Remove the preprocessor directives used to detect C++20

Author: YexuanXiao

strings/base_array.h

@@ -31,7 +31,6 @@ WINRT_EXPORT namespace winrt
             array_view(value.begin(), static_cast<size_type>(value.size()))
         {}
 
-#ifdef __cpp_lib_span
         template <typename C, std::size_t extent>
         array_view(std::span<C, extent> span) noexcept :
             array_view(span.data(), static_cast<size_type>(span.size())) 
@@ -43,7 +42,6 @@ WINRT_EXPORT namespace winrt
         {
             return { m_data, m_size };
         }
-#endif
 
         template <typename C, size_type N>
         array_view(C(&value)[N]) noexcept :
@@ -237,24 +235,22 @@ WINRT_EXPORT namespace winrt
     template <typename C, std::size_t N> array_view(std::array<C, N>& value) -> array_view<C>;
     template <typename C, std::size_t N> array_view(std::array<C, N> const& value) -> array_view<C const>;
 
-#ifdef __cpp_lib_span
     template <typename C, std::size_t extent> array_view(std::span<C, extent>& value) -> array_view<C>;
     template <typename C, std::size_t extent> array_view(std::span<C, extent> const& value) -> array_view<C const>;
-#endif
 
     template <typename T>
     struct com_array : array_view<T>
     {
-        using typename array_view<T>::value_type;
-        using typename array_view<T>::size_type;
-        using typename array_view<T>::reference;
-        using typename array_view<T>::const_reference;
-        using typename array_view<T>::pointer;
-        using typename array_view<T>::const_pointer;
-        using typename array_view<T>::iterator;
-        using typename array_view<T>::const_iterator;
-        using typename array_view<T>::reverse_iterator;
-        using typename array_view<T>::const_reverse_iterator;
+        using value_type = typename array_view<T>::value_type;
+        using size_type = typename array_view<T>::size_type;
+        using reference = typename array_view<T>::reference;
+        using const_reference = typename array_view<T>::const_reference;
+        using pointer = typename array_view<T>::pointer;
+        using const_pointer = typename array_view<T>::const_pointer;
+        using iterator = typename array_view<T>::iterator;
+        using const_iterator = typename array_view<T>::const_iterator;
+        using reverse_iterator = typename array_view<T>::reverse_iterator;
+        using const_reverse_iterator = typename array_view<T>::const_reverse_iterator;
 
         com_array(com_array const&) = delete;
         com_array& operator=(com_array const&) = delete;
@@ -293,14 +289,12 @@ WINRT_EXPORT namespace winrt
             com_array(value.begin(), value.end())
         {}
 
-#ifdef __cpp_lib_span
         template <typename U, std::size_t extent>
         explicit com_array(std::span<U, extent> span) noexcept : 
             com_array(span.data(), span.data() + span.size()) 
         {
             WINRT_ASSERT(span.size() <= (std::numeric_limits<size_type>::max)());
         }
-#endif
 
         template <typename U, std::size_t N>
         explicit com_array(U const(&value)[N]) :
@@ -403,9 +397,7 @@ WINRT_EXPORT namespace winrt
     template <std::size_t N, typename C> com_array(C const(&)[N]) -> com_array<std::decay_t<C>>;
     template <typename C> com_array(std::initializer_list<C>) -> com_array<std::decay_t<C>>;
 
-#ifdef __cpp_lib_span
     template <typename C, std::size_t extent> com_array(std::span<C, extent> const& value) -> com_array<std::decay_t<C>>;
-#endif
 
 
     namespace impl

strings/base_includes.h

@@ -25,10 +25,6 @@
 #include <utility>
 #include <vector>
 
-#if __has_include(<version>)
-#include <version>
-#endif
-
 // <windowsnumerics.impl.h> pulls in large, hard-to-control legacy headers. In header builds we keep the
 // existing behavior, but in module builds it's provided by the winrt.numerics module.
 #ifndef WINRT_MODULE
@@ -43,20 +39,10 @@
 #include <ostream>
 #endif
 
-#ifdef __cpp_lib_span
-#include <span>
-#endif
+// C++ 20 headers
 
-#ifdef __cpp_lib_format
+#include <version>
+#include <span>
 #include <format>
-#endif
-
-#ifdef __cpp_lib_source_location
 #include <source_location>
-#endif
-
-#ifdef __cpp_lib_coroutine
 #include <coroutine>
-#else
-#error C++/WinRT requires coroutine support, which is currently missing. Try enabling C++20 in your compiler.
-#endif

strings/base_string.h

@@ -327,7 +327,6 @@ WINRT_EXPORT namespace winrt
             return rend();
         }
 
-#ifdef __cpp_lib_starts_ends_with
         bool starts_with(wchar_t const value) const noexcept
         {
             return operator std::wstring_view().starts_with(value);
@@ -357,7 +356,6 @@ WINRT_EXPORT namespace winrt
         {
             return operator std::wstring_view().ends_with(pointer);
         }
-#endif
 
         bool empty() const noexcept
         {
@@ -437,10 +435,8 @@ WINRT_EXPORT namespace winrt
     }
 }
 
-#ifdef __cpp_lib_format
 template<>
 struct std::formatter<winrt::hstring, wchar_t> : std::formatter<std::wstring_view, wchar_t> {};
-#endif
 
 WINRT_EXPORT namespace winrt::impl
 {
@@ -574,7 +570,7 @@ WINRT_EXPORT namespace winrt::impl
         // when non-const (e.g. ranges::filter_view) so taking a const reference
         // as parameter wouldn't work for all scenarios.
         auto const size = std::formatted_size(args...);
-        WINRT_ASSERT(size < INT_MAX);
+        WINRT_ASSERT(size < static_cast<std::size_t>((std::numeric_limits<std::int32_t>::max)()));
         auto const size32 = static_cast<std::int32_t>(size);
 
         hstring_builder builder(size32);

strings/base_stringable_format.h

@@ -1,8 +1,6 @@
 
-#ifdef __cpp_lib_format
 template <typename FormatContext>
 auto std::formatter<winrt::Windows::Foundation::IStringable, wchar_t>::format(winrt::Windows::Foundation::IStringable const& obj, FormatContext& fc) const
 {
     return std::formatter<winrt::hstring, wchar_t>::format(obj.ToString(), fc);
 }
-#endif

strings/base_stringable_format_1.h

@@ -1,9 +1,7 @@
 
-#ifdef __cpp_lib_format
 template <>
 struct std::formatter<winrt::Windows::Foundation::IStringable, wchar_t> : std::formatter<winrt::hstring, wchar_t>
 {
     template <typename FormatContext>
     auto format(winrt::Windows::Foundation::IStringable const& obj, FormatContext& fc) const;
 };
-#endif