Query: Bind with members when type has cast to interface

[smitpatel]

Resolves #17276
Resolves #17099
Resolves #16759

Description

EF Core doesn't support mapping to interfaces directly. However, people frequently work with interfaces and we have provided guidance many times in the past on patterns that involve casting or using generic type constraints to work with interfaces. These patterns are not working in the new query pipeline like they were in the old, so we want to take a change for 3.0 that will allow these patterns to work again.

Example:

public static List<T> List<T>(this IQueryable<T> query) where T : IRemovable
    => query.Where(x => !x.IsRemoved).ToList();

Customer Impact

We expect that continuing to work with interfaces will be a common customer requirement for EF Core 3.0. We have not been able to come up with other workarounds that allow this.

Regression?

Yes, from 2.2.

Risk

The risk here is low because the code now handles interfaces types where it previously it would result in an exception. These changes are localized to specific places in the code and should have no impact on the handling of non-interface types.

[ajcvickers]

@smitpatel Approved by me, but wait for ask mode approval before merging.

[ajcvickers]

@smitpatel This is approved by Tactics; you may merge.