#13695: Highly nested UNPACKed data causes panic ----------------------------------------+--------------------------------- Reporter: ryanreich | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 Keywords: | Operating System: Linux Architecture: Unknown/Multiple | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: 3990 Differential Rev(s): | Wiki Page: ----------------------------------------+--------------------------------- See attached source files. I get the following error: {{{ [3 of 3] Compiling Data.BigWord ( src/Data/BigWord.hs, .stack- work/dist/x86_64-linux/Cabal-2.0.0.0/build/Data/BigWord.o ) ghc: panic! (the 'impossible' happened) (GHC version 8.2.0.20170505 for x86_64-unknown-linux): urk! lookup local fingerprint D:R:DoubleWordDoubleWord2 [cESifd :-> (BigWord2, acd0b93ce6ccc191df910f3c0527af52), cESife :-> (BigWord3, c2394bb5a6246cea8260b764c4645609), cESiqK :-> (BigWord4, dfeb99d5c409e91fe7084935101bb1a8), cESiqT :-> (R:DoubleWordDoubleWord3, 00000000000000000000000000000000), cESiqV :-> (D:R:DoubleWordDoubleWord4, 00000000000000000000000000000000), cESir1 :-> (D:R:BigWord4, 7d2736129b3a85c7e71bc1954bb41ec0), dESiqK :-> (BigWord4, d51a0117843c625086a534a6e4b47d85), iESiqK :-> (BigWord4, 139d5d98471af07fbafb30541b5ec225), iESiqX :-> ($WBigWord4, df51c2cc8c85fdd30898a16f2568c91a)] Call stack: CallStack (from HasCallStack): prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1134:58 in ghc:Outputable callStackDoc, called at compiler/utils/Outputable.hs:1138:37 in ghc:Outputable pprPanic, called at compiler/iface/MkIface.hs:508:37 in ghc:MkIface }}} I need to use ghc-8.2.1 because it seems to be the earliest version that contains the fixes in [https://ghc.haskell.org/trac/ghc/ticket/3990], without which the UNPACKs will be ignored. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13695 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler