[patch] for PR 18040

[Richard Kenner]

    What he's saying is that

       <COMPONENT_REF type struct field>

    (and all other reference nodes) would implicitly convert FIELD to TYPE,
    if that's not FIELD's intrinsic type.  I think this makes a hell of a
    lot of sense, personally.

I have no problem with that, though I suspect it's a bit of an earthquake
at this point.  Would we do it for both GENERIC and GIMPLE or just the
latter?

Note that I also think that get_inner_reference and handle_component_p
probably only need to handle VIEW_CONVERT_EXPR and not the rest of the
conversions at this point.