Let me confirm the requirement of Rule 16.1

[Steve Montgomery]

I agree that the code isn't well formed. Rule 15.4 prevents more than one break or goto from terminating a loop. Rule 15.5 prevents more than one return from a function. So maybe it is anomalous that there is no rule to prevent more than one break or goto from terminating a switch-clause.

In the example you gave, Rule 2.1 was able to detect the poor structure. However, I think there are other ways in which more than one break can be used to terminate a switch-clause without violating any rules. For example:

Code:

switch( x )
{
case 10:
if (y == 10) {
  rtn = 20;
  break;
}
rtn = 50;
break;
default:
break;
}
return rtn;
}

In MISRA C:2004, break, goto and possibly return were not allowed to appear within the body of a switch statement so neither this example nor your example would be permitted. That restriction seems to have been removed in MISRA C:2012 but it isn't mentioned in the rule mapping (https://misra.org.uk/forum/viewtopic.php?f=241&t=1256) which makes me wonder whether it was intended.

I cannot give a formal answer because I don't represent the MISRA C Working Group. We will need to wait for the formal response.