#14519: Exponential runtime performance regression in GHC 8.2 + Data.Text.Lazy + Text.RE.TDFA -------------------------------------+------------------------------------- Reporter: ntc2 | Owner: tdammers Type: bug | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 8.2.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Runtime | Test Case: performance bug | https://github.com/ntc2/ghc-8.2.1 | -regex-lazy-text- | bug/tree/07b7bb32c6e90e8f2d2eada4b59943f37e632d53 Blocked By: | Blocking: Related Tickets: #13745, #14564 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by tdammers): Right, didn't think to try without the `w-` and the `-2`. On my setup, there's no `next` in `Text/Regex/TDFA/NewDFA`, but four similar modules underneath it (`Engine`, `Engine_FA`, `Engine_NC`, and `Engine_NC_FA`) do have such a function defined in a let binding. It seems that the `Lazy` module ends up using the one in `Engine` (without any suffix), via `execMatch`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14519#comment:18 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler