#9732: Pattern synonyms and unboxed values -------------------------------------+------------------------------------- Reporter: monoidal | Owner: cactus Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Unknown Type of failure: Compile- | Blocked By: time crash | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by cactus): Yes, I've found `voidPrimId`/`voidArgId` meanwhile, and I have a working implementation pushed to `wip/T9732` just now. However, I had to split the matcher into two, since otherwise I can't decide when to have the extra arg, since the result type is completely unknown at matcher generation time. So for now, I've went with {{{ Main.$mPAT :: forall r. GHC.Prim.Int# -> r -> r -> r Main.$m#PAT :: forall (r :: #). GHC.Prim.Int# -> (GHC.Prim.Void# -> r) -> (GHC.Prim.Void# -> r) -> r }}} so that takes care of using pattern synonyms when the _result_ type is unlifted: both of these now compile lint-free, and give the expected behaviour: {{{ f PAT = 42# g PAT = (42 :: Int) }}} So the only remaining TODO should be to add this extra `Void#` argument to the generated wrappers when there are no other arguments and the pattern type is unlifted. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9732#comment:13 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler