message: Use `shell.variables.set_var()` for setting the exit status in other areas
diff: @@ -433,9 +433,11 @@ impl FlowLogic for Shell {
  Statement::Error(number) => self.previous_status = number,
  Statement::Let(action) => {
  self.previous_status = self.local(action);
  + self.variables.set_var("?", &self.previous_status.to_string());
  }
  Statement::Export(action) => {
  self.previous_status = self.export(action);
  + self.variables.set_var("?", &self.previous_status.to_string());
  }
  Statement::While {
  expression,
  @@ -839,9 +841,11 @@ impl FlowLogic for Shell {
  Statement::Error(number) => shell.previous_status = number,
  Statement::Let(action) => {
  shell.previous_status = shell.local(action);
  + shell.variables.set_var("?", &shell.previous_status.to_string());
  }
  Statement::Export(action) => {
  shell.previous_status = shell.export(action);
  + shell.variables.set_var("?", &shell.previous_status.to_string());
  }
  Statement::While {
  expression,
  