On an accessibility compilation error when a public type implements an internal interface in F# -

i wrote code like

type internal imyinterface =     abstract member method1 : unit -> unit  type class1() =       member this.y() =         (this :> imyinterface).method1()      interface imyinterface         member this.method1() = () 

note public type class1 implements internal interface imyinterface, compiles fine. in generated msil, "method1" shown private. similar explicit interfaces in c#.

however, when change code bit to

type internal foo() =     member x.value = "foo"  type internal imyinterface =     abstract member method1 : foo -> unit  type class1() =       member this.y() =         let v = foo()         (this :> imyinterface).method1(v)      interface imyinterface         member this.method1(v : foo) = () 

this type interface method "method1" takes internal type "foo" parameter. time, not compile error

the type 'foo' less accessible value, member or type 'override class1.method1 : v:foo -> unit' used in 

i have trouble decipher error message , find fix it. in c#, can write following code compiles fine

internal class foo {     string value { get; set; } }  internal interface imyinterface {     void method1(foo v); }  public class class1 : imyinterface {     public void y()     {         var v = new foo();         (this imyinterface).method1(v);     }      void imyinterface.method1(foo v)     {         throw new notimplementedexception();     } } 

any idea f# compiler error , how work around it?

btw: may not right way/pattern use interface anyway, i'm curious on language syntax

as pointed out @ patrick's comment, issue logged a bug of visual f#. it's included in f# 4.0 update 3 milestone.