SpaceBeforeClassConstructor inserts two spaces before explicit Interface definition

[panmona]

Issue created from fantomas-online

Code

type IInterface =
    interface
    end

type IInterface2 =
    interface
        abstract member X: unit -> unit
    end

type IInterface3 =
   abstract member X: unit -> unit

Result

type IInterface  =
    interface
    end

type IInterface2  =
    interface
        abstract member X: unit -> unit
    end

type IInterface3 =
    abstract member X: unit -> unit

Problem description

With the setting space_before_class_constructor activated, Fantomas inserts two spaces between the end of interface name and the equal sign. This only happens when using the explicit interface keywords (interface and end) to define the interface.
When the lightweight syntax is used, this doesn't occur as can be seen in the IInterface3.

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 2022-05-04T06:20:06Z - 0e036ac

    { config with
                SpaceBeforeClassConstructor = 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.
I'm not really sure why this is happening.
If you want to take a stab at this, I would accept a PR to fix this.