EF Core features that require unsupported C# versions in LINQ expression trees

This is an issue to track EF Core feature which are blocked because of unsupported expression tree features. There's an ongoing effort to bring the latest C# features to expression trees, which would unblocked this. This list could be used to identify high-value features, in case prioritization is required on the Roslyn side.

* [ ] #26822
SQL row values (`(1, 'foo')`) could be represented by C# tuple literals; this could be great for e.g. expressing row value comparison (`WHERE (x, y) > (2, 3)`). The same would be needed for expressing subqueries returning multiple scalars in bulk update.
* [ ] If we could use assignment in expression trees, we could have a nice, terse method for expressing a single column update: `context.Customers.Where(...).Update(c => c.Age = c.Age + 1);`
* [ ] Another alternative is to use `with`: `context.Customers.Where(...).Update(c => c with { ... })`