Cannot use [MapDerivedType] with Map(IQueryable)

Describe the bug When using [MapDerivedType] and Map(IQuerable) in the same class, the generated code includes a switch statement in the Queryable.Select lambda

To Reproduce Steps to reproduce the behavior:

1. Declare a type Hierarchy with at least one base class and one derived class - let’s call them Parent and Child
2. Declare corresponding DTO types for those classes - ParentDto and ChildDto
3. Declare a static Mapper class and add a method with the following Signature : [MapDerivedType<Child, ChildDto>] public static partial ParentDto ToDto(Parent model);
4. Add the following method to the Mapper: public partial static IQueryable<ParentDto> ProjectToDto(this IQueryable<Parent> query);
5. The generated code will contain a switch statement in the generated lambda, which is not valid for Queryable expressions

Expected behavior The generated code should compile, and ideally map the hierachy correctly

Code snippets

public abstract class Parent {}
public class Child : Parent {}

public abstract class ParentDto {}
public class ChildDto: ParentDto {} //the inheritance here is unimportant, but is relevant for my use case

[Mapper]
public static partial class ParentChildMapper
{
    [MappDerivedType<Child, ChildDto>()]
    public static partial ParentDto ToDto(this Parent parent);

    public static partial IQuerable<ParentDto> ProjectToDto(this IQueryable<Parent> query);
}

Environment (please complete the following information):

• Mapperly Version: main branch (unreleased)
• .NET Version: 7.0.203
• Target Framework: .net7.0
• IDE: Rider 2023.1.1
• OS:

Additional context

I know this is pre-release, and I’m not using it in production, but it would be a nice use-case to be fulfilled.

[x2764tech]

@onionhammer It works - EF core will select the required columns and then do the “is” calculation client side. It may lead to over fetching, and maybe left joins (which might be avoided using subqueries with EF7)

[latonz]

This should now be fixed on main.