#13330: forkIO has inconsistent behavior under optimization -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Core Libraries | Version: 8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D3189 Wiki Page: | -------------------------------------+------------------------------------- Comment (by dfeuer): Simon, I definitely think more needs to be done in this area. I'm not yet convinced that `catchException` is really useful at the moment; we should probably just use `catch`, and force exactly what we need to. I am also concerned about `catchRetry#` and `catchSTM#` (see #13357). However, I just realized that we probably ''can'' do something a bit more interesting with `catch`. In particular, something definitely used by ''both'' the action ''and'' the recovery function can safely be forced in advance. So if we see, for example, {{{#!hs f x = (x `seq` ...) `catch` \e -> x `seq` ... }}} then we can surely use {{{#!hs f x = IO $ \s -> x `seq` unIO (... `catch` ...) }}} I don't yet know enough about the demand analysis algorithm to see how to do this, but it seems rather likely to be worth trying. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13330#comment:14 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler