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  "path": "/t/rfc-mutable-records-as-a-ghc-extension/13886#post_6",
  "publishedAt": "2026-04-05T10:09:57.000Z",
  "site": "https://discourse.haskell.org",
  "textContent": "BurningWitness:\n\n> ADTs cannot be updated in place, they’re constructed anew each time, right? Why do we then use `x { a = b }` and not `C { a = b, .. = x }`?\n\nI agree with your distaste for that syntax. I especially dislike it’s called ‘update’ syntax, because there’s no update going on in the imperative programming sense of overwriting a location. ‘rebuild shorthand’ might be better terminology. I always use the explicit constructor syntax, which works reasonably smoothly with the `..` RecordWildcards.\n\nI agree the `HasField` and friends/‘update’ mechanisms are just too perplexing to be worth using. Indeed auto-naming a function same as a field (as in H98) runs counter to the drive to eliminate punning from other parts of the language.\n\nWhat’s more perspicuous in the earlier proposal’s `data` decl is that a mutable structure can appear only within `IO` (or `ST`).",
  "title": "[RFC] Mutable records as a GHC extension"
}