Rename move_helper.hpp to ref_arg.hpp and use template alias

Shortens the call sites a lot: `typename ref_arg<Ts>::type` -> `ref_arg_t<Ts>`
MSVC 2017 seems to have issues with std::conditional_t so use the C++11
variant here.

include/turtle/constraints.hpp

@@ -11,7 +11,6 @@
 
 #include "config.hpp"
 #include "constraint.hpp"
-#include "detail/move_helper.hpp"
 #include "detail/void_t.hpp"
 #include "unwrap_reference.hpp"
 #include <boost/version.hpp>

include/turtle/detail/expectation.hpp

@@ -24,7 +24,7 @@ namespace mock { namespace detail {
     class default_matcher : public matcher_base<Args...>
     {
     private:
-        bool operator()(typename ref_arg<Args>::type...) override { return true; }
+        bool operator()(ref_arg_t<Args>...) override { return true; }
         void serialize(std::ostream& s) const override
         {
             constexpr auto arity = sizeof...(Args);
@@ -51,16 +51,16 @@ namespace mock { namespace detail {
 
     private:
         template<std::size_t... I>
-        bool is_valid_impl(std::index_sequence<I...>, typename ref_arg<Args>::type... t)
+        bool is_valid_impl(std::index_sequence<I...>, ref_arg_t<Args>... t)
         {
             using expander = bool[];
             bool result = true;
-            (void)expander{ result &= std::get<I>(matchers_)(std::forward<Args>(t))... };
+            (void)expander{ result &= std::get<I>(matchers_)(static_cast<ref_arg_t<Args>>(t))... };
             return result;
         }
-        bool operator()(typename ref_arg<Args>::type... t) override
+        bool operator()(ref_arg_t<Args>... t) override
         {
-            return is_valid_impl(std::make_index_sequence<sizeof...(Args)>{}, std::forward<Args>(t)...);
+            return is_valid_impl(std::make_index_sequence<sizeof...(Args)>{}, static_cast<ref_arg_t<Args>>(t)...);
         }
         template<std::size_t... I>
         void serialize_impl(std::index_sequence<I...>, std::ostream& s) const
@@ -87,7 +87,7 @@ namespace mock { namespace detail {
         multi_matcher(const F& f) : f_(f) {}
 
     private:
-        bool operator()(typename ref_arg<Args>::type... t) override { return f_(std::forward<Args>(t)...); }
+        bool operator()(ref_arg_t<Args>... t) override { return f_(static_cast<ref_arg_t<Args>>(t)...); }
         void serialize(std::ostream& s) const override { s << mock::format(f_); }
 
     private:
@@ -143,9 +143,9 @@ namespace mock { namespace detail {
 
         bool verify() const { return invocation_->verify(); }
 
-        bool is_valid(typename ref_arg<Args>::type... t) const
+        bool is_valid(ref_arg_t<Args>... t) const
         {
-            return !invocation_->exhausted() && (*matcher_)(std::forward<Args>(t)...);
+            return !invocation_->exhausted() && (*matcher_)(static_cast<ref_arg_t<Args>>(t)...);
         }
 
         bool invoke() const

include/turtle/detail/function.hpp

@@ -54,7 +54,7 @@ namespace mock { namespace detail {
         }
         expectation_type expect() { return impl_->expect(); }
 
-        R operator()(Ts... args) const { return (*impl_)(std::forward<Ts>(args)...); }
+        R operator()(Ts... args) const { return (*impl_)(static_cast<ref_arg_t<Ts>>(args)...); }
 
         friend std::ostream& operator<<(std::ostream& s, const function& f) { return s << *f.impl_; }
 

include/turtle/detail/function_impl.hpp

@@ -249,7 +249,7 @@ namespace mock { namespace detail {
             valid_ = false;
             for(const auto& expectation : expectations_)
             {
-                if(expectation.is_valid(std::forward<Args>(args)...))
+                if(expectation.is_valid(static_cast<ref_arg_t<Args>>(args)...))
                 {
                     if(!expectation.invoke())
                     {
@@ -266,7 +266,7 @@ namespace mock { namespace detail {
                     valid_ = true;
                     error_type::call(MOCK_FUNCTION_CONTEXT, expectation.file(), expectation.line());
                     if(expectation.functor())
-                        return expectation.functor()(std::forward<Args>(args)...);
+                        return expectation.functor()(static_cast<ref_arg_t<Args>>(args)...);
                     return expectation.trigger();
                 }
             }

include/turtle/detail/matcher_base.hpp

@@ -9,11 +9,11 @@
 #ifndef MOCK_MATCHER_BASE_HPP_INCLUDED
 #define MOCK_MATCHER_BASE_HPP_INCLUDED
 
-#include "move_helper.hpp"
+#include "ref_arg.hpp"
 #include <ostream>
 
 namespace mock { namespace detail {
-    template<typename... Ts>
+    template<typename... Args>
     class matcher_base
     {
     public:
@@ -22,7 +22,7 @@ namespace mock { namespace detail {
         matcher_base& operator=(const matcher_base&) = delete;
         virtual ~matcher_base() = default;
 
-        virtual bool operator()(typename ref_arg<Ts>::type...) = 0;
+        virtual bool operator()(ref_arg_t<Args>...) = 0;
 
         friend std::ostream& operator<<(std::ostream& s, const matcher_base& m)
         {

include/turtle/detail/move_helper.hpp

@@ -1,19 +0,0 @@
-// http://turtle.sourceforge.net
-//
-// Copyright Mathieu Champlon 2018
-//
-// Distributed under the Boost Software License, Version 1.0.
-// (See accompanying file LICENSE_1_0.txt or copy at
-// http://www.boost.org/LICENSE_1_0.txt)
-
-#ifndef MOCK_MOVE_HELPER_HPP_INCLUDED
-#define MOCK_MOVE_HELPER_HPP_INCLUDED
-
-#include <type_traits>
-
-namespace mock { namespace detail {
-    template<typename T>
-    using ref_arg = std::conditional<std::is_reference<T>::value, T, std::add_rvalue_reference_t<T>>;
-}} // namespace mock::detail
-
-#endif // MOCK_MOVE_HELPER_HPP_INCLUDED

include/turtle/detail/ref_arg.hpp

@@ -0,0 +1,22 @@
+// http://turtle.sourceforge.net
+//
+// Copyright Mathieu Champlon 2018
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef MOCK_REF_ARG_HPP_INCLUDED
+#define MOCK_REF_ARG_HPP_INCLUDED
+
+#include <type_traits>
+
+namespace mock { namespace detail {
+    /// Make T a reference type:
+    /// If T is already a reference type, return T, else return an rvalue reference to T
+    /// Useful to pass along arguments keeping the ability to modify them (e.g. move from them)
+    template<typename T>
+    using ref_arg_t = typename std::conditional<std::is_reference<T>::value, T, std::add_rvalue_reference_t<T>>::type;
+}} // namespace mock::detail
+
+#endif // MOCK_REF_ARG_HPP_INCLUDED

include/turtle/matcher.hpp

@@ -12,7 +12,7 @@
 #include "config.hpp"
 #include "constraints.hpp"
 #include "detail/is_functor.hpp"
-#include "detail/move_helper.hpp"
+#include "detail/ref_arg.hpp"
 #include "log.hpp"
 #include <cstring>
 #include <functional>
@@ -51,10 +51,7 @@ class matcher<Actual, mock::constraint<Constraint>>
 {
 public:
     explicit matcher(const constraint<Constraint>& c) : c_(c.c_) {}
-    bool operator()(typename detail::ref_arg<Actual>::type actual)
-    {
-        return c_(std::forward<typename detail::ref_arg<Actual>::type>(actual));
-    }
+    bool operator()(detail::ref_arg_t<Actual> actual) { return c_(static_cast<detail::ref_arg_t<Actual>>(actual)); }
     friend std::ostream& operator<<(std::ostream& s, const matcher& m) { return s << mock::format(m.c_); }
 
 private:
@@ -66,10 +63,7 @@ class matcher<Actual, Functor, std::enable_if_t<detail::is_functor<Functor, Actu
 {
 public:
     explicit matcher(const Functor& f) : c_(f) {}
-    bool operator()(typename detail::ref_arg<Actual>::type actual)
-    {
-        return c_(std::forward<typename detail::ref_arg<Actual>::type>(actual));
-    }
+    bool operator()(detail::ref_arg_t<Actual> actual) { return c_(static_cast<detail::ref_arg_t<Actual>>(actual)); }
     friend std::ostream& operator<<(std::ostream& s, const matcher& m) { return s << mock::format(m.c_); }
 
 private: