zephyr: device: uart: irq: panic on drop

Because this interface has registered IRQs, prevent drops.  They are
probably safe due to the use of the leaked Arc, but the data is in fact
leaked.  For now, just cause Drop to panic, as normal use won't ever
drop this.

Signed-off-by: David Brown <david.brown@linaro.org>

Author: d3zd3z

zephyr/src/device/uart/irq.rs

@@ -220,6 +220,15 @@ impl<const WS: usize, const RS: usize> UartIrq<WS, RS> {
     }
 }
 
+// TODO: It could actually be possible to implement drop, but we would need to make sure the irq
+// handlers are deregistered.  These is also the issue of the buffers being dropped.  For now, just
+// panic, as this isn't normal.
+impl<const WS: usize, const RS: usize> Drop for UartIrq<WS, RS> {
+    fn drop(&mut self) {
+        panic!("UartIrq dropped");
+    }
+}
+
 impl<const WS: usize, const RS: usize> IrqOuterData<WS, RS> {
     /// Try reading from the inner data, filling the buffer with as much data as makes sense.
     /// Returns the number of bytes actually read, or Zero if none.