Crash when parsing constructor of inner classes with parameters annotated

public @interface A {}
public @interface B {}
public class Test {
    public class Inner {
	public Inner(@A Object a, @B Object b) {}
    }
}

		ClassParser cp = new ClassParser(args[0]);
		ClassGen cg = new ClassGen(cp.parse());
		MethodGen mg = new MethodGen(cg.getMethodAt(0), cg.getClassName(), cg.getConstantPool());
		mg.getAnnotationsOnParameter(0);