fun <T> checkForFailure(result: SyntacticResult<T>): CheckedResult<SyntacticResult<T>> =
        CheckedResult(collectingFailure(result))

    fun <T : LanguageTreeElement> checkForFailure(result: ElementResult<T>): CheckedResult<ElementResult<T>> =
        CheckedResult(collectingFailure(result))

    fun collectingFailure(maybeFailure: FailingResult?) {

            var isSelector = false
            var referenceSelector: CheckedResult<SyntacticResult<String>>? = null
            var referenceSourceData: SourceData? = null
            var functionCallSelector: CheckedResult<ElementResult<FunctionCall>>? = null
            var receiver: CheckedResult<ElementResult<Expr>>? = null // before dot
            children.forEach {