moc: Add support for C++17 nested namespaces (N4230)

[ChangeLog][moc] Added Support for C++17 nested namespaces

Change-Id: Ib83fc5bf48f66546fa97b49710582fbf9c984503
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

3 files changed, 86 insertions, 1 deletions

diff --git a/tests/auto/tools/moc/cxx17-namespaces.h b/tests/auto/tools/moc/cxx17-namespaces.h
new file mode 100644
index 0000000000..7c9f54d5f3
--- /dev/null
+++ b/tests/auto/tools/moc/cxx17-namespaces.h
@@ -0,0 +1,64 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Olivier Goffart.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** 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-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef CXX17_NAMESPACES_H
+#define CXX11_NAMESPACES_H
+#include <QtCore/QObject>
+
+#if defined(__cpp_nested_namespace_definitions) || defined(Q_MOC_RUN)
+namespace CXX17Namespace::A::B {
+namespace C::D {
+namespace E::F::G { } // don't confuse moc
+#else
+namespace CXX17Namespace { namespace A { namespace B {
+namespace C { namespace D {
+#endif
+
+Q_NAMESPACE
+
+class ClassInNamespace
+{
+    Q_GADGET
+public:
+    enum GadEn { Value = 3 };
+    Q_ENUM(GadEn)
+};
+
+enum NamEn { Value = 4 };
+Q_ENUM_NS(NamEn);
+
+
+#if defined(__cpp_nested_namespace_definitions) || defined(Q_MOC_RUN)
+}
+}
+#else
+} } }
+} }
+#endif
+
+#endif
diff --git a/tests/auto/tools/moc/moc.pro b/tests/auto/tools/moc/moc.pro
index d2b750bdc5..b7151f9c16 100644
--- a/tests/auto/tools/moc/moc.pro
+++ b/tests/auto/tools/moc/moc.pro
@@ -29,7 +29,7 @@ HEADERS += using-namespaces.h no-keywords.h task87883.h c-comments.h backslash-n
            non-gadget-parent-class.h grand-parent-gadget-class.h \
            related-metaobjects-in-gadget.h \
            related-metaobjects-name-conflict.h \
-           namespace.h
+           namespace.h cxx17-namespaces.h
 
 
 if(*-g++*|*-icc*|*-clang*|*-llvm):!irix-*:!win32-*: HEADERS += os9-newlines.h win-newlines.h
diff --git a/tests/auto/tools/moc/tst_moc.cpp b/tests/auto/tools/moc/tst_moc.cpp
index 98429a1f0d..2d7ec2f0b5 100644
--- a/tests/auto/tools/moc/tst_moc.cpp
+++ b/tests/auto/tools/moc/tst_moc.cpp
@@ -70,6 +70,7 @@
 #include "non-gadget-parent-class.h"
 #include "grand-parent-gadget-class.h"
 #include "namespace.h"
+#include "cxx17-namespaces.h"
 
 #ifdef Q_MOC_RUN
 // check that moc can parse these constructs, they are being used in Windows winsock2.h header
@@ -700,6 +701,7 @@ private slots:
     void optionsFileError_data();
     void optionsFileError();
     void testQNamespace();
+    void cxx17Namespaces();
 
 signals:
     void sigWithUnsignedArg(unsigned foo);
@@ -3803,6 +3805,25 @@ void tst_Moc::testQNamespace()
     QCOMPARE(FooNamespace::FooNestedNamespace::FooMoreNestedNamespace::staticMetaObject.enumeratorCount(), 1);
 }
 
+void tst_Moc::cxx17Namespaces()
+{
+    QCOMPARE(CXX17Namespace::A::B::C::D::staticMetaObject.className(),
+             "CXX17Namespace::A::B::C::D");
+    QCOMPARE(CXX17Namespace::A::B::C::D::staticMetaObject.enumeratorCount(), 1);
+    QCOMPARE(CXX17Namespace::A::B::C::D::staticMetaObject.enumerator(0).name(), "NamEn");
+    QCOMPARE(QMetaEnum::fromType<CXX17Namespace::A::B::C::D::NamEn>().name(), "NamEn");
+    QCOMPARE(QMetaEnum::fromType<CXX17Namespace::A::B::C::D::NamEn>().keyCount(), 1);
+    QCOMPARE(QMetaEnum::fromType<CXX17Namespace::A::B::C::D::NamEn>().value(0), 4);
+
+    QCOMPARE(CXX17Namespace::A::B::C::D::ClassInNamespace::staticMetaObject.className(),
+             "CXX17Namespace::A::B::C::D::ClassInNamespace");
+    QCOMPARE(CXX17Namespace::A::B::C::D::ClassInNamespace::staticMetaObject.enumeratorCount(), 1);
+    QCOMPARE(CXX17Namespace::A::B::C::D::ClassInNamespace::staticMetaObject.enumerator(0).name(), "GadEn");
+    QCOMPARE(QMetaEnum::fromType<CXX17Namespace::A::B::C::D::ClassInNamespace::GadEn>().name(), "GadEn");
+    QCOMPARE(QMetaEnum::fromType<CXX17Namespace::A::B::C::D::ClassInNamespace::GadEn>().keyCount(), 1);
+    QCOMPARE(QMetaEnum::fromType<CXX17Namespace::A::B::C::D::ClassInNamespace::GadEn>().value(0), 3);
+}
+
 QTEST_MAIN(tst_Moc)
 
 // the generated code must compile with QT_NO_KEYWORDS