message: improve panic error message
diff: @@ -300,10 +300,20 @@ impl Runtime {
  if error.from == error.to {
  // All queries in the cycle is local
  - let start_index = query_stack
  + let start_index = match query_stack
  .iter()
  .rposition(|active_query| active_query.database_key_index == database_key_index)
  - .unwrap();
  + {
  + Some(i) => i,
  + None => panic!(
  + "did not find {:?} on the stack: {:?}",
  + database_key_index,
  + query_stack
  + .iter()
  + .map(|s| s.database_key_index)
  + .collect::<Vec<_>>()
  + ),
  + };
  let mut cycle = Vec::new();
  let cycle_participants = &mut query_stack[start_index..];
  for active_query in &mut *cycle_participants {
  