Private record definition error with stroustrup style

[sheridanchris]

Issue created from fantomas-online

Code

type Person = private {
    FirstName: string
    LastName: string
}

Result

type Person = private
    {
        FirstName: string
        LastName: string
    }

Problem description

Formatting the above code with the below options results in a compiler error.
I expected the code to remain the same after format, which was not the case. Although, I may be mistaken on the expected output

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.

Options

Fantomas master branch at 2022-09-07T06:05:21Z - b0916a4

    { config with
                MultilineBlockBracketsOnSameColumn = true
                ExperimentalStroustrupStyle = true }

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

[nojaf]

Hello,

Thank you for reporting this issue.
This one is tricky, if you can fix this in an elegant way I guess we can store the original formatting.

What I mean by elegant is that the fix is a tweak in existing code, without having to rewrite everything we currently have. If that is not possible then we will have to fallback MultilineBlockBracketsOnSameColumn when the type has an access modifier.

Are you interested in submitting a PR for this?

[sheridanchris]

Hello,

Thank you for reporting this issue. This one is tricky, if you can fix this in an elegant way I guess we can store the original formatting.

What I mean by elegant is that the fix is a tweak in existing code, without having to rewrite everything we currently have. If that is not possible then we will have to fallback MultilineBlockBracketsOnSameColumn when the type has an access modifier.

Are you interested in submitting a PR for this?

I'm not familiar with the codebase, but I am interested in submitting a PR. I'll take a look and see if I can fix the issue.

[nojaf]

Great 😊, you can find some notes on the codebase over at https://fsprojects.github.io/fantomas/docs/contributors/Index.html.
Going through those pages should give you a general idea of how it works.

In practice you will most likely need to make a change around:

fantomas/src/Fantomas.Core/CodePrinter.fs

Lines 3413 to 3429 in 0981dfe

	and genMultilineSimpleRecordTypeDefnAlignBrackets astContext openingBrace withKeyword ms ao' fs closingBrace =
	// the typeName is already printed
	opt (indent +> sepNln) ao' genAccess
	+> enterNodeFor SynTypeDefnSimpleRepr_Record_OpeningBrace openingBrace
	+> sepOpenSFixed
	+> indentSepNlnUnindent (
	atCurrentColumn (
	leaveNodeFor SynTypeDefnSimpleRepr_Record_OpeningBrace openingBrace
	+> col sepNln fs (genField astContext "")
	)
	)
	+> sepNln
	+> genTriviaFor SynTypeDefnSimpleRepr_Record_ClosingBrace closingBrace sepCloseSFixed
	+> optSingle (fun _ -> unindent) ao'
	+> onlyIf (List.isNotEmpty ms) sepNln
	+> sepNlnBetweenTypeAndMembers withKeyword ms
	+> genMemberDefnList astContext ms

opt (indent +> sepNln) ao' genAccess will add the additional indent if the access modifier is present.
If ExperimentalStroustrupStyle is active you want to avoid this.

When submitting your PR you want to check https://github.com/fsprojects/fantomas/blob/master/CONTRIBUTING.md#pull-request-ground-rules first.

Don't hesitate to reach out if you have any questions.

[sheridanchris]

Is MultilineBlockBracketsOnSameColumnRecordTests.fs an appropriate place for tests? Does this warrant a new file?

[nojaf]

I would add the test in SynTypeDefnSimpleReprRecordTests.fs.