@clacke do you have an existence proof of FastSafeLang ⊆ SquishyLang?
I don't see how that works.
Seems to me that types and eg more control over memory requires more not less of a language, so (after seeing Mojo and reeading @mpweiher's blog) FastSafeLang ⊇ SquishyLang is possible, and seems natural.