Qml: Don't crash on bad grouped properties

Amend and cherry-pick e061c934d5a6d93493ba2be7b61efdd055d1e164.
This commit is required by the (already-merged)
commit dc69a005755c4d4c1b3de6cd52321b543b49a1a1 to successfully
fix the grouped property crash.

Add the reproducer of the issue in the tests.

Task-number: QTBUG-106457
Fixes: QTBUG-107795
Change-Id: I7da381d2c3b9c58d370c1ed754140637e065bdec
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

3 files changed, 43 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmllanguage/data/alias.15a.qml b/tests/auto/qml/qqmllanguage/data/alias.15a.qml
index ba8097c997..b5f96e15c1 100644
--- a/tests/auto/qml/qqmllanguage/data/alias.15a.qml
+++ b/tests/auto/qml/qqmllanguage/data/alias.15a.qml
@@ -9,4 +9,25 @@ Item {
     Item {
         id: symbol
     }
+
+    Rectangle {
+        id: txtElevationValue
+
+        property Rectangle background: Rectangle { }
+
+        state: "ValidatorInvalid"
+
+        states: [
+            State {
+                name: "ValidatorInvalid"
+                PropertyChanges {
+                    target: txtElevationValue
+                    background.border.color: "red" // this line caused the segfault in qtbug107795
+                }
+            },
+            State {
+                name: "ValidatorAcceptable"
+            }
+        ]
+    }
 }
diff --git a/tests/auto/qml/qqmllanguage/data/badGroupedProperty.qml b/tests/auto/qml/qqmllanguage/data/badGroupedProperty.qml
new file mode 100644
index 0000000000..34dcbf96fa
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/badGroupedProperty.qml
@@ -0,0 +1,10 @@
+import QtQml 2.15
+
+QtObject {
+    id: testItem
+    property rect rect
+    onComplete {
+        rect.x: 2
+        rect.width: 22
+    }
+}
diff --git a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
index 1be1533b63..ac6634290a 100644
--- a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
+++ b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
@@ -341,6 +341,7 @@ private slots:
     void ambiguousContainingType();
     void staticConstexprMembers();
     void bindingAliasToComponentUrl();
+    void badGroupedProperty();
 
 private:
     QQmlEngine engine;
@@ -5939,6 +5940,17 @@ void tst_qqmllanguage::bindingAliasToComponentUrl()
     }
 }
 
+void tst_qqmllanguage::badGroupedProperty()
+{
+    QQmlEngine engine;
+    const QUrl url = testFileUrl("badGroupedProperty.qml");
+    QQmlComponent c(&engine, url);
+    QVERIFY(c.isError());
+    QCOMPARE(c.errorString(),
+             QStringLiteral("%1:6 Cannot assign to non-existent property \"onComplete\"\n")
+             .arg(url.toString()));
+}
+
 QTEST_MAIN(tst_qqmllanguage)
 
 #include "tst_qqmllanguage.moc"