Column Value Converters are not fired when using coalesce operator in a query

Good day, Recently I noticed a bug in either this library or in the Linq2Db query engine itself - I am not sure where exactly. The issue is that when defining a custom value converter in EF Core db context (for nullable DateTime in my particular case) they are not being fired when a query is using coalesce operator. However in pure EF Core they work just fine.

Here is a sample query:

          using var context = container.GetService<SampleDataContext>();
          var query = from t2 in context.TableTwo
                      join t1 in context.TableOne on t2.TableOneId equals t1.Id into t1j
                      from t1 in t1j.DefaultIfEmpty()
                      select new
                      {
                          t2.Code,
                          NullableDateColumn = t2.NullableDateColumn, //here the converter is launched properly
                          FromDate = t1.FromDate ?? t2.FromDate, //here the converter is not launched
                          ToDate = t1.ToDate ?? t2.ToDate, //here the converter is not launched
                      };

          var results = query.ToLinqToDB().ToList();

I have also attached a full sample project with two Nunit tests where the issue can be easily reproduced and they use the above query: Linq2DbDateConvertersBug.zip The test named TestEFCore passes however the test named TestLinq2Db fails - they both use the same logic and query so they should both pass.

I use Linq2Db together with EF Core in many projects and for me this synergy is just awesome, however because of this bug I recently have quite a lot of headaches. I noticed this for datetimes with relation to coalesce operator, however I think this bug can be affecting also other types of converters and operators as well.

[sdanyliv]

I have checked this particular case works.

[plukawski]

I have checked the newest release of Linq2Db 4.1.1 and I confirm all mentioned here issues are resolved. I am closing the issue as a result. Thanks for fixing this!