Local var reference in rule body can cause Null Pointer Exception during trigger injection if local var stack includes longs/doubles

If a ruel refers to a local variable in scope at the trigger location then the injected trigger code needs to load it and pass it as a parameter to the code in the rule body. The computation of the relevant local var slot appears to go wrong if any of the preceding local variables are longs or doubles. It seems that the calculation is only allowing for one slot when these values actually employ two slots.