From da4820419e96d731a20166460ff444b7f02a8cc4 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Tue, 23 May 2023 15:44:20 +0200
Subject: [PATCH] Short live q20::type_identity

Trivial implementation. No test necessary.

Task-number: QTBUG-108124
Change-Id: I20ec14e49f4db6399502f953b569c889d30bb5a7
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit 62801532a33ab11d9bce42340c50619d49a7d0c8)
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
---
 src/corelib/global/q20type_traits.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/corelib/global/q20type_traits.h b/src/corelib/global/q20type_traits.h
index 2e812ed39c7..80ac1fa4313 100644
--- a/src/corelib/global/q20type_traits.h
+++ b/src/corelib/global/q20type_traits.h
@@ -38,6 +38,19 @@ using remove_cvref_t = std::remove_cv_t<std::remove_reference_t<T>>;
 #endif // __cpp_lib_remove_cvref
 }
 
+namespace q20 {
+// like std::type_identity(_t)
+#ifdef __cpp_lib_type_identity
+using std::type_identity;
+using std::type_identity_t;
+#else
+template <typename T>
+struct type_identity { using type = T; };
+template <typename T>
+using type_identity_t = typename type_identity<T>::type;
+#endif // __cpp_lib_type_identity
+}
+
 QT_END_NAMESPACE
 
 #endif /* Q20TYPE_TRAITS_H */