message: Help detect this programming error in development.
diff: @@ -27,6 +27,7 @@ impl HostFunctionFlag {
  pub(super) fn enter_host_function_scope(&self) -> ScopedHostFunctionFlag {
  let new_count = self.counter.get().checked_add(1).unwrap_or_else(|| {
  error!("checked_add failure in host function flag counter");
  + debug_assert!(false, "checked_add failure in host function flag counter");
  u64::MAX
  });
  self.counter.set(new_count);
  @@ -44,6 +45,7 @@ impl Drop for ScopedHostFunctionFlag {
  fn drop(&mut self) {
  let new_count = self.counter.get().checked_sub(1).unwrap_or_else(|| {
  error!("checked_sub failure in host function flag counter");
  + debug_assert!(false, "checked_sub failure in host function flag counter");
  0
  });
  self.counter.set(new_count);
  