anchor.diff:  
           match resizeArray.FindIndex (System.Predicate predicate) with
           | -1 ->
  +            // TODO : Add a better error message.
  +            // keyNotFound ""
               raise <| System.Collections.Generic.KeyNotFoundException ()
           | index ->
               resizeArray.[index]
  
positive.code: 
          /// Removes the entry with the specified key from the Dictionary,
          /// returning a value indicating the success of the operation.
          let remove (k : 'Key) (d : IDictionary<'Key, 'T>) =
              if d.IsReadOnly then
                  invalidOp "Cannot remove an entry from a read-only dictionary."
              lock d <| fun () ->
                  d.Remove k
  
          /// Updates the value of an entry (which has the specified key)
          /// in the Dictionary, or creates a new entry if one doesn't exist.
          /// If the Dictionary is read-only, an InvalidOperationException is raised.
          let updateOrAdd k v (d : IDictionary<'Key, 'T>) =
              if d.IsReadOnly then
                  invalidOp "Cannot update or add an entry to a read-only dictionary."
              lock d <| fun () ->
                  d.[k] <- v
  
          /// Creates an immutable copy of a Dictionary.
          /// The entries are shallow-copied to the created Dictionary; that is,
          /// reference-typed keys and values will reference the same instances as
          /// in the mutable Dictionary, so care should be taken when using mutable keys and values.
          let toImmutable (d : IDictionary<'Key, 'T>) =
              lock d <| fun () ->
                  d
                  |> Seq.map (fun kvp ->
                      kvp.Key, kvp.Value)
                  |> dict
  
negative.code: [<RequireQualifiedAccess; CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
  module Seq =
      /// Returns the length of the sequence as an unsigned integer.
      let [<NoDynamicInvocation>] inline natLength (sequence : seq<'T>) =
          uint32 <| Seq.length sequence
  
      //
      let [<NoDynamicInvocation>] inline appendSingleton sequence (value : 'T) =
          Seq.append sequence (Seq.singleton value)
  
      //
      [<CompiledName("Project")>]
  