[Patch, fortran] Fix ICE with class array references.

[Paul Richard Thomas]

Dear Mikael,

This...

> I have chosen to make it a separate function instead of fixing
> gfc_add_component_ref, so that it can be reused later (maybe...) even if we
> don't want to add a "_data", or "_vptr" or ... component.

...is exactly what I had a mind to do, once clear of regression
fixing.  Indeed, it is exactly in the spirit of the comment that you
have now eliminated in trans-expr.c

> W.R.T. the code itself, I think it is rather straightforward.  There is an
> odd thing to prevent a regression in class_41.f03.  See the big comment in
> class_data_ref_missing.
>
>
> Regression tested on x86_64-unknown-freebsd9.0.  OK for trunk?

Yes, indeed! OK for trunk.

Many thanks for the patch.  This makes for a rather complete
implementation of OOP.  I guess that the next step should be the
implementation of unlimited polymorphic objects.

Cheers

Paul