var result = postCollection
	.AsQueryable()
	.Select(p => new
	{
		Id = p.Id,
		Comments = p.Comments.ToList()
	})
	.ToList();

  Message: 
    System.NotSupportedException : The result operation MongoDB.Driver.Linq.Expressions.ResultOperators.ListResultOperator is not supported.
  Stack Trace: 
    AggregateLanguageTranslator.TranslatePipeline(PipelineExpression node)
    AggregateLanguageTranslator.TranslateValue(Expression node)
    AggregateLanguageTranslator.TranslateMapping(ProjectionMapping mapping)
    AggregateLanguageTranslator.TranslateNew(NewExpression node)
    AggregateLanguageTranslator.TranslateValue(Expression node)
    AggregateLanguageTranslator.Translate(Expression node, ExpressionTranslationOptions translationOptions)
    QueryableTranslator.TranslateProjectValue(Expression selector)
    QueryableTranslator.TranslateSelect(SelectExpression node)
    QueryableTranslator.Translate(Expression node)
    QueryableTranslator.TranslatePipeline(PipelineExpression node)
    QueryableTranslator.Translate(Expression node)
    QueryableTranslator.Translate(Expression node, IBsonSerializerRegistry serializerRegistry, ExpressionTranslationOptions translationOptions)
    MongoQueryProviderImpl`1.Translate(Expression expression)
    MongoQueryProviderImpl`1.Execute(Expression expression)
    MongoQueryableImpl`2.GetEnumerator()
    List`1.ctor(IEnumerable`1 collection)
    Enumerable.ToList[TSource](IEnumerable`1 source)