Agree with most of this, and even upvoted it, but... > I don’t feel like substructural types are really geared toward functional languages, however; where they

Agree with most of this, and even upvoted it, but... > I don’t feel like substructural types are really geared toward functional languages, however; where they really shine is safe imperative programming like Rust—for a particular definition of “safe”, anyway. I disagree with this. Even vanilla Standard ML and Haskell can benefit from substructural types. The structural rules (weakening, contraction) don't have to be an all-or-nothing proposition. Why should I be forced to pick one between garbage collection for in-memory data structures (which Rust won't give me, at least not out of the box), and deterministic reclamation guarantees for file handles and network connections (which ML and Haskell won't give me)? I want both!