Which reminds me: I think we should allow calls to methods on `this` inside a constructor. (Do we?) A clean way to statically exclude incomplete values of `this` would be to outlaw such self-calls until all final fields are definitely assigned. The current language (for identity classes) computes this point (of complete field assignment) in order to enforce the rule that the constructor cannot return until all final fields have been definitely assigned.
FYI: A recent paper on the self-use-from-constructor problem: https://dl.acm.org/doi/10.1145/3428243
