anchor.diff:              makeRecord com ctx r isStruct values entRef genArgs
           | Fable.NewAnonymousRecord (values, fieldNames, genArgs, isStruct) -> makeTuple com ctx r isStruct values
           | Fable.NewUnion (values, tag, entRef, genArgs) ->
  -            let isStruct = (com.GetEntity entRef).IsValueType
  -            makeUnion com ctx r isStruct values tag entRef genArgs
  +            makeUnion com ctx r values tag entRef genArgs
   
       let calcVarAttrsAndOnlyRef com ctx (e: Fable.Expr) =
           let t = e.Type
  
positive.code:             if List.isEmpty values
              then callee
              else callFunction com ctx None callee values
          if isStruct || isCopyableEntity com Set.empty ent || ent.FullName = Types.result
          then expr
          else expr |> maybeWrapSmartPtr ent
  
  
negative.code:             else
                  fullName
  
      let makeUnion (com: IRustCompiler) ctx r values tag entRef genArgs =
          let ent = com.GetEntity(entRef)
          // let genArgs = transformGenArgs com ctx genArgs
          let unionCase = ent.UnionCases |> List.item tag
  