For all TypeScript functions, this could work somewhat reliably by checking the @developerPreview JSDoc tags, assuming that Angular consistently sets this JSDoc tag on their features which are in developer preview. This would work in a generic way. Though I can imagine this could be costly operations with performance implications.

However there might be functionality in developer preview which isn't used in TypeScript context, such as Control flow, experimental builders, experimental test runners, ... For this kind of functionality, IMHO it doesn't make sense to implement such a rule, as it needs to be implemented and kept up-to-date manually.

Would you be fine with a solution which exclusively works for TypeScript?

For all TypeScript functions, this could work somewhat reliably by checking the @developerPreview JSDoc tags, assuming that Angular consistently sets this JSDoc tag on their features which are in developer preview. This would work in a generic way. Though I can imagine this could be costly operations with performance implications.

However there might be functionality in developer preview which isn't used in TypeScript context, such as Control flow, experimental builders, experimental test runners, ... For this kind of functionality, IMHO it doesn't make sense to implement such a rule, as it needs to be implemented and kept up-to-date manually.

Would you be fine with a solution which exclusively works for TypeScript?

Exclusively Typescript would be better than nothing but there's a handful of new template features that are in preview,

It's a shame that it can't be a compiler option - angular/angular#57656