groovy.lang.DelegatingMetaClass not parameterized

Can you explain why this is a bug and what places you mean?

Because the method signatures use generic types without type parameters, i.e. raw types, any subclass has to use raw types in order to override methods. So for example:

public Object invokeMethod(Class sender, Object receiver, String methodName, Object[] arguments, boolean isCallToSuper, boolean fromInsideClass) {

The use of the raw type Class here disrupts subclassing for what is supposed to be a subclassed class. This is just one instance, there are many in this file.

with "disrupts" you mean the java compiler printing out a warning I guess. There are multiple uses of Class in this way in this class, yes. Besides Class I see no other. But I didn't look intensively. You want the above to change to something like:

public <T> Object invokeMethod(Class<T> sender, Object receiver, String methodName, Object[] arguments, boolean isCallToSuper, boolean fromInsideClass)

?