Super method calls from anonymous classes sometimes fail

class Foo {
  def foo(msg) {
  }
}

def z = new Foo() {

  def foo(Object msg) {
    return super.foo(msg);
  }

}

z.foo("42")

Caught: groovy.lang.MissingMethodException: No signature of method: test.foo() is applicable for argument types: (java.lang.String) values: [42]
Possible solutions: run(), run(), any(), any(groovy.lang.Closure), is(java.lang.Object), find(groovy.lang.Closure)
at test.this$dist$invoke$4(test.groovy)
at test$1.methodMissing(test.groovy)
at test$1.foo(test.groovy:9)
at test.run(test.groovy:14)