Idempotency problem: IndentSize = 2 broke offside rule

[nodakai]

Issue created from fantomas-online

Formatted code

This is already broken, see sharplab.io for my original code (which works as expected)

open System.IO

let f (x: StreamReader) =
  fun () ->
    match x.ReadLine() with
    | null -> None
    | ln -> Some(ln, ())
  |> Seq.unfold
  <| ()

for ln in f (File.OpenText @"\Windows\System32\Drivers\etc\hosts") do
  printfn $"%s{ln}"

Reformatted code

This clarifies how ^^^ was broken

open System.IO

let f (x: StreamReader) =
  fun () ->
    match x.ReadLine() with
    | null -> None
    | ln -> Some(ln, ())
    |> Seq.unfold
    <| ()

for ln in f (File.OpenText @"\Windows\System32\Drivers\etc\hosts") do
  printfn $"%s{ln}"

Problem description

Fantomas broke my code with IndentSize <= 3 where I suspect 3 came from "fun".Length

Extra information

• [x] The formatted result breaks my code.
• [ ] The formatted result gives compiler warnings.
• [x] I or my company would be willing to help fix this.

Options

Fantomas main branch at 2023-01-19T13:03:07Z - 813e63ab5c07fe5f5fd89328b9f5a7375ab43efb

    { config with
                IndentSize = 2 }

_{Did you know that you can ignore files when formatting from fantomas-tool or the FAKE targets by using a .fantomasignore file?}

[dawedawe]

Hey Kai, thanks for raising this issue. If you want to try fixing this issue by yourself, have a look at our documentation. Florians latest video is also a good resource.