When generating the method symbol for the anonymous inner class of the example:

    @Target(value = {ElementType.PARAMETER})
    @interface ParamAnnotation {}

    public class initParams {
        public initParams(@ParamAnnotation int i) {}

        public void m() {
            new initParams(2) {};
        }
    }

Javac will create an int parameter for it, named x0 instead of reusing the more logical "i" in this case.
Also the parameter annotation should be copied to the generated parameter.