VerifyError - Expecting to find integer on stack

The line
result = prime * result + (int) (_tagReservationDate ^ (_tagReservationDate >>> 32))
produces bytecode that fails to run in the accompanying test.

<error message="(class: com/peersaver/model/Breaking, method: hashCode signature: ()I) Expecting to find integer on stack" type="java.lang.VerifyError">java.lang.VerifyError: (class: com/peersaver/model/Breaking, method: hashCode signature: ()I) Expecting to find integer on stack
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at com.peersaver.model.BreakingTest.class$(BreakingTest.groovy)
at com.peersaver.model.BreakingTest.$get$$class$com$peersaver$model$Breaking(BreakingTest.groovy)
at com.peersaver.model.BreakingTest.testBreaking(BreakingTest.groovy:55)
</error>

The email conversation that covers drilling down into details can be found here:
http://groovy.329449.n5.nabble.com/VerifyError-when-upgrading-from-Groovy-1-7-6-to-1-8-1-td4632721.html

The relevant bit, quoting BlackDragon:
"
> L13
> ILOAD 3: prime
> [int] ILOAD 5: result
> [int,int] IMUL
> [int] ALOAD 0: this
> [int, this] GETFIELD TrackingTagReservation._tagReservationDate : long
> [int, long] ALOAD 0: this
> [int, long, this] GETFIELD TrackingTagReservation._tagReservationDate : long
> [int, long, long] LDC 32
> [int, long, long, int] I2L
> [int, long, long, long] LUSHR

here is a problem, LUSHR expects [..., long, int], but we have 2 longs
here. The I2L should not have happened. So I can confirm a problem here. "

Thanks!
Jason