anchor.diff:  
   /// Identifies an instance member that defines
   /// a mutable value in a class instance, typically a field or property
  -and ShapeWriteMember<'DeclaringType, 'MemberType> private (label : string, memberInfo : MemberInfo, path : MemberInfo[]) =
  +and [<Sealed>] ShapeWriteMember<'DeclaringType, 'MemberType> private (label : string, memberInfo : MemberInfo, path : MemberInfo[]) =
       inherit ShapeMember<'DeclaringType, 'MemberType>(label, memberInfo, path)
   
   #if TYPESHAPE_EMIT
  
positive.code:     abstract Accept : IFSharpRecordVisitor<'R> -> 'R
  
  /// Identifies an F# record type
  and ShapeFSharpRecord<'Record> private () =
      let isStructRecord = typeof<'Record>.IsValueType
      let ctorInfo = FSharpValue.PreComputeRecordConstructorInfo(typeof<'Record>, allMembers)
      let props = FSharpType.GetRecordFields(typeof<'Record>, allMembers)
  
negative.code:     abstract Accept : IPocoVisitor<'R> -> 'R
  
  /// Denotes any .NET type that is either a class or a struct
  and [<Sealed>] ShapePoco<'Poco> private () =
      let isStruct = typeof<'Poco>.IsValueType
  
      let fields = 
  