[Bug c++/77656] 64-bit integral template parameter gets incorrectly sized as 32-bits

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77656

--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #1)
> Perhaps tsubst of TEMPLATE_PARM_INDEX instead of just
> return convert_from_reference (unshare_expr (arg));
> also convert it to the TEMPLATE_PARM_INDEX's type (if it is integral type
> only, or when?)?

That would work, but the arg ought to already have the right type from
convert_nontype_argument.  I'll take a look.