Reincarnated Bug (reminiscent of Issue 350) - ClassCastException with sophisticated generic class hierarchy

[hamid-nazari]

JMockit 1.10
TestNG 6.8.6.20141201_2240 (eclipse plug-in)
JDK 1.8

Some part of the the bug reported previously on Google's issue tracker, Issue 350, which was totally fixed by version 1.9, is back again in version 1.10. Specifically, the test case genericsFailure_ClassCast2, provided by the test suite attached to that reported issue, now fails again with the following error:

FAILED: genericsFailure_ClassCast2(tests.JMockitGenericsFailureTests$BackImpl@5ae63ade)

java.lang.IllegalArgumentException: tests.JMockitGenericsFailureTests$AppImpl is not an interface
    at java.lang.reflect.Proxy$ProxyClassFactory.apply(Proxy.java:590)
    at java.lang.reflect.Proxy$ProxyClassFactory.apply(Proxy.java:557)
    at java.lang.reflect.WeakCache$Factory.get(WeakCache.java:230)
    at java.lang.reflect.WeakCache.get(WeakCache.java:127)
    at java.lang.reflect.Proxy.getProxyClass0(Proxy.java:419)
    at java.lang.reflect.Proxy.newProxyInstance(Proxy.java:719)
    at tests.JMockitGenericsFailureTests$BackImpl.getApp(JMockitGenericsFailureTests.java)
    at tests.JMockitGenericsFailureTests$3.<init>(JMockitGenericsFailureTests.java:127)
    at tests.JMockitGenericsFailureTests.genericsFailure_ClassCast2(JMockitGenericsFailureTests.java:124)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:483)