@maxd @finestructure Indeed, user-visible errors are frustrating to users! The question is whether static type checking meaningfully reduces user-visible errors in the same dev budget/timeframe, and empirical results on that are stubbornly inconclusive (and not for lack of research trying to get a solid answer!). The treadeoffs mostly remain exactly as you said in your post: an opinion. (I say this as a great fan of static types!)