Trying to use type checked closures in Groovy, including their parameters

groovy_closure_params_generics.groovy

private static File findOuputFile() {
  this.<File>logAndReturn('info', { File outputFile -> "Using '$outputFile' as output file" }) {
    new File("${System.getProperty('outputDir')}/memolo.html")
  }
}

private static <O> O logAndReturn(
  String logLevel,
  @ClosureParams(ThirdParam.FirstGenericType.class) Closure<String> stringMessageGenerator,
  Closure<O> resultProducer
) {
  O result = resultProducer()
  LoggerFactory.getLogger(this.class).invokeMethod(logLevel, stringMessageGenerator(result))
  result
}


// Compiler says: Expected parameter of type java.lang.Object but got java.io.File
// .<File>logAndReturn('info', { File outpu
//                               ^

As a test, I changed line 9 to have ThirdParam.class and, as expected, it said it was expecting a Closure but received a File.

But when I try with the generic, which is set to be File, it's says it expects an Object.

Code was tested against Groovy 2.3.2.

Currently the compiler looses the information about explicit type hints (.) so unfortunatly, this cannot work. We're aware of this: https://jira.codehaus.org/browse/GROOVY-6757

Feel free to comment on that issue with your example.