F# type extension of generic type with concrete type parameter

Question

Is it possible to make a type extension for a generic type with a concrete type parameter? I failed with these syntaxes:

Syntax 1:

type Foo<Bar> with

    member this.BarStuff = // access `Bar´ specifics

Syntax 2:

type Foo<'T when 'T :> Bar> with

   member this.BarStuff = // access `Bar´ specifics

Answer 1

Yes, you can but you should use the C# style syntax:

open System.Runtime.CompilerServices

type Bar = Bar
type Foo<'t> = Foo of 't

[<Extension;Sealed>]
type Extensions =
    [<Extension>]
    static member BarStuff (this: Foo<Bar>) = ()


let x = (Foo Bar).BarStuff