[patch, fortran] Fix PR 33539

[Tobias Schlüter]

Tobias Schlüter wrote:
> Thomas Koenig wrote:
>> Hello world,
>>
>> this fixes PR 33539 by not issuing a warning for strings
>> that have zero length.  Regression-tested on i686-pc-linux-gnu.
>>
>> No special test case needed; I just removed dg-warning lines from
>> the places where they occurred in the testsuite.
>>
>> OK?  (Also OK with the approach of not warning)?
> 
> When I thought about this bug, I decided against this approach, as I 
> thought it might suppress valid warnings.
> 
> The problem with doing real fix is that once we resolve character 
> lengths, we don't know where they're coming from, i.e. we can't tell if 
> they're from a module or whether they belong to PARAMETERs. 
> Unfortunately, we can't add this information to the gfc_charlen 
> structures, as they may be referred to from several objects.
> 
> If other people agree that this is the right way of solving this, I'm by 
> no means opposed to it, though.

I see that other people have already agreed.  Please go ahead, Thomas :-)

- Tobi