qmllint: Consider attached properties

We cannot figure out who attached properties to what, therefore we
consider any uppercase property we cannot locate as a potential attached
property.

Change-Id: I60508b9e4e038a51b87c56edf0796ac492aa3fa0
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

tests/auto/qml/qmllint/data/AttachedProps.qml

@@ -0,0 +1,6 @@
+import QtQml 2.0
+
+QtObject {
+    id: self
+    property var foo: self.Component.completed
+}

tests/auto/qml/qmllint/tst_qmllint.cpp

@@ -191,6 +191,7 @@ void TestQmllint::cleanQmlCode_data()
     QTest::newRow("goodAlias")                 << QStringLiteral("goodAlias.qml");
     QTest::newRow("goodParent")                << QStringLiteral("goodParent.qml");
     QTest::newRow("goodTypeAssertion")         << QStringLiteral("goodTypeAssertion.qml");
+    QTest::newRow("AttachedProps")             << QStringLiteral("AttachedProps.qml");
 }
 
 void TestQmllint::cleanQmlCode()

tools/qmllint/scopetree.cpp

@@ -230,6 +230,16 @@ bool ScopeTree::checkMemberAccess(
         type = types.value(type->superclassName());
     }
 
+    if (access->m_name.front().isUpper() && scope->scopeType() == ScopeType::QMLScope) {
+        // may be an attached type
+        const auto it = types.find(access->m_name);
+        if (it != types.end() && !(*it)->attachedTypeName().isEmpty()) {
+            const auto attached = types.find((*it)->attachedTypeName());
+            if (attached != types.end())
+                return checkMemberAccess(code, access.get(), attached->get(), types, colorOut);
+        }
+    }
+
     colorOut.write("Warning: ", Warning);
     colorOut.write(QString::fromLatin1(
                            "Property \"%1\" not found on type \"%2\" at %3:%4\n")