qmllint: Support aliases to lists

Previously when resolving aliases all types of additional type information from the target was not copied over into the alias (writability, whether the property is a list etc.).
The alias should now accurately reflect the original property's type information.

Change-Id: I15078071716590f6a0e6262b8ad40ee946fe7da5
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

src/qmlcompiler/qqmljsimportvisitor.cpp

@@ -137,6 +137,7 @@ void QQmlJSImportVisitor::resolveAliases()
 
             QStringList components = property.typeName().split(u'.');
             QQmlJSScope::ConstPtr type;
+            QQmlJSMetaProperty targetProperty;
 
             // The first component has to be an ID. Find the object it refers to.
             const auto it = m_scopesById.find(components.takeFirst());
@@ -153,6 +154,7 @@ void QQmlJSImportVisitor::resolveAliases()
                     if (!target.type() && target.isAlias())
                         doRequeue = true;
                     type = target.type();
+                    targetProperty = target;
                 }
             }
 
@@ -163,6 +165,11 @@ void QQmlJSImportVisitor::resolveAliases()
                                         .arg(property.propertyName()), Log_Alias, object->sourceLocation());
             } else {
                 property.setType(type);
+                // Copy additional property information from target
+                property.setIsList(targetProperty.isList());
+                property.setIsWritable(targetProperty.isWritable());
+                property.setIsPointer(targetProperty.isPointer());
+
                 if (const QString internalName = type->internalName(); !internalName.isEmpty())
                     property.setTypeName(internalName);
             }

tests/auto/qml/qmllint/data/AliasListType.qml

@@ -0,0 +1,7 @@
+import QtQuick 2.15
+
+Item {
+    Item { id: item }
+
+    default property alias content: item.children
+}

tests/auto/qml/qmllint/data/aliasToList.qml

@@ -0,0 +1,6 @@
+import QtQuick 2.15
+
+AliasListType {
+        Item {}
+        Item {}
+}

tests/auto/qml/qmllint/tst_qmllint.cpp

@@ -748,6 +748,7 @@ void TestQmllint::cleanQmlCode_data()
     QTest::newRow("QtQuick.Window 2.1") << QStringLiteral("qtquickWindow21.qml");
     QTest::newRow("attachedTypeIndirect") << QStringLiteral("attachedTypeIndirect.qml");
     QTest::newRow("objectArray") << QStringLiteral("objectArray.qml");
+    QTest::newRow("aliasToList") << QStringLiteral("aliasToList.qml");
 }
 
 void TestQmllint::cleanQmlCode()