Will work on a PR when got the time, just posting here for the record.

DynamicClassFactory.CreateType() will create a DynamicType with a "duplicate" constructor when the type has no properties and createParamterCtro = true.

This breaks later code when they try to find the constructor implementation.

I found this when doing:

                    var countQuery = query;

                    if (this.GroupBy != null)
                    {
                        countQuery = countQuery.GroupBy(
                            CustomParsingConfig.ParsingConfig,
                            this.GroupBy.KeySelector.Expression,
                            "new()");
                    }

                    result.Count = countQuery.Count();

Here I am using a dummy new() for the projection because I only want to count the results.

As a workaround, I replaced "new()" with "1", but still the bug is there.

The problem is when names.Length = 0:

The solution is to not create the second constructor if the type has no parameteres.