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Can't access an interface member via an implementing class
f#

Hi,

I'm failing to understand why the member "test" below cannot see the member "bah" implemented in the same class (in order to meet the contract for interface I).

I must be missing something very basic here. Could someone please put me out of my misery.

many thanks,

Roly

open System

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    type I =

        abstract bah : int

    type X = 

        class

            interface I with

                member x.bah = 5

            member x.test : int = x.bah // error

        end
.

All F# interfaces are implemented explicitly, which means you must upcast to the interface type to call the method:

member x.test : int = (x :> I).bah // ok

This is like in C# if you implement the interface with "I.bah" rather than just "bah".

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    interface I
    {
        int bah();
    }
    class X : I
    {
        int I.bah() { return 42; }
        //public int test() { return this.bah(); } // error
        public int test() { return ((I)this).bah(); } // ok
    }
By on 8/10/2009 3:57 PM ()

Many thanks!

By on 8/12/2009 5:40 AM ()

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