Mixed open and module (alias) statements introduce newlines

[deyanp]

Issue created from fantomas-online

Code

open System
open System.Threading
module IO = System.IO
open System.Regular
open System.Regular.Text

Result

open System
open System.Threading

module IO = System.IO

open System.Regular
open System.Regular.Text

Problem description

There should be no newline

Extra information

• [ ] The formatted result breaks my code.
• [ ] The formatted result gives compiler warnings.
• [ ] I or my company would be willing to help fix this.
• [ ] I would like a release if this problem is solved.

Options

Fantomas main branch at 2025-09-08T06:57:30Z - 31029b10ea2f2f0a8aa7a66c35264ede09cfb0b3

Default Fantomas configuration

_{Did you know that you can ignore files when formatting by using a .fantomasignore file? PS: It's unlikely that someone else will solve your specific issue, as it's something that you have a personal stake in.}

[nojaf]

This is only a problem from a certain point of view. What happens here makes sense to me according to Fantomas' internal rules. Open statements are grouped into an open list; module aliases are not part of that grouping. Thus we end up with three Oak nodes, two of which are multiline, which explains the newlines between the module aliases.