Comment gets duplicated

[knocte]

Issue created from fantomas-online

Code

type TorDirectory =
    private
        {
            NetworkStatus: NetworkStatusDocument
        }

    static member Bootstrap (nodeEndPoint: IPEndPoint) =
        async {
            return
                {
                    TorDirectory.NetworkStatus =
                        NetworkStatusDocument.Parse consensusStr
                    ServerDescriptors = Map.empty
                    // comment
                }
        }

Result

type TorDirectory =
    private
        { NetworkStatus: NetworkStatusDocument }

    static member Bootstrap(nodeEndPoint: IPEndPoint) =
        async {
            return
                { TorDirectory.NetworkStatus = NetworkStatusDocument.Parse consensusStr
                  ServerDescriptors = Map.empty
                // comment
                }
        // comment
        }

Extra information

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

Options

Fantomas 4.6 branch at 10/08/2021 09:24:03 - c12fa2d

Default Fantomas configuration

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

[nojaf]

Hey, thanks for reporting this issue.
The problem here is that we currently consider the entire range of the computation expression to look for a closing RBRACE token that might have trivia.

fantomas/src/Fantomas/CodePrinter.fs

Line 1445 in c97e732

+> enterNodeTokenByName synExpr.Range RBRACE

It will find the token from the record and think it is a match.
This can be resolved by limiting the range in which the token could possibly reside.
Something along the lines of

(fun ctx ->
                         let closingBraceRange =
                             ctx.MkRangeWith
                                 (synExpr.Range.EndLine, synExpr.Range.EndColumn - 1)
                                 (synExpr.Range.EndLine, synExpr.Range.EndColumn)

                         enterNodeTokenByName closingBraceRange RBRACE ctx)

Because of SynExpr.CompExpr has a range from the opening { to the closing one }.
Are you interested in submitting a PR?