2 files changed, 73 insertions, 0 deletions
diff --git a/tests/auto/corelib/serialization/json/json.pro b/tests/auto/corelib/serialization/json/json.pro
index 8fa17c5c38..390a674f7a 100644
--- a/tests/auto/corelib/serialization/json/json.pro
+++ b/tests/auto/corelib/serialization/json/json.pro
@@ -1,6 +1,7 @@
 TARGET = tst_json
 QT = core-private testlib
 CONFIG += testcase
+contains(QT_CONFIG, c++2a):CONFIG *= c++2a
 
 !android:TESTDATA += bom.json test.json test.bjson test3.json test2.json
     else:RESOURCES += json.qrc
diff --git a/tests/auto/corelib/serialization/json/tst_qtjson.cpp b/tests/auto/corelib/serialization/json/tst_qtjson.cpp
index 3e58dd03cc..3f242ba2a0 100644
--- a/tests/auto/corelib/serialization/json/tst_qtjson.cpp
+++ b/tests/auto/corelib/serialization/json/tst_qtjson.cpp
@@ -68,6 +68,7 @@ private Q_SLOTS:
     void testObjectNestedEmpty();
 
     void testValueRef();
+    void testValueRefComparison();
     void testObjectIteration();
     void testArrayIteration();
 
@@ -176,6 +177,8 @@ private Q_SLOTS:
     void fromToVariantConversions_data();
     void fromToVariantConversions();
 
+    void noLeakOnNameClash();
+
 private:
     QString testDataDir;
 };
@@ -908,6 +911,57 @@ void tst_QtJson::testValueRef()
     QCOMPARE(object.value(QLatin1String("key")), QJsonValue(42));
 }
 
+void tst_QtJson::testValueRefComparison()
+{
+    QJsonValue a0 = 42.;
+    QJsonValue a1 = QStringLiteral("142");
+
+#define CHECK_IMPL(lhs, rhs, ineq) \
+    QCOMPARE(lhs, rhs); \
+    QVERIFY(!(lhs != rhs)); \
+    QVERIFY(lhs != ineq); \
+    QVERIFY(!(lhs == ineq)); \
+    QVERIFY(ineq != rhs); \
+    QVERIFY(!(ineq == rhs)); \
+    /* end */
+
+#define CHECK(lhs, rhs, ineq) \
+    do { \
+        CHECK_IMPL(lhs, rhs, ineq) \
+        CHECK_IMPL(qAsConst(lhs), rhs, ineq) \
+        CHECK_IMPL(lhs, qAsConst(rhs), ineq) \
+        CHECK_IMPL(qAsConst(lhs), qAsConst(rhs), ineq) \
+    } while (0)
+
+    // check that the (in)equality operators aren't ambiguous in C++20:
+    QJsonArray a = {a0, a1};
+
+    Q_STATIC_ASSERT((std::is_same<decltype(a[0]), QJsonValueRef>::value));
+
+    auto r0 = a.begin()[0];
+    auto r1 = a.begin()[1];
+    auto c0 = qAsConst(a).begin()[0];
+    // ref <> ref
+    CHECK(r0, r0, r1);
+    // cref <> ref
+    CHECK(c0, r0, r1);
+    // ref <> cref
+    CHECK(r0, c0, r1);
+    // ref <> val
+    CHECK(r0, a0, r1);
+    // cref <> val
+    CHECK(c0, a0, r1);
+    // val <> ref
+    CHECK(a0, r0, a1);
+    // val <> cref
+    CHECK(a0, c0, a1);
+    // val <> val
+    CHECK(a0, a0, a1);
+
+#undef CHECK
+#undef CHECK_IMPL
+}
+
 void tst_QtJson::testObjectIteration()
 {
     QJsonObject object;
@@ -3685,5 +3739,23 @@ void tst_QtJson::fromToVariantConversions()
     }
 }
 
+void tst_QtJson::noLeakOnNameClash()
+{
+    QJsonDocument doc = QJsonDocument::fromJson("{\"\":{\"\":0},\"\":0}");
+    QVERIFY(!doc.isNull());
+    const QJsonObject obj = doc.object();
+
+    // Removed the duplicate key.
+    QCOMPARE(obj.length(), 1);
+
+    // Retained the last of the duplicates.
+    const QJsonValue val = obj.begin().value();
+    QVERIFY(val.isDouble());
+    QCOMPARE(val.toDouble(), 0.0);
+
+    // It should not leak.
+    // In particular it should not forget to deref the container for the inner object.
+}
+
 QTEST_MAIN(tst_QtJson)
 #include "tst_qtjson.moc"