It seems the rule compiler is not correctly checking type safety when using window operators to define rule conditions.

I defined a rule using the following code (note that I incorrectly used "time:window" to define the window, instead of "window:time"):

declare SensorReading
@role(event)
@timestamp(timestamp)
end

rule "boilers"
when
$b1: (SensorReading(sensorId == 1L && status == SensorStatus.ON) over time:window(10s))
then
....
end

The rule has been compiled and executed, but not following the correct window semantics. The forum link contains a full description of the (unexpected) behaviour I found when defining rule like this.