Option parameter name is lost in tuple

[nojaf]

Issue created from fantomas-online

Code

// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.

namespace Microsoft.FSharp.Control
    
    [<Sealed>]
    [<CompiledName("FSharpAsync")>]
    type Async =
        static member AwaitEvent: event:IEvent<'Del,'T> * ?cancelAction : (unit -> unit) -> Async<'T> when 'Del : delegate<'T,unit> and 'Del :> System.Delegate 

Result

// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.

namespace Microsoft.FSharp.Control

[<Sealed>]
[<CompiledName("FSharpAsync")>]
type Async =
    static member AwaitEvent: event: IEvent<'Del, 'T> * (unit -> unit) -> Async<'T>
        when 'Del: delegate<'T, unit> and 'Del :> System.Delegate

Problem description

cancelAction was lost after formatting.
This leads to a compiler bug in the original source at: https://github.com/dotnet/fsharp/blob/dab9d43fe3530f1df8de11fec4d5d278e8f3893e/src/fsharp/FSharp.Core/async.fsi#L360-L380

Extra information

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

Options

Fantomas master branch at 2022-03-11T12:09:54Z - b2d96b2

Default Fantomas configuration

Signature file

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