nir/vec3_to_vec4: Use nir_deref_must_be

We use the same nir_deref_mode_is_in_set helper that we use in
nir_lower_vars_to_explicit_types for the same reason.  If there are any
generic pointers in play, we have to lower all generic pointer modes at
the same time or else we risk types getting out-of-sync.

Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6332>
1 file changed