core/src/com/google/inject/internal/BytecodeGen.java
public static net.sf.cglib.reflect.FastClass newFastClassForMember(Member member) {
    return newFastClassForMember(member.getDeclaringClass(), member);
  }
public static net.sf.cglib.reflect.FastClass newFastClassForMember(Member member) {
    return newFastClassForMember(member.getDeclaringClass(), member);
  }
Returns a FastClass proxy for invoking the given member or {@code null} if access rules
disallow it.

@see #newFastClassForMember(Class, Member) for a full description