1 files changed, 48 insertions, 21 deletions
diff --git a/src/corelib/global/qflags.h b/src/corelib/global/qflags.h
index 012cab2392..0fb0f8c6ae 100644
--- a/src/corelib/global/qflags.h
+++ b/src/corelib/global/qflags.h
@@ -1,12 +1,11 @@
 /****************************************************************************
 **
-** Copyright (C) 2021 The Qt Company Ltd.
+** Copyright (C) 2016 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
 **
-** $QT_BEGIN_LICENSE:COMM$
-**
+** $QT_BEGIN_LICENSE:LGPL$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
@@ -15,25 +14,26 @@
 ** and conditions see https://www.qt.io/terms-conditions. For further
 ** information use the contact form at https://www.qt.io/contact-us.
 **
-** $QT_END_LICENSE$
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
 **
+** $QT_END_LICENSE$
 **
 ****************************************************************************/
 
@@ -192,6 +192,33 @@ typedef uint Flags;
 
 #endif /* Q_NO_TYPESAFE_FLAGS */
 
+// restore bit-wise enum-enum operators deprecated in C++20,
+// but used in a few places in the API
+#if __cplusplus > 201702L // assume compilers don't warn if in C++17 mode
+  // in C++20 mode, provide user-defined operators to override the deprecated operations:
+# define Q_DECLARE_MIXED_ENUM_OPERATOR(op, Ret, LHS, RHS) \
+    constexpr inline Ret operator op (LHS lhs, RHS rhs) noexcept \
+    { return static_cast<Ret>(std::underlying_type_t<LHS>(lhs) op std::underlying_type_t<RHS>(rhs)); } \
+    /* end */
+#else
+  // in C++11-17 mode, statically-assert that this compiler's result of the
+  // operation is the same that the C++20 version would produce:
+# define Q_DECLARE_MIXED_ENUM_OPERATOR(op, Ret, LHS, RHS) \
+    Q_STATIC_ASSERT((std::is_same<decltype(std::declval<LHS>() op std::declval<RHS>()), Ret>::value));
+#endif
+
+#define Q_DECLARE_MIXED_ENUM_OPERATORS(Ret, Flags, Enum) \
+    Q_DECLARE_MIXED_ENUM_OPERATOR(|, Ret, Flags, Enum) \
+    Q_DECLARE_MIXED_ENUM_OPERATOR(&, Ret, Flags, Enum) \
+    Q_DECLARE_MIXED_ENUM_OPERATOR(^, Ret, Flags, Enum) \
+    /* end */
+
+#define Q_DECLARE_MIXED_ENUM_OPERATORS_SYMMETRIC(Ret, Flags, Enum) \
+    Q_DECLARE_MIXED_ENUM_OPERATORS(Ret, Flags, Enum) \
+    Q_DECLARE_MIXED_ENUM_OPERATORS(Ret, Enum, Flags) \
+    /* end */
+
+
 QT_END_NAMESPACE
 
 #endif // QFLAGS_H