Summary

When doing an aggregate containing a projection expression like:

.Project(
    augmentedProductType => new ProductTypeSearchResult
    {
        IsExternalUrl = string.IsNullOrEmpty(augmentedProductType.ShopUrl ?? "")
    }

 
An InvalidOperationException occurs with message "Cannot find serializer for null."

This happens with string.Empty as well.

Driver version 2.14.1

How to Reproduce

Steps to reproduce. If possible, please include a Short, Self Contained, Correct (Compilable), Example.

Additional Background

Please provide any additional background information that may be helpful in diagnosing the bug.

This seems to occur in ConstantExpressionToAggregationExpressionTranslator when making the call to get the serializer.