type Hoge(id: int) =
    member internal this.id = id
    member x.Equals(y: Hoge) =
        x.id = y.id

let isEqual x y =
    x.Equals(y) // これは明らかに obj.Equals(obj)

let inline isEqual_< ^T when ^T : (member Equals : ^T -> bool) > x y =
    (^T : (member Equals : ^T -> bool) (x, y))

[<EntryPoint>]
let main args =
    let h1 = new Hoge(1)
    let h2 = new Hoge(1)
    printfn "%A" (isEqual_ h1 h2)
    0