#10327: Devise workaround for how infinite types prevent closed type family reduction -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by simonpj): I must be missing something. `Inf f (f :+: g)` will certainly reduce for any ground `f` (such as `True` or `False`) because then the call will be apart from the first equation so the second can fire. If `f` is not ground, then it'll still reduce, if `f` is anything other than `f2 :+: g`, for the same reason. If `f` is a variable then yes the reduction is stuck, but that seems fair enough. Reducing it to {{{f `Seq` rhs}}} doesn't get us any further forward (e.g. if we want to unify this with another type) but it does add real new complication. Very unconvinced. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10327#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler