#12096: Attach stacktrace information to SomeException -------------------------------------+------------------------------------- Reporter: ndtimofeev | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: Component: Core Libraries | Version: 8.0.1 Resolution: | Keywords: Exceptions Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by ndtimofeev): We can substitute `?callStack` in `catch` from actual value to value from caught exception value. {{{#!hs catch' :: Exception e => IO a -> (HasCallStack => e -> IO a) -> IO a catch' eval handler = eval `catch` \err@(SomeExceptionWithStack stack _) -> let ?callStack = stack in case fromException err of Just ex -> handler ex _ -> throw err }}} Now all `throw` called from `catch` handler will be implicit rethrow. It looks like a ugly hack and required Rank2Types. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12096#comment:18 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler