#16092: Bug when trying to combine two lists -------------------------------------+------------------------------------- Reporter: sutbult | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Keywords: | Operating System: MacOS X Architecture: x86_64 | Type of failure: Building GHC (amd64) | failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I want to write a function that takes two lists and returns a list that includes every possible combination of elements from the two given lists, using a given function. I thought that this code would work: {{{#!hs combine :: (a -> b -> c) [a] -> [b] -> [c] combine fn alist blist = [fn a b | a <- alist, b <- blist] }}} However, when compiling, this message arises from GHC: Glasgow Haskell Compiler, Version 8.2.1, stage 2 booted by GHC version 7.10.3 Using binary package database: /Library/Frameworks/GHC.framework/Versions/8.2.1-x86_64/usr/lib/ghc-8.2.1/package.conf.d/package.cache Using binary package database: /Users/samuelutbult/.ghc/x86_64-darwin-8.2.1/package.conf.d/package.cache package flags [] loading package database /Library/Frameworks/GHC.framework/Versions/8.2.1-x86_64/usr/lib/ghc-8.2.1/package.conf.d loading package database /Users/samuelutbult/.ghc/x86_64-darwin-8.2.1/package.conf.d wired-in package ghc-prim mapped to ghc-prim-0.5.1.0 wired-in package integer-gmp mapped to integer-gmp-1.0.1.0 wired-in package base mapped to base-4.10.0.0 wired-in package rts mapped to rts wired-in package template-haskell mapped to template-haskell-2.12.0.0 wired-in package ghc mapped to ghc-8.2.1 wired-in package dph-seq not found. wired-in package dph-par not found. package flags [] loading package database /Library/Frameworks/GHC.framework/Versions/8.2.1-x86_64/usr/lib/ghc-8.2.1/package.conf.d loading package database /Users/samuelutbult/.ghc/x86_64-darwin-8.2.1/package.conf.d wired-in package ghc-prim mapped to ghc-prim-0.5.1.0 wired-in package integer-gmp mapped to integer-gmp-1.0.1.0 wired-in package base mapped to base-4.10.0.0 wired-in package rts mapped to rts-1.0 wired-in package template-haskell mapped to template-haskell-2.12.0.0 wired-in package ghc mapped to ghc-8.2.1 wired-in package dph-seq not found. wired-in package dph-par not found. *** Chasing dependencies: Chasing modules from: *Combine.hs !!! Chasing dependencies: finished in 0.69 milliseconds, allocated 0.222 megabytes Stable obj: [] Stable BCO: [] Ready for upsweep [NONREC ModSummary { ms_hs_date = 2018-12-23 17:18:05.830132761 UTC ms_mod = Main, ms_textual_imps = [(Nothing, Prelude)] ms_srcimps = [] }] *** Deleting temp files: Deleting: compile: input file Combine.hs *** Checking old interface for Main (use -ddump-hi-diffs for more details): [1 of 1] Compiling Main ( Combine.hs, Combine.o ) *** Parser [Main]: !!! Parser [Main]: finished in 1.05 milliseconds, allocated 0.171 megabytes *** Renamer/typechecker [Main]: *** Deleting temp files: Deleting: *** Deleting temp dirs: Deleting: ghc: panic! (the 'impossible' happened) (GHC version 8.2.1 for x86_64-apple-darwin): repSplitAppTys a_anL[sk:1] b_anM[sk:1] -> c_anN[sk:1] [] Call stack: CallStack (from HasCallStack): prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1133:58 in ghc:Outputable callStackDoc, called at compiler/utils/Outputable.hs:1137:37 in ghc:Outputable pprPanic, called at compiler/types/Type.hs:808:9 in ghc:Type Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16092 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler