Proguard and interfaces with default method

I'm experiencing some problems during the proguard step of the build process.

The step stops with these errors:

com.google.android.gms.common.zza: can't find referenced class android.content.ServiceConnection$$CC
com.mypkg.misc.views.HintToast: can't find referenced class android.animation.Animator$AnimatorListener$$CC

Looking at the definition of these two classes:

public interface AnimatorListener {
    default void onAnimationStart(Animator animation, boolean isReverse) {
        throw new RuntimeException("Stub!");
    }

    default void onAnimationEnd(Animator animation, boolean isReverse) {
        throw new RuntimeException("Stub!");
    }

    void onAnimationStart(Animator var1);

    void onAnimationEnd(Animator var1);

    void onAnimationCancel(Animator var1);

    void onAnimationRepeat(Animator var1);
}

and

public interface ServiceConnection {
    void onServiceConnected(ComponentName var1, IBinder var2);

    void onServiceDisconnected(ComponentName var1);

    default void onBindingDied(ComponentName name) {
        throw new RuntimeException("Stub!");
    }
}

seems that my Proguard configuration file isn't properly handling default methods of interfaces.