How can you miss an error check? Either you have used try and therefor there has been a check for errors. Or you have not used try and therefor you had to ass

How can you miss an error check? Either you have used try and therefor there has been a check for errors. Or you have not used try and therefor you had to assign to err and therefor you have to use a check for errors. Any assignment to err indicates you need to check for errors just like it is currently.