The ways a shaped model still fails to be F#, repaired in place. FS0035: a generic abbreviation whose target leaves a parameter unused (`type Params<'P> = obj`) is rewritten as an erased phantom, which keeps the name and the arity; where the head itself is unwritable the declaration goes and its references widen. FS0033: a generic declaration named bare, and an application at an arity the head does not declare, widen to `obj`. FS0252: a settable property of type `unit` is demoted to read-only.