Stable releases are unusable with default hhconfig on latest hhvm

[fredemmott]

HHVM 4.96

Parsing[1002] Cannot use unstable feature: coeffects_provisional [1]

vendor/hhvm/hsl/src/vec/cast.php:21:2
    19 |   <<__MaybeMutable, __OnlyRxIfImpl(Rx\Traversable::class)>>
    20 |   Traversable<T> $x,
[1] 21 | )[]: vec<T> {
    22 |   return \HH\is_vec_or_varray($x)
    23 |     /* HH_FIXME[4259] Rx doesn't understand array_unmark_legacy */

 vendor/hhvm/hsl/src/vec/async.php:91:3
    89 |   <<__AtMostRxAsFunc>>
    90 |   (function(Tv1)[_]: Awaitable<Tv2>) $async_func,
[1] 91 | )[ctx $async_func]: Awaitable<vec<Tv2>> {
    92 |   $vec = cast_clear_legacy_array_mark($traversable);
    93 |   foreach ($vec as $i => $value) {

Naming[2049] Unbound name: HH\Contexts\ctx [1]

[fredemmott]

these should be enabled by default in hhvm/hack before they are used in a stable releae of the HSL.

[fredemmott]

actually no, somethings' wrong with the version detection in hh_client - it's happy to keep talking to a somewhat older hh_server