Annotation processor and anonymous classes

I'm trying to instrument some anonymous classes. For that I created an annotation:

@Target(ElementType.TYPE_USE)
@Retention(RetentionPolicy.SOURCE)
public @interface Ann {
}

An annotation processor:

@SupportedAnnotationTypes("Ann")
@SupportedSourceVersion(SourceVersion.RELEASE_11)
public class AP extends AbstractProcessor {
    @Override
    public boolean process(Set<? extends TypeElement> anns, RoundEnvironment env) {
        System.out.println("INVOKED");
        return true;
    }
}

I compiled these classes and created a test class:

public class T {
    interface I {
        void f();
    }

    public static void main(String[] args) {
        var o = new @Ann I() {
            @Override
            public void f() {
                System.out.println("f()");
            }
        };
    }
}

Then I tried compiling this class with the annotation processor:

javac src/test/java/T.java -cp build/classes/java/main/ -processor AP -d out

But it doesn't print anything. However, if I move the annotation @Ann from the anonymous class to the T class (@Ann public class T{), it works as expected.

How do I instrument anonymous classes using annotation processing?