Deprecate par#
par#
primop was supposed to be deprecated in favor of spark#
(se #15227 (comment 154293)), however it's still used in GHC.Conc.Sync.par
and it's not clear how to replace it with spark#
(see !5548 (comment 347791)).
We undeprecated it in !5548 to support deprecation warnings on primops. If we manage to remove its use in ghc-internal/base, we may consider deprecating it again.