#9291: Don't reconstruct sum types if the type subtly changes -------------------------------------+------------------------------------- Reporter: schyler | Owner: nomeata Type: feature request | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2871 Wiki Page: | -------------------------------------+------------------------------------- Comment (by heisenbug): Replying to [comment:47 nomeata]:
Looking at the tests, I do not see Either x y <-> Maybe y coercions. Are these supposed to be done?
Are you referring to treating a `Just x` directly `Right x`, i.e. using similarly looking constructors at a different type? That is not included here, and it is not clear whether we actually want it done. If you think we do, please open a new ticket for it.
Yes, that is what I mean. They would be memory-layout compatible. I'll ponder a bit more, and if I still think it's a good idea, I'll follow up with a ticket. Thanks for doing this! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9291#comment:48 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler