turns a
 // default-constructed T value if T is default constructible.  For any
 // other type T, the built-in default T value is undefined, and the
 // function will abort the process.
 template <typename T>
 class [[nodiscard]] BuiltInDefaultValue {
  public:
   // This function returns true if and only if type T has a built-in default
   // value.
   static bool Exists() { return ::std::is_default_constructible<T>::value; }
 
   static T Get() {
     return BuiltInDefaultValueGetter<
         T, ::std::is_default_constructible<T>::value>::Get();
   }
 };
 
 // This partial specialization says that we use the same built-in
 // default value for T and const T.
 template <typename T>
 class [[nodiscard]] BuiltInDefaultValue<const T> {
  public:
   static bool Exists() { return BuiltInDefaultValue<T>::Exists(); }
   static T Get() { return BuiltInDefaultValue<T>::Get(); }
 };
 
 // This partial specialization defines the default values for pointer
 // types.
 template <typename T>
 class [[nodiscard]] BuiltInDefaultValue<T*> {
  public:
   static bool Exists() { return true; }
   static T* Get() { return nullptr; }
 };
 
 // The following specializations define the default values for
 // specific types we care about.
 #define GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(type, value) \
   template <>                                                     \
   class BuiltInDefaultValue<type> {                               \
    public:                                                        \
     static bool Exists() { return true; }                         \
     static type Get() { return value; }                           \
   }
 
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(void, );  // NOLINT
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(::std::string, "");
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(bool, false);
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned char, '\0');
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed char, '\0');
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(char, '\0');
 
 // There's no need for a default action for signed wchar_t, as that
 // type is the same as wchar_t for gcc, and invalid for MSVC.
 //
 // There's also no need for a default action for unsigned wchar_t, as
 // that type is the same as unsigned int for gcc, and invalid for
 // MSVC.
 #if GMOCK_WCHAR_T_IS_NATIVE_
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(wchar_t, 0U);  // NOLINT
 #endif
 
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned short, 0U);  // NOLINT
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed short, 0);     // NOLINT
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned int, 0U);
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed int, 0);
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned long, 0UL);     // NOLINT
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed long, 0L);        // NOLINT
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned long long, 0);  // NOLINT
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed long long, 0);    // NOLINT
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(float, 0);
 GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(double, 0);
 
 #undef GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_
 
 // Partial implementations of metaprogramming types from the standard library
 // not available in C++11.
 
 template <typename P>
 struct negation
     // NOLINTNEXTLINE
     : std::integral_constant<bool, bool(!P::value)> {};
 
 // Base case: with zero predicates the answer is always true.
 template <typename...>
 struct conjunction : std::true_type {};
 
 // With a single predicate, the answer is that predicate.
 template <typename P1>
 struct conjunction<P1> : P1 {};
 
 // With multiple predicates the answer is the first predicate if that is false,
 // and we recurse otherwise.
 template <typename P1, typename... Ps>
 struct conjunction<P1, Ps...>
     : std::conditional<bool(P1::value), conjunction<Ps...>, P1>::type {};
 
 template <typename...>
 struct disjunction : std::false_type {};
 
 template <typename P1>
 struct disjunction<P1> : P1 {};
 
 template <typename P1, typename... Ps>
 struct disjunction<P1, Ps...>
     // NOLINTNEXTLINE
     : std::conditional<!bool(P1::value), disjunction<Ps...>, P1>::type {};
 
 template <typename...>
 using void_t = void;
 
 // Detects whether an expression of type `From` can be implicitly converted to
 // `To` according to [conv]. In C++17, [conv]/3 defines this as follows:
 //
 //     An expression e can be implicitly converted to a type T if and only if
 //     the declaration T t=e; is well-formed, for some invented temporary
 //     variable t ([dcl.init]).
 //
 // [conv]/2 implies we can use function argument passing to detect whether this
 // initialization is valid.
 //
 // Note that this is distinct from is_convertible, which requires this be valid:
 //
 //     To test() {
 //       return declval<From>();
 //     }
 //
 // In particular, is_convertible doesn't give the correct answer when `To` and
 // `From` are the same non-moveable type since `declval<From>` will be an rvalue
 // reference, defeating the guaranteed copy elision that would otherwise make
 // this function work.
 //
 // REQUIRES: `From` is not cv void.
 template <typename From, typename To>
 struct is_implicitly_convertible {
  private:
   // A function that accepts a parameter of type T. This can be called with type
   // U successfully only if U is implicitly convertible to T.
   template <typename T>
   static void Accept(T);
 
   // A function that creates a value of type T.
   template <typename T>
   static T Make();
 
   // An overload be selected when implicit conversion from T to To is possible.
   template <typename T, typename = decltype(Accept<To>(Make<T>()))>
   static std::true_type TestImplicitConversion(int);
 
   // A fallback overload selected in all other cases.
   template <typename T>
   static std::false_type TestImplicitConversion(...);
 
  public:
   using type = decltype(TestImplicitConversion<From>(0));
   static constexpr bool value = type::value;
 };
 
 // Like std::invoke_result_t from C++17, but works only for objects with call
 // operators (not e.g. member function pointers, which we don't need specific
 // support for in OnceAction because std::function deals with them).
 template <typename F, typename... Args>
 using call_result_t = decltype(std::declval<F>()(std::declval<Args>()...));
 
 template <typename Void, typename R, typename F, typename... Args>
 struct is_callable_r_impl : std::false_type {};
 
 // Specialize the struct for those template arguments where call_result_t is
 // well-formed. When it's not, the generic template above is chosen, resulting
 // in std::false_type.
 template <typename R, typename F, typename... Args>
 struct is_callable_r_impl<void_t<call_result_t<F, Args...>>, R, F, Args...>
     : std::conditional<
           std::is_void<R>::value,  //
           std::true_type,          //
           is_implicitly_convertible<call_result_t<F, Args...>, R>>::type {};
 
 // Like std::is_invocable_r from C++17, but works only for objects with call
 // operators. See the note on call_result_t.
 template <typename R, typename F, typename... Args>
 using is_callable_r = is_callable_r_impl<void, R, F, Args...>;
 
 // Like std::as_const from C++17.
 template <typename T>
 typename std::add_const<T>::type& as_const(T& t) {
   return t;
 }
 
 }  // namespace internal
 
 // Specialized for function types below.
 template <typename F>
 class [[nodiscard]] OnceAction;
 
 // An action that can only be used once.
 //
 // This is accepted by WillOnce, which doesn't require the underlying action to
 // be copy-constructible (only move-constructible), and promises to invoke it as
 // an rvalue reference. This allows the action to work with move-only types like
 // std::move_only_function in a type-safe manner.
 //
 // For example:
 //
 //     // Assume we have some API that needs to accept a unique pointer to some
 //     // non-copyable object Foo.
 //     void AcceptUniquePointer(std::unique_ptr<Foo> foo);
 //
 //     // We can define an action that provides a Foo to that API. Because It
 //     // has to give away its unique pointer, it must not be called more than
 //     // once, so its call operator is &&-qualified.
 //     struct ProvideFoo {
 //       std::unique_ptr<Foo> foo;
 //
 //       void operator()() && {
 //         AcceptUniquePointer(std::move(Foo));
 //       }
 //     };
 //
 //     // This action can be used with WillOnce.
 //     EXPECT_CALL(mock, Call)
 //         .WillOnce(ProvideFoo{std::make_unique<Foo>(...)});
 //
 //     // But a call to WillRepeatedly will fail to compile. This is correct,
 //     // since the action cannot correctly be used repeatedly.
 //     EXPECT_CALL(mock, Call)
 //         .WillRepeatedly(ProvideFoo{std::make_unique<Foo>(...)});
 //
 // A less-contrived example would be an action that returns an arbitrary type,
 // whose &&-qualified call operator is capable of dealing with move-only types.
 template <typename Result, typename... Args>
 class [[nodiscard]] OnceAction<Result(Args...)> final {
  private:
   // True iff we can use the given callable type (or lvalue reference) directly
   // via StdFunctionAdaptor.
   template <typename Callable>
   using IsDirectlyCompatible = internal::conjunction<
       // The callable must be compatible with our signature.
       internal::is_callable_r<Result, std::decay_t<Callable>, Args...>,
       // It must be possible to capture the callable in StdFunctionAdaptor.
       std::is_constructible<std::decay_t<Callable>, Callable>>;
 
   // True iff we can use the given callable type via StdFunctionAdaptor once we
   // ignore incoming arguments.
   template <typename Callable>
   using IsCompatibleAfterIgnoringArguments = internal::conjunction<
       // The callable must be invocable with zero arguments, returning something
       // convertible to Result.
       internal::is_callable_r<Result, std::decay_t<Callable>>,
       // It must be possible to capture the callable in a lambda.
       std::is_constructible<std::decay_t<Callable>, Callable>>;
 
  public:
   // Construct from a callable that is directly compatible with our mocked
   // signature: it accepts our function type's arguments and returns something
   // convertible to our result type.
   template <typename Callable,
             typename std::enable_if<
                 internal::conjunction<
                     // Teach clang on macOS that we're not talking about a
                     // copy/move constructor here. Otherwise it gets confused
                     // when checking the is_constructible requirement of our
                     // traits above.
                     internal::negation<std::is_same<
                         OnceAction, typename std::decay<Callable>::type>>,
                     IsDirectlyCompatible<Callable>>  //
                 ::value,
                 int>::type = 0>
   OnceAction(Callable&& callable)  // NOLINT
       : function_(StdFunctionAdaptor<typename std::decay<Callable>::type>(
             {}, std::forward<Callable>(callable))) {}
 
   // As above, but for a callable that ignores the mocked function's arguments.
   template <typename Callable,
             typename std::enable_if<
                 internal::conjunction<
                     // Teach clang on macOS that we're not talking about a
                     // copy/move constructor here. Otherwise it gets confused
                     // when checking the is_constructible requirement of our
                     // traits above.
                     internal::negation<std::is_same<
                         OnceAction, typename std::decay<Callable>::type>>,
                     // Exclude callables for which the overload above works.
                     // We'd rather provide the arguments if possible.
                     internal::negation<IsDirectlyCompatible<Callable>>,
                     IsCompatibleAfterIgnoringArguments<Callable>>::value,
                 int>::type = 0>
   OnceAction(Callable&& callable)  // NOLINT
                                    // Call the constructor above with a callable
                                    // that ignores the input arguments.
       : OnceAction(IgnoreIncomingArguments<typename std::decay<Callable>::type>{
             std::forward<Callable>(callable)}) {}
 
   // We are naturally copyable because we store only an std::function, but
   // semantically we should not be copyable.
   OnceAction(const OnceAction&) = delete;
   OnceAction& operator=(const OnceAction&) = delete;
   OnceAction(OnceAction&&) = default;
 
   // Invoke the underlying action callable with which we were constructed,
   // handing it the supplied arguments.
   Result Call(Args... args) && {
     return function_(std::forward<Args>(args)...);
   }
 
  private:
   // An adaptor that wraps a callable that is compatible with our signature and
   // being invoked as an rvalue reference so that it can be used as an
   // StdFunctionAdaptor. This throws away type safety, but that's fine because
   // this is only used by WillOnce, which we know calls at most once.
   //
   // Once we have something like std::move_only_function from C++23, we can do
   // away with this.
   template <typename Callable>
   class StdFunctionAdaptor final {
    public:
     // A tag indicating that the (otherwise universal) constructor is accepting
     // the callable itself, instead of e.g. stealing calls for the move
     // constructor.
     struct CallableTag final {};
 
     template <typename F>
     explicit StdFunctionAdaptor(CallableTag, F&& callable)
         : callable_(std::make_shared<Callable>(std::forward<F>(callable))) {}
 
     // Rather than explicitly returning Result, we return whatever the wrapped
     // callable returns. This allows for compatibility with existing uses like
     // the following, when the mocked function returns void:
     //
     //     EXPECT_CALL(mock_fn_, Call)
     //         .WillOnce([&] {
     //            [...]
     //            return 0;
     //         });
     //
     // Such a callable can be turned into std::function<void()>. If we use an
     // explicit return type of Result here then it *doesn't* work with
     // std::function, because we'll get a "void function should not return a
     // value" error.
     //
     // We need not worry about incompatible result types because the SFINAE on
     // OnceAction already checks this for us. std::is_invocable_r_v itself makes
     // the same allowance for void result types.
     template <typename... ArgRefs>
     internal::call_result_t<Callable, ArgRefs...> operator()(
         ArgRefs&&... args) const {
       return std::move(*callable_)(std::forward<ArgRefs>(args)...);
     }
 
    private:
     // We must put the callable on the heap so that we are copyable, which
     // std::function needs.
     std::shared_ptr<Callable> callable_;
   };
 
   // An adaptor that makes a callable that accepts zero arguments callable with
   // our mocked arguments.
   template <typename Callable>
   struct IgnoreIncomingArguments {
     internal::call_result_t<Callable> operator()(Args&&...) {
       return std::move(callable)();
     }
 
     Callable callable;
   };
 
   std::function<Result(Args...)> function_;
 };
 
 // When an unexpected function call is encountered, Google Mock will
 // let it return a default value if the user has specified one for its
 // return type, or if the return type has a built-in default value;
 // otherwise Google Mock won't know what value to return and will have
 // to abort the process.
 //
 // The DefaultValue<T> class allows a user to specify the
 // default value for a type T that is both copyable and publicly
 // destructible (i.e. anything that can be used as a function return
 // type).  The usage is:
 //
 //   // Sets the default value for type T to be foo.
 //   DefaultValue<T>::Set(foo);
 template <typename T>
 class [[nodiscard]] DefaultValue {
  public:
   // Sets the default value for type T; requires T to be
   // copy-constructable and have a public destructor.
   static void Set(T x) {
     delete producer_;
     producer_ = new FixedValueProducer(x);
   }
 
   // Provides a factory function to be called to generate the default value.
   // This method can be used even if T is only move-constructible, but it is not
   // limited to that case.
   typedef T (*FactoryFunction)();
   static void SetFactory(FactoryFunction factory) {
     delete producer_;
     producer_ = new FactoryValueProducer(factory);
   }
 
   // Unsets the default value for type T.
   static void Clear() {
     delete producer_;
     producer_ = nullptr;
   }
 
   // Returns true if and only if the user has set the default value for type T.
   static bool IsSet() { return producer_ != nullptr; }
 
   // Returns true if T has a default return value set by the user or there
   // exists a built-in default value.
   static bool Exists() {
     return IsSet() || internal::BuiltInDefaultValue<T>::Exists();
   }
 
   // Returns the default value for type T if the user has set one;
   // otherwise returns the built-in default value. Requires that Exists()
   // is true, which ensures that the return value is well-defined.
   static T Get() {
     return producer_ == nullptr ? internal::BuiltInDefaultValue<T>::Get()
                                 : producer_->Produce();
   }
 
  private:
   class ValueProducer {
    public:
     virtual ~ValueProducer() = default;
     virtual T Produce() = 0;
   };
 
   class FixedValueProducer : public ValueProducer {
    public:
     explicit FixedValueProducer(T value) : value_(value) {}
     T Produce() override { return value_; }
 
    private:
     const T value_;
     FixedValueProducer(const FixedValueProducer&) = delete;
     FixedValueProducer& operator=(const FixedValueProducer&) = delete;
   };
 
   class FactoryValueProducer : public ValueProducer {
    public:
     explicit FactoryValueProducer(FactoryFunction factory)
         : factory_(factory) {}
     T Produce() override { return factory_(); }
 
    private:
     const FactoryFunction factory_;
     FactoryValueProducer(const FactoryValueProducer&) = delete;
     FactoryValueProducer& operator=(const FactoryValueProducer&) = delete;
   };
 
   static ValueProducer* producer_;
 };
 
 // This partial specialization allows a user to set default values for
 // reference types.
 template <typename T>
 class [[nodiscard]] DefaultValue<T&> {
  public:
   // Sets the default value for type T&.
   static void Set(T& x) {  // NOLINT
     address_ = &x;
   }
 
   // Unsets the default value for type T&.
   static void Clear() { address_ = nullptr; }
 
   // Returns true if and only if the user has set the default value for type T&.
   static bool IsSet() { return address_ != nullptr; }
 
   // Returns true if T has a default return value set by the user or there
   // exists a built-in default value.
   static bool Exists() {
     return IsSet() || internal::BuiltInDefaultValue<T&>::Exists();
   }
 
   // Returns the default value for type T& if the user has set one;
   // otherwise returns the built-in default value if there is one;
   // otherwise aborts the process.
   static T& Get() {
     return address_ == nullptr ? internal::BuiltInDefaultValue<T&>::Get()
                                : *address_;
   }
 
  private:
   static T* address_;
 };
 
 // This specialization allows DefaultValue<void>::Get() to
 // compile.
 template <>
 class [[nodiscard]] DefaultValue<void> {
  public:
   static bool Exists() { return true; }
   static void Get() {}
 };
 
 // Points to the user-set default value for type T.
 template <typename T>
 typename DefaultValue<T>::ValueProducer* DefaultValue<T>::producer_ = nullptr;
 
 // Points to the user-set default value for type T&.
 template <typename T>
 T* DefaultValue<T&>::address_ = nullptr;
 
 // Implement this interface to define an action for function type F.
 template <typename F>
 class [[nodiscard]] ActionInterface {
  public:
   typedef typename internal::Function<F>::Result Result;
   typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
 
   ActionInterface() = default;
   virtual ~ActionInterface() = default;
 
   // Performs the action.  This method is not const, as in general an
   // action can have side effects and be stateful.  For example, a
   // get-the-next-element-from-the-collection action will need to
   // remember the current element.
   virtual Result Perform(const ArgumentTuple& args) = 0;
 
  private:
   ActionInterface(const ActionInterface&) = delete;
   ActionInterface& operator=(const ActionInterface&) = delete;
 };
 
 template <typename F>
 class [[nodiscard]] Action;
 
 // An Action<R(Args...)> is a copyable and IMMUTABLE (except by assignment)
 // object that represents an action to be taken when a mock function of type
 // R(Args...) is called. The implementation of Action<T> is just a
 // std::shared_ptr to const ActionInterface<T>. Don't inherit from Action! You
 // can view an object implementing ActionInterface<F> as a concrete action
 // (including its current state), and an Action<F> object as a handle to it.
 template <typename R, typename... Args>
 class [[nodiscard]] Action<R(Args...)> {
  private:
   using F = R(Args...);
 
   // Adapter class to allow constructing Action from a legacy ActionInterface.
   // New code should create Actions from functors instead.
   struct ActionAdapter {
     // Adapter must be copyable to satisfy std::function requirements.
     ::std::shared_ptr<ActionInterface<F>> impl_;
 
     template <typename... InArgs>
     typename internal::Function<F>::Result operator()(InArgs&&... args) {
       return impl_->Perform(
           ::std::forward_as_tuple(::std::forward<InArgs>(args)...));
     }
   };
 
   template <typename G>
   using IsCompatibleFunctor = std::is_constructible<std::function<F>, G>;
 
  public:
   typedef typename internal::Function<F>::Result Result;
   typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
 
   // Constructs a null Action.  Needed for storing Action objects in
   // STL containers.
   Action() = default;
 
   // Construct an Action from a specified callable.
   // This cannot take std::function directly, because then Action would not be
   // directly constructible from lambda (it would require two conversions).
   template <
       typename G,
       typename = typename std::enable_if<internal::disjunction<
           IsCompatibleFunctor<G>, std::is_constructible<std::function<Result()>,
                                                         G>>::value>::type>
   Action(G&& fun) {  // NOLINT
     Init(::std::forward<G>(fun), IsCompatibleFunctor<G>());
   }
 
   // Constructs an Action from its implementation.
   explicit Action(ActionInterface<F>* impl)
       : fun_(ActionAdapter{::std::shared_ptr<ActionInterface<F>>(impl)}) {}
 
   // This constructor allows us to turn an Action<Func> object into an
   // Action<F>, as long as F's arguments can be implicitly converted
   // to Func's and Func's return type can be implicitly converted to F's.
   template <typename Func>
   Action(const Action<Func>& action)  // NOLINT
       : fun_(action.fun_) {}
 
   // Returns true if and only if this is the DoDefault() action.
   bool IsDoDefault() const { return fun_ == nullptr; }
 
   // Performs the action.  Note that this method is const even though
   // the corresponding method in ActionInterface is not.  The reason
   // is that a const Action<F> means that it cannot be re-bound to
   // another concrete action, not that the concrete action it binds to
   // cannot change state.  (Think of the difference between a const
   // pointer and a pointer to const.)
   Result Perform(ArgumentTuple args) const {
     if (IsDoDefault()) {
       internal::IllegalDoDefault(__FILE__, __LINE__);
     }
     return internal::Apply(fun_, ::std::move(args));
   }
 
   // An action can be used as a OnceAction, since it's obviously safe to call it
   // once.
   operator OnceAction<F>() const {  // NOLINT
     // Return a OnceAction-compatible callable that calls Perform with the
     // arguments it is provided. We could instead just return fun_, but then
     // we'd need to handle the IsDoDefault() case separately.
     struct OA {
       Action<F> action;
 
       R operator()(Args... args) && {
         return action.Perform(
             std::forward_as_tuple(std::forward<Args>(args)...));
       }
     };
 
     return OA{*this};
   }
 
  private:
   template <typename G>
   friend class Action;
 
   template <typename G>
   void Init(G&& g, ::std::true_type) {
     fun_ = ::std::forward<G>(g);
   }
 
   template <typename G>
   void Init(G&& g, ::std::false_type) {
     fun_ = IgnoreArgs<typename ::std::decay<G>::type>{::std::forward<G>(g)};
   }
 
   template <typename FunctionImpl>
   struct IgnoreArgs {
     template <typename... InArgs>
     Result operator()(const InArgs&...) const {
       return function_impl();
     }
     template <typename... InArgs>
     Result operator()(const InArgs&...) {
       return function_impl();
     }
 
     FunctionImpl function_impl;
   };
 
   // fun_ is an empty function if and only if this is the DoDefault() action.
   ::std::function<F> fun_;
 };
 
 // The PolymorphicAction class template makes it easy to implement a
 // polymorphic action (i.e. an action that can be used in mock
 // functions of than one type, e.g. Return()).
 //
 // To define a polymorphic action, a user first provides a COPYABLE
 // implementation class that has a Perform() method template:
 //
 //   class FooAction {
 //    public:
 //     template <typename Result, typename ArgumentTuple>
 //     Result Perform(const ArgumentTuple& args) const {
 //       // Processes the arguments and returns a result, using
 //       // std::get<N>(args) to get the N-th (0-based) argument in the tuple.
 //     }
 //     ...
 //   };
 //
 // Then the user creates the polymorphic action using
 // MakePolymorphicAction(object) where object has type FooAction.  See
 // the definition of Return(void) and SetArgumentPointee<N>(value) for
 // complete examples.
 template <typename Impl>
 class [[nodiscard]] PolymorphicAction {
  public:
   explicit PolymorphicAction(const Impl& impl) : impl_(impl) {}
 
   template <typename F>
   operator Action<F>() const {
     return Action<F>(new MonomorphicImpl<F>(impl_));
   }
 
  private:
   template <typename F>
   class MonomorphicImpl : public ActionInterface<F> {
    public:
     typedef typename internal::Function<F>::Result Result;
     typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
 
     explicit MonomorphicImpl(const Impl& impl) : impl_(impl) {}
 
     Result Perform(const ArgumentTuple& args) override {
       return impl_.template Perform<Result>(args);
     }
 
    private:
     Impl impl_;
   };
 
   Impl impl_;
 };
 
 // Creates an Action from its implementation and returns it.  The
 // created Action object owns the implementation.
 template <typename F>
 Action<F> MakeAction(ActionInterface<F>* impl) {
   return Action<F>(impl);
 }
 
 // Creates a polymorphic action from its implementation.  This is
 // easier to use than the PolymorphicAction<Impl> constructor as it
 // doesn't require you to explicitly write the template argument, e.g.
 //
 //   MakePolymorphicAction(foo);
 // vs
 //   PolymorphicAction<TypeOfFoo>(foo);
 template <typename Impl>
 inline PolymorphicAction<Impl> MakePolymorphicAction(const Impl& impl) {
   return PolymorphicAction<Impl>(impl);
 }
 
 namespace internal {
 
 // Helper struct to specialize ReturnAction to execute a move instead of a copy
 // on return. Useful for move-only types, but could be used on any type.
 template <typename T>
 struct ByMoveWrapper {
   explicit ByMoveWrapper(T value) : payload(std::move(value)) {}
   T payload;
 };
 
 // The general implementation of Return(R). Specializations follow below.
 template <typename R>
 class [[nodiscard]] ReturnAction final {
  public:
   explicit ReturnAction(R value) : value_(std::move(value)) {}
 
   template <typename U, typename... Args,
             typename = typename std::enable_if<conjunction<
                 // See the requirements documented on Return.
                 negation<std::is_same<void, U>>,  //
                 negation<std::is_reference<U>>,   //
                 std::is_convertible<R, U>,        //
                 std::is_move_constructible<U>>::value>::type>
   operator OnceAction<U(Args...)>() && {  // NOLINT
     return Impl<U>(std::move(value_));
   }
 
   template <typename U, typename... Args,
             typename = typename std::enable_if<conjunction<
                 // See the requirements documented on Return.
                 negation<std::is_same<void, U>>,   //
                 negation<std::is_reference<U>>,    //
                 std::is_convertible<const R&, U>,  //
                 std::is_copy_constructible<U>>::value>::type>
   operator Action<U(Args...)>() const {  // NOLINT
     return Impl<U>(value_);
   }
 
  private:
   // Implements the Return(x) action for a mock function that returns type U.
   template <typename U>
   class Impl final {
    public:
     // The constructor used when the return value is allowed to move from the
     // input value (i.e. we are converting to OnceAction).
     explicit Impl(R&& input_value)
         : state_(new State(std::move(input_value))) {}
 
     // The constructor used when the return value is not allowed to move from
     // the input value (i.e. we are converting to Action).
     explicit Impl(const R& input_value) : state_(new State(input_value)) {}
 
     U operator()() && { return std::move(state_->value); }
     U operator()() const& { return state_->value; }
 
    private:
     // We put our state on the heap so that the compiler-generated copy/move
     // constructors work correctly even when U is a reference-like type. This is
     // necessary only because we eagerly create State::value (see the note on
     // that symbol for details). If we instead had only the input value as a
     // member then the default constructors would work fine.
     //
     // For example, when R is std::string and U is std::string_view, value is a
     // reference to the string backed by input_value. The copy constructor would
     // copy both, so that we wind up with a new input_value object (with the
     // same contents) and a reference to the *old* input_value object rather
     // than the new one.
     struct State {
       explicit State(const R& input_value_in)
           : input_value(input_value_in),
             // Make an implicit conversion to Result before initializing the U
             // object we store, avoiding calling any explicit constructor of U
             // from R.
             //
             // This simulates the language rules: a function with return type U
             // that does `return R()` requires R to be implicitly convertible to
             // U, and uses that path for the conversion, even U Result has an
             // explicit constructor from R.
             value(ImplicitCast_<U>(internal::as_const(input_value))) {}
 
       // As above, but for the case where we're moving from the ReturnAction
       // object because it's being used as a OnceAction.
       explicit State(R&& input_value_in)
           : input_value(std::move(input_value_in)),
             // For the same reason as above we make an implicit conversion to U
             // before initializing the value.
             //
             // Unlike above we provide the input value as an rvalue to the
             // implicit conversion because this is a OnceAction: it's fine if it
             // wants to consume the input value.
             value(ImplicitCast_<U>(std::move(input_value))) {}
 
       // A copy of the value originally provided by the user. We retain this in
       // addition to the value of the mock function's result type below in case
       // the latter is a reference-like type. See the std::string_view example
       // in the documentation on Return.
       R input_value;
 
       // The value we actually return, as the type returned by the mock function
       // itself.
       //
       // We eagerly initialize this here, rather than lazily doing the implicit
       // conversion automatically each time Perform is called, for historical
       // reasons: in 2009-11, commit a070cbd91c (Google changelist 13540126)
       // made the Action<U()> conversion operator eagerly convert the R value to
       // U, but without keeping the R alive. This broke the use case discussed
       // in the documentation for Return, making reference-like types such as
       // std::string_view not safe to use as U where the input type R is a
       // value-like type such as std::string.
       //
       // The example the commit gave was not very clear, nor was the issue
       // thread (https://github.com/google/googlemock/issues/86), but it seems
       // the worry was about reference-like input types R that flatten to a
       // value-like type U when being implicitly converted. An example of this
       // is std::vector<bool>::reference, which is often a proxy type with an
       // reference to the underlying vector:
       //
       //     // Helper method: have the mock function return bools according
       //     // to the supplied script.
       //     void SetActions(MockFunction<bool(size_t)>& mock,
       //                     const std::vector<bool>& script) {
       //       for (size_t i = 0; i < script.size(); ++i) {
       //         EXPECT_CALL(mock, Call(i)).WillOnce(Return(script[i]));
       //       }
       //     }
       //
       //     TEST(Foo, Bar) {
       //       // Set actions using a temporary vector, whose operator[]
       //       // returns proxy objects that references that will be
       //       // dangling once the call to SetActions finishes and the
       //       // vector is destroyed.
       //       MockFunction<bool(size_t)> mock;
       //       SetActions(mock, {false, true});
       //
       //       EXPECT_FALSE(mock.AsStdFunction()(0));
       //       EXPECT_TRUE(mock.AsStdFunction()(1));
       //     }
       //
       // This eager conversion helps with a simple case like this, but doesn't
       // fully make these types work in general. For example the following still
       // uses a dangling reference:
       //
       //     TEST(Foo, Baz) {
       //       MockFunction<std::vector<std::string>()> mock;
       //
       //       // Return the same vector twice, and then the empty vector
       //       // thereafter.
       //       auto action = Return(std::initializer_list<std::string>{
       //           "taco", "burrito",
       //       });
       //
       //       EXPECT_CALL(mock, Call)
       //           .WillOnce(action)
       //           .WillOnce(action)
       //           .WillRepeatedly(Return(std::vector<std::string>{}));
       //
       //       EXPECT_THAT(mock.AsStdFunction()(),
       //                   ElementsAre("taco", "burrito"));
       //       EXPECT_THAT(mock.AsStdFunction()(),
       //                   ElementsAre("taco", "burrito"));
       //       EXPECT_THAT(mock.AsStdFunction()(), IsEmpty());
       //     }
       //
       U value;
     };
 
     const std::shared_ptr<State> state_;
   };
 
   R value_;
 };
 
 // A specialization of ReturnAction<R> when R is ByMoveWrapper<T> for some T.
 //
 // This version applies the type system-defeating hack of moving from T even in
 // the const call operator, checking at runtime that it isn't called more than
 // once, since the user has declared their intent to do so by using ByMove.
 template <typename T>
 class [[nodiscard]] ReturnAction<ByMoveWrapper<T>> final {
  public:
   explicit ReturnAction(ByMoveWrapper<T> wrapper)
       : state_(new State(std::move(wrapper.payload))) {}
 
   T operator()() const {
     GTEST_CHECK_(!state_->called)
         << "A ByMove() action must be performed at most once.";
 
     state_->called = true;
     return std::move(state_->value);
   }
 
  private:
   // We store our state on the heap so that we are copyable as required by
   // Action, despite the fact that we are stateful and T may not be copyable.
   struct State {
     explicit State(T&& value_in) : value(std::move(value_in)) {}
 
     T value;
     bool called = false;
   };
 
   const std::shared_ptr<State> state_;
 };
 
 // Implements the ReturnNull() action.
 class [[nodiscard]] ReturnNullAction {
  public:
   // Allows ReturnNull() to be used in any pointer-returning function. In C++11
   // this is enforced by returning nullptr, and in non-C++11 by asserting a
   // pointer type on compile time.
   template <typename Result, typename ArgumentTuple>
   static Result Perform(const ArgumentTuple&) {
     return nullptr;
   }
 };
 
 // Implements the Return() action.
 class [[nodiscard]] ReturnVoidAction {
  public:
   // Allows Return() to be used in any void-returning function.
   template <typename Result, typename ArgumentTuple>
   static void Perform(const ArgumentTuple&) {
     static_assert(std::is_void<Result>::value, "Result should be void.");
   }
 };
 
 // Implements the polymorphic ReturnRef(x) action, which can be used
 // in any function that returns a reference to the type of x,
 // regardless of the argument types.
 template <typename T>
 class [[nodiscard]] ReturnRefAction {
  public:
   // Constructs a ReturnRefAction object from the reference to be returned.
   explicit ReturnRefAction(T& ref) : ref_(ref) {}  // NOLINT
 
   // This template type conversion operator allows ReturnRef(x) to be
   // used in ANY function that returns a reference to x's type.
   template <typename F>
   operator Action<F>() const {
     typedef typename Function<F>::Result Result;
     // Asserts that the function return type is a reference.  This
     // catches the user error of using ReturnRef(x) when Return(x)
     // should be used, and generates some helpful error message.
     static_assert(std::is_reference<Result>::value,
                   "use Return instead of ReturnRef to return a value");
     return Action<F>(new Impl<F>(ref_));
   }
 
  private:
   // Implements the ReturnRef(x) action for a particular function type F.
   template <typename F>
   class Impl : public ActionInterface<F> {
    public:
     typedef typename Function<F>::Result Result;
     typedef typename Function<F>::ArgumentTuple ArgumentTuple;
 
     explicit Impl(T& ref) : ref_(ref) {}  // NOLINT
 
     Result Perform(const ArgumentTuple&) override { return ref_; }
 
    private:
     T& ref_;
   };
 
   T& ref_;
 };
 
 // Implements the polymorphic ReturnRefOfCopy(x) action, which can be
 // used in any function that returns a reference to the type of x,
 // regardless of the argument types.
 template <typename T>
 class [[nodiscard]] ReturnRefOfCopyAction {
  public:
   // Constructs a ReturnRefOfCopyAction object from the reference to
   // be returned.
   explicit ReturnRefOfCopyAction(const T& value) : value_(value) {}  // NOLINT
 
   // This template type conversion operator allows ReturnRefOfCopy(x) to be
   // used in ANY function that returns a reference to x's type.
   template <typename F>
   operator Action<F>() const {
     typedef typename Function<F>::Result Result;
     // Asserts that the function return type is a reference.  This
     // catches the user error of using ReturnRefOfCopy(x) when Return(x)
     // should be used, and generates some helpful error message.
     static_assert(std::is_reference<Result>::value,
                   "use Return instead of ReturnRefOfCopy to return a value");
     return Action<F>(new Impl<F>(value_));
   }
 
  private:
   // Implements the ReturnRefOfCopy(x) action for a particular function type F.
   template <typename F>
   class Impl : public ActionInterface<F> {
    public:
     typedef typename Function<F>::Result Result;
     typedef typename Function<F>::ArgumentTuple ArgumentTuple;
 
     explicit Impl(const T& value) : value_(value) {}  // NOLINT
 
     Result Perform(const ArgumentTuple&) override { return value_; }
 
    private:
     T value_;
   };
 
   const T value_;
 };
 
 // Implements the polymorphic ReturnRoundRobin(v) action, which can be
 // used in any function that returns the element_type of v.
 template <typename T>
 class [[nodiscard]] ReturnRoundRobinAction {
  public:
   explicit ReturnRoundRobinAction(std::vector<T> values) {
     GTEST_CHECK_(!values.empty())
         << "ReturnRoundRobin requires at least one element.";
     state_->values = std::move(values);
   }
 
   template <typename... Args>
   T operator()(Args&&...) const {
     return state_->Next();
   }
 
  private:
   struct State {
     T Next() {
       T ret_val = values[i++];
       if (i == values.size()) i = 0;
       return ret_val;
     }
 
     std::vector<T> values;
     size_t i = 0;
   };
   std::shared_ptr<State> state_ = std::make_shared<State>();
 };
 
 // Implements the polymorphic DoDefault() action.
 class [[nodiscard]] DoDefaultAction {
  public:
   // This template type conversion operator allows DoDefault() to be
   // used in any function.
   template <typename F>
   operator Action<F>() const {
     return Action<F>();
   }  // NOLINT
 };
 
 // Implements the Assign action to set a given pointer referent to a
 // particular value.
 template <typename T1, typename T2>
 class [[nodiscard]] AssignAction {
  public:
   AssignAction(T1* ptr, T2 value) : ptr_(ptr), value_(value) {}
 
   template <typename Result, typename ArgumentTuple>
   void Perform(const ArgumentTuple& /* args */) const {
     *ptr_ = value_;
   }
 
  private:
   T1* const ptr_;
   const T2 value_;
 };
 
 #ifndef GTEST_OS_WINDOWS_MOBILE
 
 // Implements the SetErrnoAndReturn action to simulate return from
 // various system calls and libc functions.
 template <typename T>
 class [[nodiscard]] SetErrnoAndReturnAction {
  public:
   SetErrnoAndReturnAction(int errno_value, T result)
       : errno_(errno_value), result_(result) {}
   template <typename Result, typename ArgumentTuple>
   Result Perform(const ArgumentTuple& /* args */) const {
     errno = errno_;
     return result_;
   }
 
  private:
   const int errno_;
   const T result_;
 };
 
 #endif  // !GTEST_OS_WINDOWS_MOBILE
 
 // Implements the SetArgumentPointee<N>(x) action for any function
 // whose N-th argument (0-based) is a pointer to x's type.
 template <size_t N, typename A, typename = void>
 struct SetArgumentPointeeAction {
   A value;
 
   template <typename... Args>
   void operator()(const Args&... args) const {
     *::std::get<N>(std::tie(args...)) = value;
   }
 };
 
 // Implements the Invoke(object_ptr, &Class::Method) action.
 template <class Class, typename MethodPtr>
 struct InvokeMethodAction {
   Class* const obj_ptr;
   const MethodPtr method_ptr;
 
   template <typename... Args>
   auto operator()(Args&&... args) const
       -> decltype((obj_ptr->*method_ptr)(std::forward<Args>(args)...)) {
     return (obj_ptr->*method_ptr)(std::forward<Args>(args)...);
   }
 };
 
 // Implements the InvokeWithoutArgs(object_ptr, &Class::Method) action.
 template <class Class, typename MethodPtr>
 struct InvokeMethodWithoutArgsAction {
   Class* const obj_ptr;
   const MethodPtr method_ptr;
 
   using ReturnType =
       decltype((std::declval<Class*>()->*std::declval<MethodPtr>())());
 
   template <typename... Args>
   ReturnType operator()(const Args&...) const {
     return (obj_ptr->*method_ptr)();
   }
 };
 
 // Implements the IgnoreResult(action) action.
 template <typename A>
 class IgnoreResultAction {
  public:
   explicit IgnoreResultAction(const A& action) : action_(action) {}
 
   template <typename F>
   operator Action<F>() const {
     // Assert statement belongs here because this is the best place to verify
     // conditions on F. It produces the clearest error messages
     // in most compilers.
     // Impl really belongs in this scope as a local class but can't
     // because MSVC produces duplicate symbols in different translation units
     // in this case. Until MS fixes that bug we put Impl into the class scope
     // and put the typedef both here (for use in assert statement) and
     // in the Impl class. But both definitions must be the same.
     typedef typename internal::Function<F>::Result Result;
 
     // Asserts at compile time that F returns void.
     static_assert(std::is_void<Result>::value, "Result type should be void.");
 
     return Action<F>(new Impl<F>(action_));
   }
 
  private:
   template <typename F>
   class Impl : public ActionInterface<F> {
    public:
     typedef typename internal::Function<F>::Result Result;
     typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
 
     explicit Impl(const A& action) : action_(action) {}
 
     void Perform(const ArgumentTuple& args) override {
       // Performs the action and ignores its result.
       (void)action_.Perform(args);
     }
 
    private:
     // Type OriginalFunction is the same as F except that its return
     // type is IgnoredValue.
     typedef
         typename internal::Function<F>::MakeResultIgnoredValue OriginalFunction;
 
     const Action<OriginalFunction> action_;
   };
 
   const A action_;
 };
 
 template <typename InnerAction, size_t... I>
 struct WithArgsAction {
   InnerAction inner_action;
 
   // The signature of the function as seen by the inner action, given an out
   // action with the given result and argument types.
   template <typename R, typename... Args>
   using InnerSignature =
       R(typename std::tuple_element<I, std::tuple<Args...>>::type...);
 
   // Rather than a call operator, we must define conversion operators to
   // particular action types. This is necessary for embedded actions like
   // DoDefault(), which rely on an action conversion operators rather than
   // providing a call operator because even with a particular set of arguments
   // they don't have a fixed return type.
 
   template <
       typename R, typename... Args,
       typename std::enable_if<
           std::is_convertible<InnerAction,
                               // Unfortunately we can't use the InnerSignature
                               // alias here; MSVC complains about the I
                               // parameter pack not being expanded (error C3520)
                               // despite it being expanded in the type alias.
                               // TupleElement is also an MSVC workaround.
                               // See its definition for details.
                               OnceAction<R(internal::TupleElement<
                                            I, std::tuple<Args...>>...)>>::value,
           int>::type = 0>
   operator OnceAction<R(Args...)>() && {  // NOLINT
     struct OA {
       OnceAction<InnerSignature<R, Args...>> inner_action;
 
       R operator()(Args&&... args) && {
         return std::move(inner_action)
             .Call(std::get<I>(
                 std::forward_as_tuple(std::forward<Args>(args)...))...);
       }
     };
 
     return OA{std::move(inner_action)};
   }
 
   // As above, but in the case where we want to create a OnceAction from a const
   // WithArgsAction. This is fine as long as the inner action doesn't need to
   // move any of its state to create a OnceAction.
   template <
       typename R, typename... Args,
       typename std::enable_if<
           std::is_convertible<const InnerAction&,
                               OnceAction<R(internal::TupleElement<
                                            I, std::tuple<Args...>>...)>>::value,
           int>::type = 0>
   operator OnceAction<R(Args...)>() const& {  // NOLINT
     struct OA {
       OnceAction<InnerSignature<R, Args...>> inner_action;
 
       R operator()(Args&&... args) && {
         return std::move(inner_action)
             .Call(std::get<I>(
                 std::forward_as_tuple(std::forward<Args>(args)...))...);
       }
     };
 
     return OA{inner_action};
   }
 
   template <
       typename R, typename... Args,
       typename std::enable_if<
           std::is_convertible<const InnerAction&,
                               // Unfortunately we can't use the InnerSignature
                               // alias here; MSVC complains about the I
                               // parameter pack not being expanded (error C3520)
                               // despite it being expanded in the type alias.
                               // TupleElement is also an MSVC workaround.
                               // See its definition for details.
                               Action<R(internal::TupleElement<
                                        I, std::tuple<Args...>>...)>>::value,
           int>::type = 0>
   operator Action<R(Args...)>() const {  // NOLINT
     Action<InnerSignature<R, Args...>> converted(inner_action);
 
     return [converted](Args&&... args) -> R {
       return converted.Perform(std::forward_as_tuple(
           std::get<I>(std::forward_as_tuple(std::forward<Args>(args)...))...));
     };
   }
 };
 
 template <typename... Actions>
 class [[nodiscard]] DoAllAction;
 
 // Base case: only a single action.
 template <typename FinalAction>
 class [[nodiscard]] DoAllAction<FinalAction> {
  public:
   struct UserConstructorTag {};
 
   template <typename T>
   explicit DoAllAction(UserConstructorTag, T&& action)
       : final_action_(std::forward<T>(action)) {}
 
   // Rather than a call operator, we must define conversion operators to
   // particular action types. This is necessary for embedded actions like
   // DoDefault(), which rely on an action conversion operators rather than
   // providing a call operator because even with a particular set of arguments
   // they don't have a fixed return type.
 
   // We support conversion to OnceAction whenever the sub-action does.
   template <typename R, typename... Args,
             typename std::enable_if<
                 std::is_convertible<FinalAction, OnceAction<R(Args...)>>::value,
                 int>::type = 0>
   operator OnceAction<R(Args...)>() && {  // NOLINT
     return std::move(final_action_);
   }
 
   // We also support conversion to OnceAction whenever the sub-action supports
   // conversion to Action (since any Action can also be a OnceAction).
   template <
       typename R, typename... Args,
       typename std::enable_if<
           conjunction<
               negation<
                   std::is_convertible<FinalAction, OnceAction<R(Args...)>>>,
               std::is_convertible<FinalAction, Action<R(Args...)>>>::value,
           int>::type = 0>
   operator OnceAction<R(Args...)>() && {  // NOLINT
     return Action<R(Args...)>(std::move(final_action_));
   }
 
   // We support conversion to Action whenever the sub-action does.
   template <
       typename R, typename... Args,
       typename std::enable_if<
           std::is_convertible<const FinalAction&, Action<R(Args...)>>::value,
           int>::type = 0>
   operator Action<R(Args...)>() const {  // NOLINT
     return final_action_;
   }
 
  private:
   FinalAction final_action_;
 };
 
 // Recursive case: support N actions by calling the initial action and then
 // calling through to the base class containing N-1 actions.
 template <typename InitialAction, typename... OtherActions>
 class [[nodiscard]] DoAllAction<InitialAction, OtherActions...>
     : private DoAllAction<OtherActions...> {
  private:
   using Base = DoAllAction<OtherActions...>;
 
   // The type of reference that should be provided to an initial action for a
   // mocked function parameter of type T.
   //
   // There are two quirks here:
   //
   //  *  Unlike most forwarding functions, we pass scalars through by value.
   //     This isn't strictly necessary because an lvalue reference would work
   //     fine too and be consistent with other non-reference types, but it's
   //     perhaps less surprising.
   //
   //     For example if the mocked function has signature void(int), then it
   //     might seem surprising for the user's initial action to need to be
   //     convertible to Action<void(const int&)>. This is perhaps less
   //     surprising for a non-scalar type where there may be a performance
   //     impact, or it might even be impossible, to pass by value.
   //
   //  *  More surprisingly, `const T&` is often not a const reference type.
   //     By the reference collapsing rules in C++17 [dcl.ref]/6, if T refers to
   //     U& or U&& for some non-scalar type U, then InitialActionArgType<T> is
   //     U&. In other words, we may hand over a non-const reference.
   //
   //     So for example, given some non-scalar type Obj we have the following
   //     mappings:
   //
   //            T               InitialActionArgType<T>
   //         -------            -----------------------
   //         Obj                const Obj&
   //         Obj&               Obj&
   //         Obj&&              Obj&
   //         const Obj          const Obj&
   //         const Obj&         const Obj&
   //         const Obj&&        const Obj&
   //
   //     In other words, the initial actions get a mutable view of an non-scalar
   //     argument if and only if the mock function itself accepts a non-const
   //     reference type. They are never given an rvalue reference to an
   //     non-scalar type.
   //
   //     This situation makes sense if you imagine use with a matcher that is
   //     designed to write through a reference. For example, if the caller wants
   //     to fill in a reference argument and then return a canned value:
   //
   //         EXPECT_CALL(mock, Call)
   //             .WillOnce(DoAll(SetArgReferee<0>(17), Return(19)));
   //
   template <typename T>
   using InitialActionArgType =
       typename std::conditional<std::is_scalar<T>::value, T, const T&>::type;
 
  public:
   struct UserConstructorTag {};
 
   template <typename T, typename... U>
   explicit DoAllAction(UserConstructorTag, T&& initial_action,
                        U&&... other_actions)
       : Base({}, std::forward<U>(other_actions)...),
         initial_action_(std::forward<T>(initial_action)) {}
 
   // We support conversion to OnceAction whenever both the initial action and
   // the rest support conversion to OnceAction.
   template <
       typename R, typename... Args,
       typename std::enable_if<
           conjunction<std::is_convertible<
                           InitialAction,
                           OnceAction<void(InitialActionArgType<Args>...)>>,
                       std::is_convertible<Base, OnceAction<R(Args...)>>>::value,
           int>::type = 0>
   operator OnceAction<R(Args...)>() && {  // NOLINT
     // Return an action that first calls the initial action with arguments
     // filtered through InitialActionArgType, then forwards arguments directly
     // to the base class to deal with the remaining actions.
     struct OA {
       OnceAction<void(InitialActionArgType<Args>...)> initial_action;
       OnceAction<R(Args...)> remaining_actions;
 
       R operator()(Args... args) && {
         std::move(initial_action)
             .Call(static_cast<InitialActionArgType<Args>>(args)...);
 
         return std::move(remaining_actions).Call(std::forward<Args>(args)...);
       }
     };
 
     return OA{
         std::move(initial_action_),
         std::move(static_cast<Base&>(*this)),
     };
   }
 
   // We also support conversion to OnceAction whenever the initial action
   // supports conversion to Action (since any Action can also be a OnceAction).
   //
   // The remaining sub-actions must also be compatible, but we don't need to
   // special case them because the base class deals with them.
   template <
       typename R, typename... Args,
       typename std::enable_if<
           conjunction<
               negation<std::is_convertible<
                   InitialAction,
                   OnceAction<void(InitialActionArgType<Args>...)>>>,
               std::is_convertible<InitialAction,
                                   Action<void(InitialActionArgType<Args>...)>>,
               std::is_convertible<Base, OnceAction<R(Args...)>>>::value,
           int>::type = 0>
   operator OnceAction<R(Args...)>() && {  // NOLINT
     return DoAll(
         Action<void(InitialActionArgType<Args>...)>(std::move(initial_action_)),
         std::move(static_cast<Base&>(*this)));
   }
 
   // We support conversion to Action whenever both the initial action and the
   // rest support conversion to Action.
   template <
       typename R, typename... Args,
       typename std::enable_if<
           conjunction<
               std::is_convertible<const InitialAction&,
                                   Action<void(InitialActionArgType<Args>...)>>,
               std::is_convertible<const Base&, Action<R(Args...)>>>::value,
           int>::type = 0>
   operator Action<R(Args...)>() const {  // NOLINT
     // Return an action that first calls the initial action with arguments
     // filtered through InitialActionArgType, then forwards arguments directly
     // to the base class to deal with the remaining actions.
     struct OA {
       Action<void(InitialActionArgType<Args>...)> initial_action;
       Action<R(Args...)> remaining_actions;
 
       R operator()(Args... args) const {
         initial_action.Perform(std::forward_as_tuple(
             static_cast<InitialActionArgType<Args>>(args)...));
 
         return remaining_actions.Perform(
             std::forward_as_tuple(std::forward<Args>(args)...));
       }
     };
 
     return OA{
         initial_action_,
         static_cast<const Base&>(*this),
     };
   }
 
  private:
   InitialAction initial_action_;
 };
 
 template <typename T, typename... Params>
 struct ReturnNewAction {
   T* operator()() const {
     return internal::Apply(
         [](const Params&... unpacked_params) {
           return new T(unpacked_params...);
         },
         params);
   }
   std::tuple<Params...> params;
 };
 
 template <size_t k>
 struct ReturnArgAction {
   template <typename... Args,
             typename = typename std::enable_if<(k < sizeof...(Args))>::type>
   auto operator()(Args&&... args) const -> decltype(std::get<k>(
       std::forward_as_tuple(std::forward<Args>(args)...))) {
     return std::get<k>(std::forward_as_tuple(std::forward<Args>(args)...));
   }
 };
 
 template <size_t k, typename Ptr>
 struct SaveArgAction {
   Ptr pointer;
 
   template <typename... Args>
   void operator()(const Args&... args) const {
     *pointer = std::get<k>(std::tie(args...));
   }
 };
 
 template <size_t k, typename Ptr>
 struct SaveArgByMoveAction {
   Ptr pointer;
 
   template <typename... Args>
   void operator()(Args&&... args) const {
     *pointer = std::move(std::get<k>(std::tie(args...)));
   }
 };
 
 template <size_t k, typename Ptr>
 struct SaveArgPointeeAction {
   Ptr pointer;
 
   template <typename... Args>
   void operator()(const Args&... args) const {
     *pointer = *std::get<k>(std::tie(args...));
   }
 };
 
 template <size_t k, typename T>
 struct SetArgRefereeAction {
   T value;
 
   template <typename... Args>
   void operator()(Args&&... args) const {
     using argk_type =
         typename ::std::tuple_element<k, std::tuple<Args...>>::type;
     static_assert(std::is_lvalue_reference<argk_type>::value,
                   "Argument must be a reference type.");
     std::get<k>(std::tie(args...)) = value;
   }
 };
 
 template <size_t k, typename I1, typename I2>
 struct SetArrayArgumentAction {
   I1 first;
   I2 last;
 
   template <typename... Args>
   void operator()(const Args&... args) const {
     auto value = std::get<k>(std::tie(args...));
     for (auto it = first; it != last; ++it, (void)++value) {
       *value = *it;
     }
   }
 };
 
 template <size_t k>
 class [[nodiscard]] DeleteArgAction {
  public:
   template <typename... Args>
   void operator()(const Args&... args) const {
     DoDelete(std::get<k>(std::tie(args...)));
   }
 
  private:
   template <typename T>
   static void DoDelete(T* ptr) {
     delete ptr;
   }
 
   template <typename T>
   [[deprecated(
       "DeleteArg<N> used for a non-pointer argument, it was likely migrated "
       "to a smart pointer type. This action should be removed.")]]
   static void DoDelete(T&) {}
 };
 
 template <typename Ptr>
 struct ReturnPointeeAction {
   Ptr pointer;
   template <typename... Args>
   auto operator()(const Args&...) const -> decltype(*pointer) {
     return *pointer;
   }
 };
 
 #if GTEST_HAS_EXCEPTIONS
 template <typename T>
 struct ThrowAction {
   T exception;
   // We use a conversion operator to adapt to any return type.
   template <typename R, typename... Args>
   operator Action<R(Args...)>() const {  // NOLINT
     T copy = exception;
     return [copy](Args...) -> R { throw copy; };
   }
 };
 struct RethrowAction {
   std::exception_ptr exception;
   template <typename R, typename... Args>
   operator Action<R(Args...)>() const {  // NOLINT
     return [ex = exception](Args...) -> R { std::rethrow_exception(ex); };
   }
 };
 #endif  // GTEST_HAS_EXCEPTIONS
 
 }  // namespace internal
 
 // An Unused object can be implicitly constructed from ANY value.
 // This is handy when defining actions that ignore some or all of the
 // mock function arguments.  For example, given
 //
 //   MOCK_METHOD3(Foo, double(const string& label, double x, double y));
 //   MOCK_METHOD3(Bar, double(int index, double x, double y));
 //
 // instead of
 //
 //   double DistanceToOriginWithLabel(const string& label, double x, double y) {
 //     return sqrt(x*x + y*y);
 //   }
 //   double DistanceToOriginWithIndex(int index, double x, double y) {
 //     return sqrt(x*x + y*y);
 //   }
 //   ...
 //   EXPECT_CALL(mock, Foo("abc", _, _))
 //       .WillOnce(Invoke(DistanceToOriginWithLabel));
 //   EXPECT_CALL(mock, Bar(5, _, _))
 //       .WillOnce(Invoke(DistanceToOriginWithIndex));
 //
 // you could write
 //
 //   // We can declare any uninteresting argument as Unused.
 //   double DistanceToOrigin(Unused, double x, double y) {
 //     return sqrt(x*x + y*y);
 //   }
 //   ...
 //   EXPECT_CALL(mock, Foo("abc", _, _)).WillOnce(Invoke(DistanceToOrigin));
 //   EXPECT_CALL(mock, Bar(5, _, _)).WillOnce(Invoke(DistanceToOrigin));
 typedef internal::IgnoredValue Unused;
 
 // Deprecated single-argument DoAll.
 template <typename Action>
 GTEST_INTERNAL_DEPRECATE_AND_INLINE("Avoid using DoAll() for single actions")
 typename std::decay<Action>::type DoAll(Action&& action) {
   return std::forward<Action>(action);
 }
 
 // Creates an action that does actions a1, a2, ..., sequentially in
 // each invocation. All but the last action will have a readonly view of the
 // arguments.
 template <typename... Action>
 internal::DoAllAction<typename std::decay<Action>::type...> DoAll(
     Action&&... action) {
   return internal::DoAllAction<typename std::decay<Action>::type...>(
       {}, std::forward<Action>(action)...);
 }
 
 // WithArg<k>(an_action) creates an action that passes the k-th
 // (0-based) argument of the mock function to an_action and performs
 // it.  It adapts an action accepting one argument to one that accepts
 // multiple arguments.  For convenience, we also provide
 // WithArgs<k>(an_action) (defined below) as a synonym.
 template <size_t k, typename InnerAction>
 internal::WithArgsAction<typename std::decay<InnerAction>::type, k> WithArg(
     InnerAction&& action) {
   return {std::forward<InnerAction>(action)};
 }
 
 // WithArgs<N1, N2, ..., Nk>(an_action) creates an action that passes
 // the selected arguments of the mock function to an_action and
 // performs it.  It serves as an adaptor between actions with
 // different argument lists.
 template <size_t k, size_t... ks, typename InnerAction>
 internal::WithArgsAction<typename std::decay<InnerAction>::type, k, ks...>
 WithArgs(InnerAction&& action) {
   return {std::forward<InnerAction>(action)};
 }
 
 // WithoutArgs(inner_action) can be used in a mock function with a
 // non-empty argument list to perform inner_action, which takes no
 // argument.  In other words, it adapts an action accepting no
 // argument to one that accepts (and ignores) arguments.
 template <typename InnerAction>
 internal::WithArgsAction<typename std::decay<InnerAction>::type> WithoutArgs(
     InnerAction&& action) {
   return {std::forward<InnerAction>(action)};
 }
 
 // Creates an action that returns a value.
 //
 // The returned type can be used with a mock function returning a non-void,
 // non-reference type U as follows:
 //
 //  *  If R is convertible to U and U is move-constructible, then the action can
 //     be used with WillOnce.
 //
 //  *  If const R& is convertible to U and U is copy-constructible, then the
 //     action can be used with both WillOnce and WillRepeatedly.
 //
 // The mock expectation contains the R value from which the U return value is
 // constructed (a move/copy of the argument to Return). This means that the R
 // value will survive at least until the mock object's expectations are cleared
 // or the mock object is destroyed, meaning that U can safely be a
 // reference-like type such as std::string_view:
 //
 //     // The mock function returns a view of a copy of the string fed to
 //     // Return. The view is valid even after the action is performed.
 //     MockFunction<std::string_view()> mock;
 //     EXPECT_CALL(mock, Call).WillOnce(Return(std::string("taco")));
 //     const std::string_view result = mock.AsStdFunction()();
 //     EXPECT_EQ("taco", result);
 //
 template <typename R>
 internal::ReturnAction<R> Return(R value) {
   return internal::ReturnAction<R>(std::move(value));
 }
 
 // Creates an action that returns NULL.
 inline PolymorphicAction<internal::ReturnNullAction> ReturnNull() {
   return MakePolymorphicAction(internal::ReturnNullAction());
 }
 
 // Creates an action that returns from a void function.
 inline PolymorphicAction<internal::ReturnVoidAction> Return() {
   return MakePolymorphicAction(internal::ReturnVoidAction());
 }
 
 // Creates an action that returns the reference to a variable.
 template <typename R>
 inline internal::ReturnRefAction<R> ReturnRef(R& x) {  // NOLINT
   return internal::ReturnRefAction<R>(x);
 }
 
 // Prevent using ReturnRef on reference to temporary.
 template <typename R, R* = nullptr>
 internal::ReturnRefAction<R> ReturnRef(R&&) = delete;
 
 // Creates an action that returns the reference to a copy of the
 // argument.  The copy is created when the action is constructed and
 // lives as long as the action.
 template <typename R>
 inline internal::ReturnRefOfCopyAction<R> ReturnRefOfCopy(const R& x) {
   return internal::ReturnRefOfCopyAction<R>(x);
 }
 
 // DEPRECATED: use Return(x) directly with WillOnce.
 //
 // Modifies the parent action (a Return() action) to perform a move of the
 // argument instead of a copy.
 // Return(ByMove()) actions can only be executed once and will assert this
 // invariant.
 template <typename R>
 internal::ByMoveWrapper<R> ByMove(R x) {
   return internal::ByMoveWrapper<R>(std::move(x));
 }
 
 // Creates an action that returns an element of `vals`. Calling this action will
 // repeatedly return the next value from `vals` until it reaches the end and
 // will restart from the beginning.
 template <typename T>
 internal::ReturnRoundRobinAction<T> ReturnRoundRobin(std::vector<T> vals) {
   return internal::ReturnRoundRobinAction<T>(std::move(vals));
 }
 
 // Creates an action that returns an element of `vals`. Calling this action will
 // repeatedly return the next value from `vals` until it reaches the end and
 // will restart from the beginning.
 template <typename T>
 internal::ReturnRoundRobinAction<T> ReturnRoundRobin(
     std::initializer_list<T> vals) {
   return internal::ReturnRoundRobinAction<T>(std::vector<T>(vals));
 }
 
 // Creates an action that does the default action for the give mock function.
 inline internal::DoDefaultAction DoDefault() {
   return internal::DoDefaultAction();
 }
 
 // Creates an action that sets the variable pointed by the N-th
 // (0-based) function argument to 'value'.
 template <size_t N, typename T>
 internal::SetArgumentPointeeAction<N, T> SetArgPointee(T value) {
   return {std::move(value)};
 }
 
 // The following version is DEPRECATED.
 template <size_t N, typename T>
 internal::SetArgumentPointeeAction<N, T> SetArgumentPointee(T value) {
   return {std::move(value)};
 }
 
 // Creates an action that sets a pointer referent to a given value.
 template <typename T1, typename T2>
 PolymorphicAction<internal::AssignAction<T1, T2>> Assign(T1* ptr, T2 val) {
   return MakePolymorphicAction(internal::AssignAction<T1, T2>(ptr, val));
 }
 
 #ifndef GTEST_OS_WINDOWS_MOBILE
 
 // Creates an action that sets errno and returns the appropriate error.
 template <typename T>
 PolymorphicAction<internal::SetErrnoAndReturnAction<T>> SetErrnoAndReturn(
     int errval, T result) {
   return MakePolymorphicAction(
       internal::SetErrnoAndReturnAction<T>(errval, result));
 }
 
 #endif  // !GTEST_OS_WINDOWS_MOBILE
 
 // Various overloads for Invoke().
 
 // Legacy function.
 // This function exists for backwards compatibility.
 template <typename FunctionImpl>
 GTEST_INTERNAL_DEPRECATE_AND_INLINE(
     "Actions can now be implicitly constructed from callables. No need to "
     "create wrapper objects using Invoke().")
 typename std::decay<FunctionImpl>::type Invoke(FunctionImpl&& function_impl) {
   return std::forward<FunctionImpl>(function_impl);
 }
 
 // Creates an action that invokes the given method on the given object
 // with the mock function's arguments.
 template <class Class, typename MethodPtr>
 internal::InvokeMethodAction<Class, MethodPtr> Invoke(Class* obj_ptr,
                                                       MethodPtr method_ptr) {
   return {obj_ptr, method_ptr};
 }
 
 // Creates an action that invokes 'function_impl' with no argument.
 template <typename FunctionImpl>
 GTEST_INTERNAL_DEPRECATE_AND_INLINE(
     "Actions can now be implicitly constructed from zero-argument callables. "
     "No need to create wrapper objects using InvokeWithoutArgs().")
 std::decay_t<FunctionImpl> InvokeWithoutArgs(FunctionImpl&& function_impl) {
   return std::forward<FunctionImpl>(function_impl);
 }
 
 // Creates an action that invokes the given method on the given object
 // with no argument.
 template <class Class, typename MethodPtr>
 internal::InvokeMethodWithoutArgsAction<Class, MethodPtr> InvokeWithoutArgs(
     Class* obj_ptr, MethodPtr method_ptr) {
   return {obj_ptr, method_ptr};
 }
 
 // Creates an action that performs an_action and throws away its
 // result.  In other words, it changes the return type of an_action to
 // void.  an_action MUST NOT return void, or the code won't compile.
 template <typename A>
 inline internal::IgnoreResultAction<A> IgnoreResult(const A& an_action) {
   return internal::IgnoreResultAction<A>(an_action);
 }
 
 // Creates a reference wrapper for the given L-value.  If necessary,
 // you can explicitly specify the type of the reference.  For example,
 // suppose 'derived' is an object of type Derived, ByRef(derived)
 // would wrap a Derived&.  If you want to wrap a const Base& instead,
 // where Base is a base class of Derived, just write:
 //
 //   ByRef<const Base>(derived)
 //
 // N.B. ByRef is redundant with std::ref, std::cref and std::reference_wrapper.
 // However, it may still be used for consistency with ByMove().
 template <typename T>
 inline ::std::reference_wrapper<T> ByRef(T& l_value) {  // NOLINT
   return ::std::reference_wrapper<T>(l_value);
 }
 
 // The ReturnNew<T>(a1, a2, ..., a_k) action returns a pointer to a new
 // instance of type T, constructed on the heap with constructor arguments
 // a1, a2, ..., and a_k. The caller assumes ownership of the returned value.
 template <typename T, typename... Params>
 internal::ReturnNewAction<T, typename std::decay<Params>::type...> ReturnNew(
     Params&&... params) {
   return {std::forward_as_tuple(std::forward<Params>(params)...)};
 }
 
 // Action ReturnArg<k>() returns the k-th argument of the mock function.
 template <size_t k>
 internal::ReturnArgAction<k> ReturnArg() {
   return {};
 }
 
 // Action SaveArg<k>(pointer) saves the k-th (0-based) argument of the
 // mock function to *pointer.
 template <size_t k, typename Ptr>
 internal::SaveArgAction<k, Ptr> SaveArg(Ptr pointer) {
   return {pointer};
 }
 
 // Action SaveArgByMove<k>(pointer) moves the k-th (0-based) argument of the
 // mock function into *pointer.
 template <size_t k, typename Ptr>
 internal::SaveArgByMoveAction<k, Ptr> SaveArgByMove(Ptr pointer) {
   return {pointer};
 }
 
 // Action SaveArgPointee<k>(pointer) saves the value pointed to
 // by the k-th (0-based) argument of the mock function to *pointer.
 template <size_t k, typename Ptr>
 internal::SaveArgPointeeAction<k, Ptr> SaveArgPointee(Ptr pointer) {
   return {pointer};
 }
 
 // Action SetArgReferee<k>(value) assigns 'value' to the variable
 // referenced by the k-th (0-based) argument of the mock function.
 template <size_t k, typename T>
 internal::SetArgRefereeAction<k, typename std::decay<T>::type> SetArgReferee(
     T&& value) {
   return {std::forward<T>(value)};
 }
 
 // Action SetArrayArgument<k>(first, last) copies the elements in
 // source range [first, last) to the array pointed to by the k-th
 // (0-based) argument, which can be either a pointer or an
 // iterator. The action does not take ownership of the elements in the
 // source range.
 template <size_t k, typename I1, typename I2>
 internal::SetArrayArgumentAction<k, I1, I2> SetArrayArgument(I1 first,
                                                              I2 last) {
   return {first, last};
 }
 
 // Action DeleteArg<k>() deletes the k-th (0-based) argument of the mock
 // function.
 template <size_t k>
 internal::DeleteArgAction<k> DeleteArg() {
   return {};
 }
 
 // This action returns the value pointed to by 'pointer'.
 template <typename Ptr>
 internal::ReturnPointeeAction<Ptr> ReturnPointee(Ptr pointer) {
   return {pointer};
 }
 
 #if GTEST_HAS_EXCEPTIONS
 // Action Throw(exception) can be used in a mock function of any type
 // to throw the given exception.  Any copyable value can be thrown,
 // except for std::exception_ptr, which is likely a mistake if
 // thrown directly.
 template <typename T>
 typename std::enable_if<
     !std::is_base_of<std::exception_ptr, typename std::decay<T>::type>::value,
     internal::ThrowAction<typename std::decay<T>::type>>::type
 Throw(T&& exception) {
   return {std::forward<T>(exception)};
 }
 // Action Rethrow(exception_ptr) can be used in a mock function of any type
 // to rethrow any exception_ptr. Note that the same object is thrown each time.
 inline internal::RethrowAction Rethrow(std::exception_ptr exception) {
   return {std::move(exception)};
 }
 #endif  // GTEST_HAS_EXCEPTIONS
 
 namespace internal {
 
 // A macro from the ACTION* family (defined later in gmock-generated-actions.h)
 // defines an action that can be used in a mock function.  Typically,
 // these actions only care about a subset of the arguments of the mock
 // function.  For example, if such an action only uses the second
 // argument, it can be used in any mock function that takes >= 2
 // arguments where the type of the second argument is compatible.
 //
 // Therefore, the action implementation must be prepared to take more
 // arguments than it needs.  The ExcessiveArg type is used to
 // represent those excessive arguments.  In order to keep the compiler
 // error messages tractable, we define it in the testing namespace
 // instead of testing::internal.  However, this is an INTERNAL TYPE
 // and subject to change without notice, so a user MUST NOT USE THIS
 // TYPE DIRECTLY.
 struct ExcessiveArg {};
 
 // Builds an implementation of an Action<> for some particular signature, using
 // a class defined by an ACTION* macro.
 template <typename F, typename Impl>
 struct ActionImpl;
 
 template <typename Impl>
 struct ImplBase {
   struct Holder {
     // Allows each copy of the Action<> to get to the Impl.
     explicit operator const Impl&() const { return *ptr; }
     std::shared_ptr<Impl> ptr;
   };
   using type = typename std::conditional<std::is_constructible<Impl>::value,
                                          Impl, Holder>::type;
 };
 
 template <typename R, typename... Args, typename Impl>
 struct ActionImpl<R(Args...), Impl> : ImplBase<Impl>::type {
   using Base = typename ImplBase<Impl>::type;
   using function_type = R(Args...);
   using args_type = std::tuple<Args...>;
 
   ActionImpl() = default;  // Only defined if appropriate for Base.
   explicit ActionImpl(std::shared_ptr<Impl> impl) : Base{std::move(impl)} {}
 
   R operator()(Args&&... arg) const {
     static constexpr size_t kMaxArgs =
         sizeof...(Args) <= 10 ? sizeof...(Args) : 10;
     return Apply(std::make_index_sequence<kMaxArgs>{},
                  std::make_index_sequence<10 - kMaxArgs>{},
                  args_type{std::forward<Args>(arg)...});
   }
 
   template <std::size_t... arg_id, std::size_t... excess_id>
   R Apply(std::index_sequence<arg_id...>, std::index_sequence<excess_id...>,
           const args_type& args) const {
     // Impl need not be specific to the signature of action being implemented;
     // only the implementing function body needs to have all of the specific
     // types instantiated.  Up to 10 of the args that are provided by the
     // args_type get passed, followed by a dummy of unspecified type for the
     // remainder up to 10 explicit args.
     static constexpr ExcessiveArg kExcessArg{};
     return static_cast<const Impl&>(*this)
         .template gmock_PerformImpl<
             /*function_type=*/function_type, /*return_type=*/R,
             /*args_type=*/args_type,
             /*argN_type=*/
             typename std::tuple_element<arg_id, args_type>::type...>(
             /*args=*/args, std::get<arg_id>(args)...,
             ((void)excess_id, kExcessArg)...);
   }
 };
 
 // Stores a default-constructed Impl as part of the Action<>'s
 // std::function<>. The Impl should be trivial to copy.
 template <typename F, typename Impl>
 ::testing::Action<F> MakeAction() {
   return ::testing::Action<F>(ActionImpl<F, Impl>());
 }
 
 // Stores just the one given instance of Impl.
 template <typename F, typename Impl>
 ::testing::Action<F> MakeAction(std::shared_ptr<Impl> impl) {
   return ::testing::Action<F>(ActionImpl<F, Impl>(std::move(impl)));
 }
 
 #define GMOCK_INTERNAL_ARG_UNUSED(i, data, el) \
   , [[maybe_unused]] const arg##i##_type& arg##i
 #define GMOCK_ACTION_ARG_TYPES_AND_NAMES_UNUSED_          \
   [[maybe_unused]] const args_type& args GMOCK_PP_REPEAT( \
       GMOCK_INTERNAL_ARG_UNUSED, , 10)
 
 #define GMOCK_INTERNAL_ARG(i, data, el) , const arg##i##_type& arg##i
 #define GMOCK_ACTION_ARG_TYPES_AND_NAMES_ \
   const args_type& args GMOCK_PP_REPEAT(GMOCK_INTERNAL_ARG, , 10)
 
 #define GMOCK_INTERNAL_TEMPLATE_ARG(i, data, el) , typename arg##i##_type
 #define GMOCK_ACTION_TEMPLATE_ARGS_NAMES_ \
   GMOCK_PP_TAIL(GMOCK_PP_REPEAT(GMOCK_INTERNAL_TEMPLATE_ARG, , 10))
 
 #define GMOCK_INTERNAL_TYPENAME_PARAM(i, data, param) , typename param##_type
 #define GMOCK_ACTION_TYPENAME_PARAMS_(params) \
   GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_TYPENAME_PARAM, , params))
 
 #define GMOCK_INTERNAL_TYPE_PARAM(i, data, param) , param##_type
 #define GMOCK_ACTION_TYPE_PARAMS_(params) \
   GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_TYPE_PARAM, , params))
 
 #define GMOCK_INTERNAL_TYPE_GVALUE_PARAM(i, data, param) \
   , param##_type gmock_p##i
 #define GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params) \
   GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_TYPE_GVALUE_PARAM, , params))
 
 #define GMOCK_INTERNAL_GVALUE_PARAM(i, data, param) \
   , std::forward<param##_type>(gmock_p##i)
 #define GMOCK_ACTION_GVALUE_PARAMS_(params) \
   GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_GVALUE_PARAM, , params))
 
 #define GMOCK_INTERNAL_INIT_PARAM(i, data, param) \
   , param(::std::forward<param##_type>(gmock_p##i))
 #define GMOCK_ACTION_INIT_PARAMS_(params) \
   GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_INIT_PARAM, , params))
 
 #define GMOCK_INTERNAL_FIELD_PARAM(i, data, param) param##_type param;
 #define GMOCK_ACTION_FIELD_PARAMS_(params) \
   GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_FIELD_PARAM, , params)
 
 #define GMOCK_INTERNAL_ACTION(name, full_name, params)                         \
   template <GMOCK_ACTION_TYPENAME_PARAMS_(params)>                             \
   class full_name {                                                            \
    public:                                                                     \
     explicit full_name(GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params))               \
         : impl_(std::make_shared<gmock_Impl>(                                  \
               GMOCK_ACTION_GVALUE_PARAMS_(params))) {}                         \
     full_name(const full_name&) = default;                                     \
     full_name(full_name&&) noexcept = default;                                 \
     template <typename F>                                                      \
     operator ::testing::Action<F>() const {                                    \
       return ::testing::internal::MakeAction<F>(impl_);                        \
     }                                                                          \
                                                                                \
    private:                                                                    \
     class gmock_Impl {                                                         \
      public:                                                                   \
       explicit gmock_Impl(GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params))            \
           : GMOCK_ACTION_INIT_PARAMS_(params) {}                               \
       template <typename function_type, typename return_type,                  \
                 typename args_type, GMOCK_ACTION_TEMPLATE_ARGS_NAMES_>         \
       return_type gmock_PerformImpl(GMOCK_ACTION_ARG_TYPES_AND_NAMES_) const;  \
       GMOCK_ACTION_FIELD_PARAMS_(params)                                       \
     };                                                                         \
     std::shared_ptr<const gmock_Impl> impl_;                                   \
   };                                                                           \
   template <GMOCK_ACTION_TYPENAME_PARAMS_(params)>                             \
   [[nodiscard]] inline full_name<GMOCK_ACTION_TYPE_PARAMS_(params)> name(      \
       GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params));                               \
   template <GMOCK_ACTION_TYPENAME_PARAMS_(params)>                             \
   inline full_name<GMOCK_ACTION_TYPE_PARAMS_(params)> name(                    \
       GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params)) {                              \
     return full_name<GMOCK_ACTION_TYPE_PARAMS_(params)>(                       \
         GMOCK_ACTION_GVALUE_PARAMS_(params));                                  \
   }                                                                            \
   template <GMOCK_ACTION_TYPENAME_PARAMS_(params)>                             \
   template <typename function_type, typename return_type, typename args_type,  \
             GMOCK_ACTION_TEMPLATE_ARGS_NAMES_>                                 \
   return_type                                                                  \
   full_name<GMOCK_ACTION_TYPE_PARAMS_(params)>::gmock_Impl::gmock_PerformImpl( \
       GMOCK_ACTION_ARG_TYPES_AND_NAMES_UNUSED_) const
 
 }  // namespace internal
 
 // Similar to GMOCK_INTERNAL_ACTION, but no bound parameters are stored.
 #define ACTION(name)                                                          \
   class name##Action {                                                        \
    public:                                                                    \
     explicit name##Action() noexcept {}                                       \
     name##Action(const name##Action&) noexcept {}                             \
     template <typename F>                                                     \
     operator ::testing::Action<F>() const {                                   \
       return ::testing::internal::MakeAction<F, gmock_Impl>();                \
     }                                                                         \
                                                                               \
    private:                                                                   \
     class gmock_Impl {                                                        \
      public:                                                                  \
       template <typename function_type, typename return_type,                 \
                 typename args_type, GMOCK_ACTION_TEMPLATE_ARGS_NAMES_>        \
       return_type gmock_PerformImpl(GMOCK_ACTION_ARG_TYPES_AND_NAMES_) const; \
     };                                                                        \
   };                                                                          \
   [[nodiscard]] inline name##Action name();                                   \
   inline name##Action name() { return name##Action(); }                       \
   template <typename function_type, typename return_type, typename args_type, \
             GMOCK_ACTION_TEMPLATE_ARGS_NAMES_>                                \
   return_type name##Action::gmock_Impl::gmock_PerformImpl(                    \
       GMOCK_ACTION_ARG_TYPES_AND_NAMES_UNUSED_) const
 
 #define ACTION_P(name, ...) \
   GMOCK_INTERNAL_ACTION(name, name##ActionP, (__VA_ARGS__))
 
 #define ACTION_P2(name, ...) \
   GMOCK_INTERNAL_ACTION(name, name##ActionP2, (__VA_ARGS__))
 
 #define ACTION_P3(name, ...) \
   GMOCK_INTERNAL_ACTION(name, name##ActionP3, (__VA_ARGS__))
 
 #define ACTION_P4(name, ...) \
   GMOCK_INTERNAL_ACTION(name, name##ActionP4, (__VA_ARGS__))
 
 #define ACTION_P5(name, ...) \
   GMOCK_INTERNAL_ACTION(name, name##ActionP5, (__VA_ARGS__))
 
 #define ACTION_P6(name, ...) \
   GMOCK_INTERNAL_ACTION(name, name##ActionP6, (__VA_ARGS__))
 
 #define ACTION_P7(name, ...) \
   GMOCK_INTERNAL_ACTION(name, name##ActionP7, (__VA_ARGS__))
 
 #define ACTION_P8(name, ...) \
   GMOCK_INTERNAL_ACTION(name, name##ActionP8, (__VA_ARGS__))
 
 #define ACTION_P9(name, ...) \
   GMOCK_INTERNAL_ACTION(name, name##ActionP9, (__VA_ARGS__))
 
 #define ACTION_P10(name, ...) \
   GMOCK_INTERNAL_ACTION(name, name##ActionP10, (__VA_ARGS__))
 
 }  // namespace testing
 
 GTEST_DISABLE_MSC_WARNINGS_POP_()  // 4100
 
 #endif  // GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_

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