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Re: [Patch, Fortran, OOP] PR 56261: seg fault call procedure pointer on polymorphic array


2013/4/7 Tobias Burnus <burnus@net-b.de>:
>>> Thus, the only place where the check can be is for:
>>>
>>>    f => ff
>>>
>>> In your example, the explicit interface of "ff" is known thus it should
>>> be
>>> testable at resolution time of the proc-pointer assignment.
>>
>> Right. However, strictly speaking, the pointer assignment as such is
>> probably valid. But of course there is not much one can do with the
>> proc-ptr afterwards, if it's invalid to call it ...
>
>  Well, if one doesn't want to error on it, one can still warn. However, the
> following states that it is invalid:
>
> "If the characteristics of the pointer object or the pointer target are such
> that an explicit interface is required, both the pointer object and the
> pointer target shall have an explicit interface." (F2008, para 4 of "7.2.2.4
> Procedure pointer assignment")

Ok, here is an updated patch, which does the discussed checking for
procedure pointer assignments. For this I have introduced a new
function 'gfc_explicit_interface_required', which checks all the items
in F08:12.4.2.2 and is loosely based on the present checks in
'resolve_global_procedure' (which are replaced by the new function).

I hope the general idea of the patch is ok and the error messages are
sufficiently comprehensible.

One leftover problem: The patch currently fails on the auto_char_len_4
test case, which is not being rejected any more. Actually I'm not
fully convinced that the dg-errors there are correct: If the EXTERNAL
statements in auto_char_len_{1,2} do not trigger an "explicit
interface required" warning, I don't see why the ones in
auto_char_len_4 should. Maybe the errors should not be about requiring
an explicit interface, but rather about a mismatch in the interface
(constant vs variable char len)?

Cheers,
Janus

Attachment: pr56261_v4.diff
Description: Binary data

Attachment: proc_ptr_40.f90
Description: Binary data


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