Having this check is likely no more meaningful (it seems to have been
added ages ago), but keeping it around does not hurt either. And it
could avoid crashes in some file corruption cases e.g.
However, having it in 'lib_link' code of constraints is useless for
sure, since that data pointer may have already been accessed in the
'read_data' one. And of course, logically it belongs to 'read_data'
anyway, since it's related (and only affects) private local data, not
pointers to other IDs...
No behavioral change expected here.
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