Implicit mapping does not work in ProjectTo

[rmja]

Source/destination types

Failing test is here #3761

Mapping configuration

(see failing test)

Version: x.y.z

master

Expected behavior

It should be possible to use implicit/explicit mapping when using ProjectTo

Actual behavior

ProjectTo throws that no mapping is defined:

Steps to reproduce

See failing test pr. Make sure to remove the explicit mapping lines:

config.CreateMap<SourceValue, DestinationValue>().ConvertUsing(src => src);
config.CreateMap<SourceValue?, DestinationValue?>().ConvertUsing(src => src);

[lbargaoanu]

Custom conversion operators are for Map, not for ProjectTo. Try converting your test to an integration test.

[lbargaoanu]

Yes, because custom conversion operators are for Map, not for ProjectTo.

[rmja]

That is most likely correct, I do not have a deep understanding of AutoMapper, but my point is: Would it somehow be possible for ProjectTo to do "some kind of implicit conversion" when implicit operators exist for the type?

[lbargaoanu]

No, because that would be client evaluation, that's what Map does.

[rmja]

So what you are saying is that I am doing client evaluation when I do ProjectTo() with:

config.CreateMap<SourceValue, DestinationValue>().ConvertUsing(src => src);
config.CreateMap<SourceValue?, DestinationValue?>().ConvertUsing(src => src);

?

[lbargaoanu]

The custom operator is client evaluation. That other thing is some unnatural act :) Check the execution plan.