How do you do .ThenInclude from F#?

[ctaggart]

After figuring out how to get the proxies to work in F# dotnet/efcore#12923, I tried to create queries using something like .Include(fun blog -> blog.Posts).ThenInclude(fun post -> post.Author), but post ends up being a collection. It fails in IntelliSense and during compilation. How do I make it work? Is there a workaround?

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• ID: bbd36f35-e257-d0ed-8f28-f539ddcb71ec
• Version Independent ID: 093903d5-f7c7-5a78-c0e5-0e2662dcedef
• Content: Loading Related Data - EF Core
• Content Source: entity-framework/core/querying/related-data.md
• Product: entity-framework
• GitHub Login: @rowanmiller
• Microsoft Alias: divega

[ajcvickers]

@ctaggart We can look into this, but two things I can mention off the top of my head:

• Visual Studio IntelliSense doesn't work for this in C#--see Completion missing members of lambda parameter in fault tolerance case roslyn#8237 (ReSharper/Ryder IntelliSense works fine for me.)
• You could try using string-based Include. That is, dot-separated navigation properties: .Include("Posts.Author")

[Ryan-Palmer]

I can confirm that the string version of Include is working in F#.

[dharmaturtle]

@manchoz's comment shows how to do it without hardcoding strings:

F# won't automatically upcast List<T> to IEnumerable<T>. Explicitly upcasting the .Include() lambda to IEnumberable<T> seems to resolve the issue:

let q =
    db.Schemas
       .Include(fun sch -> sch.Entities :> IEnumerable<_>)
           .ThenInclude(fun (ents : Entity) -> ents.Fields)
       .ToList()