Accessing Null Reference (ANR)

Description:

ANR detects cases where evaluation of a field reference expression will result in a System.NullReferenceException being thrown. ANR is reported whenever a non-static field of an object or array is accessed and the left operand of the . (field access) operator has the null value.

Incorrect:

public void PrintMessage(Message msg) {
    if (msg != null) {
        msg.Print();
    } else {
        Console.WriteLine(msg.ToString() + " is null");
    }
}

Correct:

public void PrintMessage(Message msg) {
    if (msg != null) {
        msg.Print();
    } else {
        Console.WriteLine("msg is null");
    }
}