Implementando IList<T> em F#

Question

Procurei em todo o SO e na Internet, mas ainda não consigo descobrir o que estou perdendo e como implementar a interface IList genérica em F # para esse tipo:

type OrCondition() as self =
    inherit Condition()
    member val Conditions: List<Condition> = new List<Condition>() with get, set
    interface IList<Condition> with
        member this.Item 
            with get(index) = self.Conditions.[index]
            and  set(index)(value) = self.Conditions.[index] <- value
        member this.IndexOf item = self.Conditions.IndexOf(item)
        member this.Insert(index, item) = self.Conditions.Insert(index, item)
        member this.RemoveAt(index) = self.Conditions.RemoveAt(index)
        member this.Count with get() = self.Conditions.Count
        member this.IsReadOnly with get() = false
        member this.Add(item) = self.Conditions.Add(item)
        member this.Clear() = self.Conditions.Clear()
        member this.Contains(item) = self.Conditions.Contains(item)
        member this.CopyTo(conditions, index) = self.Conditions.CopyTo(conditions, index)
        member this.Remove(item) = self.Conditions.Remove(item)
        member this.GetEnumerator() = (Seq.cast<Condition> self.Conditions).GetEnumerator()

No momento, o compilador reclama que não implementei Collections.IEnumerable.GetEnumerator() e sei disso, mas realmente não sei como fazer isso.

Atualizar: Resultado final abaixo.Muito obrigado ao Sr.Festão.Além disso, vale ressaltar que mencionei apenas System.Collections.Generic e esqueci de referenciar System.Collection quando reside uma versão não genérica de IEnumerable.É triste que o ReSharper não suporte F#.

open System.Collections
open System.Collections.Generic

type OrCondition() as self =
    inherit Condition()
    member val Conditions = new List<Condition>() with get, set
    interface IList<Condition> with
        member this.Item 
            with get(index) = self.Conditions.[index]
            and  set(index)(value) = self.Conditions.[index] <- value
        member this.IndexOf item = self.Conditions.IndexOf(item)
        member this.Insert(index, item) = self.Conditions.Insert(index, item)
        member this.RemoveAt(index) = self.Conditions.RemoveAt(index)
        member this.Count with get() = self.Conditions.Count
        member this.IsReadOnly with get() = false
        member this.Add(item) = self.Conditions.Add(item)
        member this.Clear() = self.Conditions.Clear()
        member this.Contains(item) = self.Conditions.Contains(item)
        member this.CopyTo(conditions, index) = self.Conditions.CopyTo(conditions, index)
        member this.Remove(item) = self.Conditions.Remove(item)
        member this.GetEnumerator() = self.Conditions.GetEnumerator() :> IEnumerator<Condition>
        member this.GetEnumerator() = self.Conditions.GetEnumerator() :> IEnumerator 

Answer 1

Isto é porque IList tem dois GetEnumerator métodos, um para o IEnumerable<T> interface e um para o não genérico IEnumerable interface.

Você poderia adicionar este membro para implementar IEnumerable

member this.GetEnumerator() = (this.Conditions :> IEnumerable).GetEnumerator()

Answer 2

A maneira mais simples é

interface System.Collections.IEnumerable with
    member this.GetEnumerator() = this.Conditions.GetEnumerator() :> _