#9009: Confusing error message when loading package with TH ------------------------------------+------------------------------------- Reporter: jstolarek | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Package system | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: Other Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- I got this error message when compiling a file that calls Template Haskell function from `singletons` package: {{{ [1 of 1] Compiling Splices ( Splices.hs, Splices.o ) Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Loading package transformers-0.3.0.0 ... linking ... done. Loading package pretty-1.1.1.1 ... linking ... done. Loading package array-0.5.0.0 ... linking ... done. Loading package deepseq-1.3.0.2 ... linking ... done. Loading package containers-0.5.5.1 ... linking ... done. Loading package mtl-2.1.2 ... linking ... done. Loading package template-haskell ... linking ... done. Loading package syb-0.4.1 ... linking ... done. Loading package th-desugar-1.4.0 ... linking ... done. Loading package singletons-1.0 ... <command line>: can't load .so/.DLL for: /home/killy/.cabal/lib/x86_64-linux- ghc-7.8.2/singletons-1.0/libHSsingletons-1.0-ghc7.8.2.so (/home/killy/.cabal/lib/x86_64-linux- ghc-7.8.2/singletons-1.0/libHSsingletons-1.0-ghc7.8.2.so: undefined symbol: singletonszm1zi0_DataziSingletonsziSingleziMonad_lookupProxy1_info) }}} After some investigation it turned out that the module Data.Singletons.Single.Monad was not listed in singletons.cabal file - neither under exported-modules nor other-modules - when the package was installed. The error message is mostly confusing. It would be good to at least get a hint on the possible cause. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9009 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler