Repository navigation
Newline inconsistency in object expression #2990
Description
Activity
Hi there,
I believe it would be better if there was a new line between each member, this would make the code more consistent. I think that if all the member are single line then not having a new line is fine.
This is a topic for the style guide.
Also, the placement of the trailing } is not always placed on a new line.
In
helpers,}is placed on a new line because it had a blank line before it. That was preserved from the original code. This works as expected.In
helpers,}is placed on a new line because it had a blank line before it. That was preserved from the original code. This works as expected.You say that
}is placed on a new line because there is blank line before however the following snippet results in the same formatting:let helpers = { new IEncoderHelpers<JToken> with member _.encodeUInt32 value = JValue(box value) } let helpers2 = { new IEncoderHelpers<JToken> with member _.encodeUInt32 value = JValue(box value) }
Result
let helpers = { new IEncoderHelpers<JToken> with member _.encodeUInt32 value = JValue (box value) } let helpers2 = { new IEncoderHelpers<JToken> with member _.encodeUInt32 value = JValue (box value) }
In both cases the
}is pushed to a new line under the leading{.Options
[*.{fs,fsx}] max_line_length = 80 fsharp_space_before_uppercase_invocation = true fsharp_alternative_long_member_definitions = true fsharp_multi_line_lambda_closing_newline = true fsharp_bar_before_discriminated_union_declaration = true fsharp_multiline_bracket_style = stroustrup fsharp_keep_max_number_of_blank_lines = 2
Oh, I see. Your original report did not mention
fsharp_multiline_bracket_style = stroustrup.Stroustrup cannot be applied in absolutely every situation. I was convinced that
let x = { new System.IDisposable with member _.Dispose () = () }
was invalid code. (Producing an offset error).
In certain situations it can lead to invalid code.This does not seem the case.
I am pretty sure we decided against this for object expressions.
@josh-degraw does this ring a bell?So, we could double-check whether is indeed possible for object expressions.
If so, someone adds support for it. If not, we document that stroustrup cannot be used absolutely everywhere.Yeah that's sounds correct to me as far as what we did. However, wouldn't something like this be valid if we wanted to more strictly apply Stroustrup here?
let x = { new System.IDisposable with member _.Dispose () = () }
This would be how I would expect Stroustrup style to be applied here.
If it always leads to valid code, I'd be ok with this.
It really rings a bell that this wasn't the case.
Can't immediately find any prior art though.It is mentioned in the style guide. Guess this is possible.
Reacted by Josh DeGrawOh, I see. Your original report did not mention
fsharp_multiline_bracket_style = stroustrup.Ah yes sorry, I have a hard time finding which settings I have setup locally and not in the online tool.
🤖 This is an automated response from Repo Assist.
I tested the examples from this issue against the current
mainbranch withfsharp_multiline_bracket_style = stroustrup.Closing
}placement — the inconsistency reported here appears to be fixed. Bothhelpers(multiline body ending cleanly) andhelpers2(multiline body withuse/let-in tail) now consistently place}on its own line:let helpers2 = { new IDecoderHelpers with member _.anyToString jsonValue = if isNull jsonValue then "null" else use stream = new StringWriter(NewLine = "\n") stream.ToString() }
Blank lines between adjacent single-line members — as noted by
@nojafabove, the question of blank lines between interface members is a style-guide question. The current behaviour is:- A blank line is inserted before multiline member definitions (consistent with how Fantomas formats class member lists generally)
- Adjacent single-line members are not separated (no blank line between
asFloatandasInt)
This matches the Microsoft F# formatting guide for object expressions, which does not prescribe blank lines between single-line members.
If you are still seeing
}on the wrong line, or another inconsistency, with a current Fantomas version, please share a minimal repro and the Fantomas version number — I would be happy to investigate further. Otherwise this issue may be safe to close or moved todiscussionif you'd like to pursue the blank-line-between-all-members behaviour upstream.Generated by 🌈 Repo Assist at {run-started}. Learn more.
To install this agentic workflow, run
gh aw add githubnext/agentics/workflows/repo-assist.md@1f672aef974f4246124860fc532f82fe8a93a57e- added a commit that references this issue
on Sep 15, 2026 - added 2 commits that reference this issue
on Sep 21, 2026
Issue created from fantomas-online
Code
Result
Problem description
I believe it would be better if there was a new line between each member, this would make the code more consistent. I think that if all the member are single line then not having a new line is fine.
Also, the placement of the trailing
}is not always placed on a new line. I don't know what triggers that because in my project, I have a similar code as themember _.anyToString jsonValue =method and the}is placed on a new line and indented under the leading{.Extra information
Options
Fantomas main branch at 1/1/1990
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.