#3397: :step hangs when -fbreak-on-exception is set -------------------------------------+------------------------------------- Reporter: hamish | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.2.1 Component: GHCi | Version: 7.10.1-rc2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86 Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Changes (by gelisam): * cc: hvr (added) * status: closed => new * version: 6.10.3 => 7.10.1-rc2 * resolution: worksforme => Comment: I have encountered this very old bug with GHC 7.10.0.20150123, here's a minimal test case: {{{#!hs mapLookup :: () -> () mapLookup = go where go () = () withDummyLookup :: IO a -> IO a withDummyLookup body = do mapLookup () `seq` return () body main :: IO () main = withDummyLookup (return ()) }}} To reproduce: {{{ $ ghci Example.hs *Main> :set -fbreak-on-exception *Main> :steplocal main Stopped at Example.hs:12:8-34 _result :: IO () = _ [Example.hs:12:8-34] *Main> :steplocal (hangs forever) }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/3397#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler