Caching compilation results errors

CompilationExample.scala

def compile(): List[CompiledScript] = {
  val outputCache = directory / ".cache"
  if(!outputCache.exists()) outputCache.mkdirs()

  val engine: IMain = new ScriptEngineManager().getEngineByName("scala").asInstanceOf[IMain]
  engine.settings.usejavacp.value = true
  // TODO: This breaks things. No idea why.
  // engine.settings.outdir.value = outputCache.getCanonicalPath

  directory.listFiles().toList collect {
    case file @ FileExtension("scala") => using(new FileReader(file))(engine.compile)
  }
}
  
/*

I get the following error when calling foreach eval() on the results:

[info] <console>:14: error: not found: value engine
[info]         }.asInstanceOf[Object]; def getEngine: javax.script.ScriptEngine = engine }

That source isn't in my own code.
*/