Function panic 

pub unsafe fn panic<L: Led, W: Write + IoWrite, C: Chip, PP: ProcessPrinter>(
    leds: &mut [&L],
    writer: &mut W,
    panic_info: &PanicInfo<'_>,
    nop: &dyn Fn(),
    panic_resources: Option<&PanicResources<C, PP>>,
) -> !

Tock default panic routine.

NOTE: The supplied writer must be synchronous.

This will print a detailed debugging message and then loop forever while blinking an LED in a recognizable pattern.