protected function getResolvedValue(ResolvedParameterRegistry $resolvedParameters, O\Expression $expression)
 {
     foreach ($resolvedParameters->getParameters() as $parameter) {
         if ($parameter instanceof StructuralExpressionParameter && $parameter->getExpression() === $expression) {
             return $resolvedParameters->getValue($parameter);
         }
     }
     throw new PinqException('Could not get structural expression: matching expression was not found.');
 }