[cfe-dev] Why these problems below were not found by Clang Static Analyzer?

[Jordan Rose]

On Mar 14, 2014, at 11:31 , Nico Weber <thakis at chromium.org> wrote:

> On Fri, Mar 14, 2014 at 10:00 AM, Jordan Rose <jordan_rose at apple.com> wrote:
> The analyzer tries not to give results that are already covered by regular Clang warnings. This is sometimes problematic, since the Clang warnings may not be on by default. Nevertheless...
> 
> On Mar 11, 2014, at 19:53 , apache <ehcapa at qq.com> wrote:
> 
>> ----------------------------------------------------------------------
>> 1.case without break
>> e.g.
>> int test(const int n) {
>>     int ret = 0;
>>     switch(n) {
>>     case 1:
>>         ret = 1;
>>         break;
>>     case 2:
>>         ret = 2; // this case branch has no 'break' statement.(coverity gived a warning here, but Clang didn't)
>>     default:
>>         break;
>>     }
>>     return ret;
>> }
> 
> This is supposed to be -Wimplicit-fallthrough, but I don't see it working either! Richard, do you know what's going on here?
> 
> In general, -Wimplicit-fallthrough does warn on this, which I mostly consider a bug: Falling through to a default: branch that contains nothing but a break is a) safe b) relatively common, so I think this shouldn't warn. (But it currently does, at least in blink.)

I tried adding a "ret = 3" too, and it still didn't warn. I'm not sure why.

Jordan

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