QmlJSEditor: Do not allow child items for states

Task-number: QTCREATORBUG-13003
Change-Id: I30bcee12803d2b3af804625ffdf417316e3d6c32
Reviewed-by: Tim Jenssen <tim.jenssen@theqtcompany.com>

src/libs/qmljs/qmljscheck.cpp

@@ -820,6 +820,9 @@ void Check::visitQmlObject(Node *ast, UiQualifiedId *typeId,
 
     const QString typeName = getRightMostIdentifier(typeId)->name.toString();
 
+    if (!m_typeStack.isEmpty() && m_typeStack.last() == QLatin1String("State"))
+        addMessage(StateCannotHaveChildItem, typeErrorLocation, typeName);
+
     if (checkTypeForDesignerSupport(typeId))
         addMessage(WarnUnsupportedTypeInVisualDesigner, typeErrorLocation, typeName);
 

src/libs/qmljs/qmljsstaticanalysismessage.cpp

@@ -235,6 +235,8 @@ StaticAnalysisMessages::StaticAnalysisMessages()
             tr("States are only supported in the root item in a Qt Quick UI form."));
     newMsg(ErrReferenceToParentItemNotSupportedInQmlUi, Error,
             tr("Referencing the parent of the root item is not supported in a Qt Quick UI form."));
+    newMsg(StateCannotHaveChildItem, Error,
+            tr("A State cannot have a child item (%1)."), 1);
 }
 
 } // anonymous namespace

src/libs/qmljs/qmljsstaticanalysismessage.h

@@ -88,6 +88,7 @@ enum Type
     HintExtraParentheses = 123,
     MaybeWarnEqualityTypeCoercion = 126,
     WarnConfusingExpressionStatement = 127,
+    StateCannotHaveChildItem = 128,
     HintDeclarationsShouldBeAtStartOfFunction = 201,
     HintOneStatementPerLine = 202,
     WarnImperativeCodeNotEditableInVisualDesigner = 203,