generics handling incorrect, affects gpp

This is a distilled example of the problem:

import java.lang.ref.WeakReference
import java.util.concurrent.ConcurrentHashMap

@Typed class WeakValueMap<K2,V2> extends ConcurrentHashMap<K2,WeakValueMap.WV<V2>> {\n"+
  static class WV<VV> extends WeakReference<VV> {
  }
}

@Typed class Foo {
	private final WeakValueMap<String,Class> cache
	public x(String name) {
		def res = cache.get(name).get()
		foo(res)\n"+
	}
	public void foo(Class c) {
	}
}

If you compile that and use the groovy++ ast transform (I was on 0.4.170) it will give you an error that it can't find the method foo(Object) - the type of res has been incorrectly inferred. It should be Class but the representation of generics that groovy-eclipse builds is slightly different to that built by plain groovyc, and this causes the inferencing breakdown.