The requirement for a final default clause is defensive programming. The clause should either take appropriate action, or contain a
suitable comment as to why no action is taken. Even when the switch covers all current values of an enum, a
default case should still be used because there is no guarantee that the enum won’t be extended.
Noncompliant code example
int foo = 42;
switch (foo) // Noncompliant
{
case 0:
Console.WriteLine("foo = 0");
break;
case 42:
Console.WriteLine("foo = 42");
break;
}
Compliant solution
int foo = 42;
switch (foo) // Compliant
{
case 0:
Console.WriteLine("foo = 0");
break;
case 42:
Console.WriteLine("foo = 42");
break;
default:
throw new InvalidOperationException("Unexpected value foo = " + foo);
}
