anchor.diff:  type IShapeFSharpOption =
       abstract Accept : IFSharpOptionVisitor<'R> -> 'R
   
  -type ShapeFSharpOption<'T> (unionCases : UnionCaseInfo list) =
  +type private ShapeFSharpOption<'T> (unionCases : UnionCaseInfo list) =
       inherit TypeShape<'T option> ()
       interface IShapeFSharpOption with
           member __.Accept v = v.Visit<'T> ()
  
positive.code: type IShapeFSharpList =
      abstract Accept : IFSharpListVisitor<'R> -> 'R
  
  type ShapeFSharpList<'T> (unionCases : UnionCaseInfo list) =
      inherit TypeShape<'T list> ()
      interface IShapeFSharpList with
          member __.Accept v = v.Visit<'T> ()
  
negative.code:     abstract Construct7 : 'Case7 -> 'Union
  
  
  type private ShapeFSharpUnion<'Union, 'Case1, 'Case2, 'Case3, 'Case4, 'Case5, 'Case6, 'Case7> (info : UnionInfo) =
      inherit TypeShape<'Union>()
      interface IShapeFSharpUnion<'Union, 'Case1, 'Case2, 'Case3, 'Case4, 'Case5, 'Case6, 'Case7> with
          member __.IsFSharpOption = false
  