#13331: Worker/wrapper can lead to sharing failure -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by dfeuer): `ptrEq` is indeed a thin wrapper around `reallyUnsafePtrEquality#`: {{{#!hs ptrEq :: a -> a -> Bool ptrEq x y = tagToEnum# (reallyUnsafePtrEquality# x y) }}} If it's really hard to work this out automatically, I wonder if it could be made a little easier with a pragma. I'd be satisfied if I could write something like {{{#!hs go :: Ord k => {-# NOUNPACK #-} k -> k -> a -> Map k a -> Map k a }}} to indicate that GHC should not unbox the first argument. Would that make it easier to avoid the problem? I'd hate to leave something as fragile- looking as my workaround hack in `containers` forever. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13331#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler