In CSHARP-4220 we added support for the $documents stage using the aggregation builder APIs.

This ticket is about adding similar support in LINQ.

The syntax could look like this:

var result = database.AsQueryable()
    .Documents(documents)
    // more LINQ

Note that there currently is not an AsQueryable method on database (only on collection), so this would be a new method.

Also, the LINQ machinery currently assumes that all LINQ queries are against a collection, so before the LINQ version of Documents can be implemented the LINQ machinery will have to be refactored to allow queries against either a collection or a database.