anchor.diff:  /// <seealso cref="Nonterminal{T}"/>
   type Nonterminal =
       inherit DesigntimeFarkle
  -    abstract Id: Guid
  +    /// The productions of the nonterminal.
       abstract Productions: Production list
   
   [<CompiledName("AbstractProduction")>]
   /// <summary>The base, untyped interface of <see cref="Production{T}"/>.</summary>
   /// <seealso cref="Production{T}"/>
   type Production =
  +    /// The members of the production.
       abstract Members: Symbol ImmutableArray
       abstract Fuse: obj [] -> obj
   
  
positive.code: /// <summary>The base, untyped class of the production builders.</summary>
  /// <remarks>
  ///     <para>A production builder is an object that helps to fluently construct <see cref="Production{T}"/>s
  ///     by aggregating the types of its significant parts. The types of the production's
  ///     significant parts are indicated by the type parameters. For example, a <c>ProductionBuilder</c> has no
  ///     significant parts, and a <c>ProductionBuilder&lt;int, string&gt;</c> has two significant parts; an integer
  ///     and a string.</para>
  ///     <para>Production builders have three basic methods.</para>
  ///     <para><c>Append</c> returns a production builder with the same significant parts,
  ///     but the given <see cref="DesigntimeFarkle"/> at the end of it.</para>
  ///     <para><c>Extend</c> returns a production builder with one more significant part,
  ///     whose type is determined by the given <see cref="DesigntimeFarkle{T}"/> that will
  ///     be appended to it.</para>
  ///     <para><c>Finish</c> accepts a function that converts all the builder's significant parts
  ///     into the eventual type of the returned <see cref="Production{T}"/>.</para>
  /// </remarks>
  /// <typeparam name="T">The type of the concrete production builder. Used so that
  
negative.code:     inherit DesigntimeFarkle
  
  /// <summary>A terminal symbol.</summary>
  /// <typeparam name="T">The type of the objects this terminal generates.</typeparam>
  type Terminal<'T> = internal {
      Id: Guid
      _Name: string
  