Hi Mikael!

Am 04.03.23 um 14:56 schrieb Mikael Morin:
> I have found the time finally.  It's not as bad as it seemed.  See below.
>
>> diff --git a/gcc/fortran/decl.cc b/gcc/fortran/decl.cc
>> index eec0314cf4c..72d8c6f1c14 100644
>> --- a/gcc/fortran/decl.cc
>> +++ b/gcc/fortran/decl.cc

>> +      sym->attr.pointer = CLASS_DATA(sym)->attr.class_pointer;
>> +      sym->attr.allocatable = CLASS_DATA(sym)->attr.allocatable;
>> +      sym->attr.dimension = CLASS_DATA(sym)->attr.dimension;
>> +      sym->attr.codimension = CLASS_DATA(sym)->attr.codimension;
>> +      if (as && CLASS_DATA (sym)->as)
>> +    sym->as = gfc_copy_array_spec (CLASS_DATA (sym)->as);
>
> Here the condition on 'CLASS_DATA(sym)->as' makes obviously sense, but I
> don't see why there is also a condition on 'as'.
>
> For example, if the array spec has been previously set on the class
> container's first component, and there is no array spec information in
> the current statement (i.e. as == NULL), sym->as will remain NULL, and a
> non-array class container will be built in gfc_build_class_symbol below.

Very good catch!  Indeed, this fixes the testcase variations.


>> @@ -8807,6 +8785,27 @@ attr_decl1 (void)
>>        goto cleanup;
>>      }
>>
>> +  if (sym->ts.type == BT_CLASS && sym->ts.u.derived->attr.is_class
>> +      && !as && !current_attr.pointer && !current_attr.allocatable
>> +      && !current_attr.external)
>> +    {
>> +      sym->attr.pointer = 0;
>> +      sym->attr.allocatable = 0;
>> +      sym->attr.dimension = 0;
>> +      sym->attr.codimension = 0;
>
>> +      gfc_free_array_spec (sym->as);
> sym->as should probably be reset to NULL here.

Done.

> Maybe both calls to gfc_free_array_spec here and to gfc_copy_array_spec
> above can be avoided by doing a simple pointer copy?

I tried that, but this produced a crash with a double-free.

The attached revised version uses the above proven changes,
and extends the new testcase class_74.f90 by variations of
the failures remaining with version 1 so that different
codepaths are tested.

Regtested again on x86_64-pc-linux-gnu.

Any further comments?

Thanks for your very helpful review!

Harald