That's not necessarily connected to SE-0068, since the Self you want here is a dynamic self. @jckarter, do you think this would have to go through evolution?

IMO it fits with the decision notes of SE-0068, which specifically calls out that Self within the body of a class should refer to the dynamic type:

This proposal had light discussion in the community review process, but the core team heavily debated it. It includes two pieces:

1. Expanding the existing support for Self to work in value types, and in the bodies of classes.

2. Replacing the x.dynamicType expression with x.Self, a purely syntactic change that eliminates the “dynamicType” keyword.

The core team has accepted the first half for this proposal. This allows the use of “Self” as shorthand for referring to the containing type (in the case of structs, enums, and final class) or the dynamic type (in the case of non-final classes). Most of the discussion in the core team centered around whether people familiar with the former behavior would be surprised by the (more general) behavior when using it in a class, but they came to agree that this is actually a simple and general model, and a helpful point of consistency.

I agree with Hamish's sentiment. There's no obvious reason to me this shouldn't work, if we can make the compiler handle it correctly.

I have created a PR: #23430