Exception in multiple mockery instanciation of the same type

[karak]

Hi.

I'd like to try unit-testing with mocks in F# as well as other .NET languages,
and your library looks powerful and so cool.

But I came across a problem on an elementary program as following.

When I try to create 2 mock instances of the same type,
it throws System.ArgumentException with a message
such as "An item is already added that contains same key".

I'm sorry but the message is not accurate because it was translated to my mother language...

What shall I do to make multiple mockery-instanciation work?

Karak

-- code for reproduction
#light
module MultipleInstanciation

open NaturalSpec

type IFoo = interface
  end

let binaryFunc (foo1: IFoo) (foo2: IFoo) : unit = ()

type FooImpl = class
  new() = {}
    interface IFoo
  end

[<Scenario>]
let ``try to create 2 mock-instance``() =
  let foo1 = mock<IFoo> "mock1"
  let foo2 = mock<IFoo> "mock2" // throw Exception!
  //let foo2 = new FooImpl ()

  Given foo2
    |> When calculating binaryFunc foo1
    |> Verify

[karak]

Only to avoid this, I could use a specific interface by every scenario
that inherits the original interface(and I do).

However, I couldn't use this solution to ScenarioTemplate.
That's derange your useful feature and make it annoying.