Problem with model projection to DTO that inherits from another DTO.

[ghost]

Source/destination types

public sealed class Application
{
    public int Id { get; set; }
    public string Name { get; set; } = "";
    public int OwnerId { get; set; }
    public User Owner { get; set; } = null!;
    public ApplicationFlags Flags { get; set; }

    public long CreationTimestamp { get; set; }
    public long SecretKeyUpdateTimestamp { get; set; }
    public long LastUpdateTimestamp { get; set; }
    public long ClientId { get; set; }
    public byte[] SecretHash { get; set; } = Array.Empty<byte>();

    public ApiPermissions Permissions { get; set; }
    public ICollection<ApplicationRedirectUri> RedirectUris { get; set; } = null!;
}

public sealed class ApplicationRedirectUri
{
    public int Id { get; set; }
    public int ApplicationId { get; set; }
    public Application Application { get; set; } = null!;
    public string Uri { get; set; } = "";
}

public class ApplicationPartialOutputDto
{
    public int Id { get; set; }
    public string Name { get; set; } = "";
    public ApplicationFlags Flags { get; set; }
    public long ClientId { get; set; }
    public long CreationTimestamp { get; set; }
}

public class ApplicationDetailedOutputDto : ApplicationPartialOutputDto
{
    public long SecretKeyUpdateTimestamp { get; set; }
    public long LastUpdateTimestamp { get; set; }
    
    public ApiPermissions Permissions { get; set; }

    public List<string> RedirectUris { get; set; } = null!;
}

Mapping configuration

        CreateMap<Application, ApplicationPartialOutputDto>();

        CreateMap<Application, ApplicationDetailedOutputDto>();

        CreateMap<ApplicationRedirectUri, string>()
            .ConstructUsing(x => x.Uri);

Version: 11.0.1

I have AutoMapper.EF6 installed, I use EF6, and I use ProjectTo, from: namespace AutoMapper.QueryableExtensions.

Expected behavior

I expected that ApplicationDetailedOutputDto will be projected. Note: I wanted to make my life a little bit easier by making DetailedOutputDto a child of PartialOutputDto, and probably it's a source of all evil.

Actual behavior

      System.InvalidCastException: Unable to cast object of type 'System.Linq.Expressions.PropertyExpression' to type 'System.Linq.Expressions.NewExpression'.

Steps to reproduce

// My QOL extension method:
    public static IQueryable<T> ProjectToDto<T>(this IQueryable source)
    {
        return source.ProjectTo<T>(AutoMapperConfig.Configuration);
    }

// Test endpoint
        ApplicationPartialOutputDto? partialApp = _Ctx.Applications
            .ProjectToDto<ApplicationPartialOutputDto>()
            .FirstOrDefault(); // That doesn't throw
        
        ApplicationDetailedOutputDto? detailedApp = _Ctx.Applications
            .ProjectToDto<ApplicationDetailedOutputDto>()
            .FirstOrDefault(); // That throw

        return NoContent();

[lbargaoanu]

You need ConvertUsing instead of ConstructUsing.