Should a disabled warning be allowed to be promoted to an error(Bugzilla PR 70275)?

[Jeff Law]

On 03/31/2016 09:39 PM, Martin Sebor wrote:
> On 03/31/2016 10:30 AM, Segher Boessenkool wrote:
>> On Mon, Mar 28, 2016 at 04:32:50PM -0600, Martin Sebor wrote:
>>> On 03/28/2016 01:56 PM, Florian Weimer wrote:
>>>>> In Bugzilla PR # 70275, Manuel López-Ibáñez reports that even though
>>>>> he provides the "-Werror=return-type" option, the compiler doesn't
>>>>> flag the warning/error about a control reaching the end of a non-void
>>>>> function, due to the presence of the "-w" option.  He points out that
>>>>> clang++ wtill flags the promoted warning even though warnings are
>>>>> inhibited.
>>>>
>>>> I think -w is ordered with respect to the other warning obtions, and
>>>> -w inhibits previously requested warnings, and future -W flags may
>>>> enable other warnings.  With this in mind, I agree that the current
>>>> GCC behavior is consistent and probably not a bug.
>>>
>>> The general rule of thumb documented in the manual is that more
>>> specific options take precedence over more general ones, regardless
>>> of where they appear on the command line:
>>
>> Currently, -w is a nice easy quick way of shutting up all warnings
>> whenever they are getting in the way.  Let's keep it that way.
>
> I agree that having a knob to suppress all warnings can be useful.
>
> At the same time, having the ability to do what PR 70275 asks for
> (i.e., suppress only warnings that have not be been explicitly
> enabled or elevated to errors) can be handy as well.  If it's
> preferable to keep -w unchanged, providing a new option to do it
> might be worth considering.
Given the long standing behavior of -w, I think it should remain unchanged.

jeff