#13330: forkIO has inconsistent behavior under optimization -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: 8.2.1 Component: Core Libraries | Version: 8.1 Resolution: fixed | Keywords: Exceptions 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 simonpj): I'm looking at this exception-semantics stuff again, as I try to make sense of the nested CPR stuff #1600 and Phab:D4244. I'm puzzled. * The strrictness analyser has quite a bit of complexity around `ThrowsExn`. * `ThrowsExn` only differs from `Diverges` if the `ExnStr` flag is set to `ExnStr` * And the only place that happens is in `Demand.catchArgDmd` * The only place `catchArgDmd` is used is in `primops.txt.pp`. Originally, in the patch for #11222, `catchArgDmd` was used for the first arg of `catch#`, `catchSTM#` and `catchRetry#`. * But the patch in this ticket removed two of those three; now only `catchRetry#` uses the `catchArgDmd` thing. It loosk t me as if `catchRetry#` was left out by mistake. Right, David? And if so, that's the last use of `catchArgDmd` and I think that all the tricky `ThrowsExn` machinery can disappear. Incidentally, here's the amazing history of the strictness of `catch#` * Dec 13: 0558911f91c: catch# gets a strictness signature with `lazyApply1Dmd` * Jul 15: 7c0fff41789: catch# goes from `lazyApply1Dmd` to `strictApply1Dmd` * Dec 15: 28638dfe79e: catch# goes from `strictApply1Dmd` to `lazyApply1Dmd`. Trac #10712 * Jan 16: 9915b656440: catch# goes from `lazyApply1Dmd` to `catchArgDmd`, and result goes from `botRes` to `exnRes` Trac #11222. * Mar 17: 701256df88c: catch# goes from 'catchArgDmd` to `lazyApply1Dmd`. This ticket #13330. See also `Note [Strictness for mask/unmask/catch]` in `primops.txt/pp`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13330#comment:20 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler