anchor.diff:      let tg = t.GetGenericArguments()
       if tg.Length <> 2 then raise DecoderException
       if i.FlattenCollections && tg.[0] = typeof<string> then
  -        callGeneric makeMap "makeMap" tg.[1] dD
  +        callGeneric <@ makeMap @> dD tg.[1]
       else
       let dK = dD tg.[0]
       let dV = dD tg.[1]
  
positive.code: 
  module IntelliFactory.WebSharper.Core.Json
  
  open System.Runtime.CompilerServices
  module A = IntelliFactory.WebSharper.Core.Attributes
  module P = IntelliFactory.JavaScript.Packager
  module R = IntelliFactory.WebSharper.Core.Reflection
  
negative.code:         t.IsGenericType &&
          t.GetGenericTypeDefinition() = typedefof<list<_>>
      then
          t.GetGenericArguments().[0]
          |> callGeneric <@ makeList @> dD
      else
      let cs =
          FST.GetUnionCases(t, flags)
  