anchor.diff:      abstract Accept : IConstructorVisitor<'DeclaringType, 'R> -> 'R
   
   /// Identifies a constructor implementation shape
  -and ShapeConstructor<'DeclaringType, 'CtorArgs> private (ctorInfo : ConstructorInfo, arity : int) =
  +and [<Sealed>] ShapeConstructor<'DeclaringType, 'CtorArgs> private (ctorInfo : ConstructorInfo, arity : int) =
       let valueReader = 
           match arity with
           | 0 -> fun _ -> [||]
  
positive.code: 
  /// Denotes a type that behaves like a C# record:
  /// Carries a parameterless constructor and settable properties
  and ShapeCliMutable<'Record> private (defaultCtor : ConstructorInfo) =
      let properties =
          typeof<'Record>.GetProperties(allInstanceMembers)
          |> Seq.filter (fun p -> p.CanRead && p.CanWrite && p.GetIndexParameters().Length = 0)
  
negative.code:     abstract Visit : ShapeTuple<'Tuple> -> 'R 
  
  /// Identifies a specific System.Tuple shape
  and [<Sealed>] ShapeTuple<'Tuple> private () =
      let tupleInfo = mkTupleInfo typeof<'Tuple>
      let isStructTuple = typeof<'Tuple>.IsValueType
  
  