anchor.diff:          | None -> Some(refName, IO.Path.Combine(paketDir, "packages", refName))
       else None
   
  +let rec tryFindPackageDllDir (targetFramework: TargetFramework) (dllDirs: string[]) =
  +    dllDirs |> Array.tryFind (fun dllDir ->
  +        dllDir.StartsWith(targetFramework.Framework) && dllDir <= targetFramework.Full)
  +    |> function
  +        | Some dllDir -> Some dllDir
  +        | None when targetFramework.Framework = "netcoreapp" ->
  +            if targetFramework.Version.StartsWith("1") then
  +                tryFindPackageDllDir { Framework = "netstandard"; Version = "1.6" } dllDirs
  +            elif targetFramework.Version.StartsWith("2") then
  +                tryFindPackageDllDir { Framework = "netstandard"; Version = "2.0" } dllDirs
  +            else None
  +        | None -> None
  +
   let tryGetPaketRef paketDir (targetFramework: TargetFramework) (refLine: string): PaketRef option =
       tryGetPaketRefNameAndDir paketDir (fun l -> l.StartsWith("Fable.") && not(l.StartsWith("Fable.Core"))) refLine
       |> Option.map (fun (refName, pkgDir) ->
  
positive.code: type TargetFramework =
      { Framework: string; Version: string }
      member this.Full = this.Framework + this.Version
  
  // PAKET -----------------------------------------------------
  [<RequireQualifiedAccess>]
  
negative.code: 
  let tryGetFableCoreJsDir projFile =
      let paketDir = tryFindPaketDirFromProject projFile
      let targetFramework = getTargetFramework None projFile
      tryGetFableCorePkgDir paketDir targetFramework projFile
      |> Option.map (fun corePkgDir -> IO.Path.Combine(corePkgDir, "fable-core"))
  
  // let checkFableCoreVersion paketDir projFile =
  