Implement Values and Contains

Author: gusty

src/FSharpPlus/Extensions/Dict.fs

@@ -165,25 +165,41 @@ module Dict =
     /// <summary>Creates a conceptually infinite dictionay containing the same value for all possible keys.</summary>
     /// <param name="source">The value for all possible keys.</param>
     let initInfinite<'TKey,'TValue> (source: 'TValue) : IDictionary<'TKey,'TValue> =
-        { 
+
+        let icollection value =
+            {
+                new  ICollection<'t> with
+                    member __.Contains (item: 't) = obj.ReferenceEquals (item, value)
+                    member __.GetEnumerator () = (Seq.initInfinite (fun _ -> value)).GetEnumerator () :> System.Collections.IEnumerator
+                    member __.GetEnumerator () = (Seq.initInfinite (fun _ -> value)).GetEnumerator () : IEnumerator<'t>
+                    member __.IsReadOnly = true
+
+                    member __.Add (_item: 't) : unit                          = raise (System.NotImplementedException())
+                    member __.Clear () : unit                                 = raise (System.NotImplementedException())
+                    member __.CopyTo (_array: 't [], _arrayIndex: int) : unit = raise (System.NotImplementedException())
+                    member __.Count : int                                     = raise (System.NotImplementedException())
+                    member __.Remove (_item: 't): bool                        = raise (System.NotImplementedException())
+            }
+
+        {
             new IDictionary<'TKey,'TValue> with
                 member __.TryGetValue (_key: 'TKey, value: byref<'TValue>) = value <- source; true
                 member __.Count = System.Int32.MaxValue
                 member __.ContainsKey (_key: 'TKey) = true
+                member __.Contains (item: KeyValuePair<'TKey,'TValue>) = obj.ReferenceEquals (item.Value, source)
                 member __.GetEnumerator () = Seq.empty.GetEnumerator () :> System.Collections.IEnumerator
                 member __.GetEnumerator () = Seq.empty.GetEnumerator () : IEnumerator<KeyValuePair<'TKey,'TValue>>
                 member __.IsReadOnly = true
+                member __.Values = icollection source
                 member __.Item
                     with get (_key: 'TKey)   : 'TValue = source
                     and set  (_key: 'TKey) (_: 'TValue) : unit = raise (System.NotImplementedException())
 
                 member __.Add (_key: 'TKey, _value: 'TValue) : unit                              = raise (System.NotImplementedException())
                 member __.Add (_item: KeyValuePair<'TKey,'TValue>) : unit                        = raise (System.NotImplementedException())
                 member __.Clear () : unit                                                        = raise (System.NotImplementedException())
-                member __.Contains (_item: KeyValuePair<'TKey,'TValue>) : bool                   = raise (System.NotImplementedException())                
                 member __.CopyTo (_arr: KeyValuePair<'TKey,'TValue> [], _arrayIndex: int) : unit = raise (System.NotImplementedException())
                 member __.Keys : ICollection<'TKey>                                              = raise (System.NotImplementedException())
                 member __.Remove (_key: 'TKey) : bool                                            = raise (System.NotImplementedException())
                 member __.Remove (_item: KeyValuePair<'TKey,'TValue>) : bool                     = raise (System.NotImplementedException())
-                member __.Values : ICollection<'TValue>                                          = raise (System.NotImplementedException())
             }