#15503: interpreter: sequence_ (replicate 100000000 (return ())) gobbles up memory -------------------------------------+------------------------------------- Reporter: int-e | Owner: osa1 Type: bug | Status: new Priority: high | Milestone: 8.8.1 Component: GHCi | Version: 8.5 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 osa1): Simon, do you have any guesses on what may be retaining those PAPs? Btw, here's the Core generated for this expression: (output of -ddump- simpl) {{{ GHC.Base.bindIO @ () @ [()] (GHC.GHCi.ghciStepIO @ GHC.Types.IO GHC.GHCi.$fGHCiSandboxIOIO @ () (Data.Foldable.sequence_ @ [] @ GHC.Types.IO @ () Data.Foldable.$fFoldable[] GHC.Base.$fMonadIO (GHC.List.replicate @ (GHC.Types.IO ()) (GHC.Types.I# 100000000#) (GHC.Base.return @ GHC.Types.IO GHC.Base.$fMonadIO @ () GHC.Tuple.())))) (\ (it_a1UK :: ()) -> GHC.Base.returnIO @ [()] (GHC.Types.: @ () it_a1UK (GHC.Types.[] @ ()))) }}} More readable version: {{{ GHC.Base.bindIO (ghciStepIO <the expression>) (\i -> GHC.Base.returnIO [i]) }}} The Core identical to the Core generated by GHC 7.10. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15503#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler