Tangential question:

Why do Haskell and Elm format lists like this?

    type alias Circle =
        { x : Float
        , y : Float
        , radius : Float
        }

...and not like this:

    type alias Circle = {
      x : Float,
      y : Float,
      radius : Float
    }

...? The first makes me shudder with revulsion every time I see it --- that's not where commas go, dammit --- and there must be a reason, which I've never been able to figure out.

The Elm style guide mentions in passing that trailing commas require a diff that adds a field to modify two lines but one, but that applies to leading commas too if you add the field at the beginning of the list.