[RFC] Mutable records as a GHC extension

It’s a well written proposal, and I’m interested in hearing from the experts who need all the mutability stuff purely as an interested bystander.

The stuff about g = f { x = a } , however, struck me as a non-sequitur. Sure, it has always been a pain to write for nested types, but the meaning has always been clear to me. “g equals f except/where x equals a”. I’m probably just missing something, but it seems unrelated to introducing mutable records. Your alternative says the same thing in more words and doesn’t seem any clearer. Can you clarify how it relates to the rest of the proposal?