Re: [GHC] #15186: ghc 8.4.2 panic in profiling build

#15186: ghc 8.4.2 panic in profiling build -------------------------------------+------------------------------------- Reporter: kquick | Owner: bgamari Type: bug | Status: patch Priority: normal | Milestone: 8.6.1 Component: Profiling | Version: 8.4.2 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: T15186 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D4755, Wiki Page: | Phab:D4757 -------------------------------------+------------------------------------- Comment (by Ben Gamari ): In [changeset:"f0c1eb8b5640b0ec86b9fabb465ea5b841808d56/ghc" f0c1eb8/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="f0c1eb8b5640b0ec86b9fabb465ea5b841808d56" Conservatively estimate levity in worker/wrapper The worker/wrapper transform needs to determine the levity of the result to determine whether it needs to introduce a lambda to preserve laziness of the result. For this is previously used isUnliftedType. However, this may fail in the presence of levity polymorphism. We now instead use isLiftedType_maybe, assuming that a lambda is needed if the levity of the result cannot be determined. Fixes #15186. Test Plan: make test=T15186 Reviewers: simonpj, goldfire, tdammers Reviewed By: simonpj Subscribers: rwbarton, thomie, carter GHC Trac Issues: #15186 Differential Revision: https://phabricator.haskell.org/D4755 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15186#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler