Brevity is the feature, not anonymity. What C# actually lacks is syntax sugar. But, a few years ago, I spent an hour or so implementing `Ad-hoc` classes for mos

Brevity is the feature, not anonymity. What C# actually lacks is syntax sugar. But, a few years ago, I spent an hour or so implementing `Ad-hoc` classes for most of the interfaces and abstract classes that I thought I would ever need, and it's been sufficient over 90% of the time[1]. N.b. these classes could have been generated programmatically. I'm not claiming that the technique is exactly equal to what Java gives you out of the box, but rather that C# can get within epsilon. In other words, for my purposes, the prefix AdHoc- might as well be a keyword (as in AdHocIEquality<T>, AdHocIEnumerable<T>†, AdHocDisposable, AdHocHttpHandler, etc...), because it's indistinguishable from syntax sugar. On the other hand, the F# object expression really is more than just syntax sugar, because of the way it interacts with type inference (no need to upcast to satisfy the type checker), and (as you noted) that it can implement an arbitrary set of interfaces. But, it's not all carrots and apples: F# lambdas don't work well with protected members. Meanwhile, C# can close over just about anything (a ref local, such as Span<T>, being the obvious exception). [1] https://github.com/noblethrasher/AdHoc-Implementations/blob/master/AdhocImplementations.cs https://github.com/noblethrasher/AdHoc-Implementations/blob/... (in a newer version, I implement the interfaces explicitly) † which, really only works well in VB because lambdas can contain `Yield` statements.