[GHC] #12696: Exception gives not enough information to be useful

#12696: Exception gives not enough information to be useful -------------------------------------+------------------------------------- Reporter: flip101 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: exception | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I was told in #haskell @freenode to report this as a bug. I have a program that throws exceptions and tried debugging the problem within ghci and also outside of ghci with these commands: {{{ stack build --ghc-options '-rtsopts -fprof-auto -fprof-auto-calls' --executable-profiling stack exec -- vhdl +RTS -xc }}} {{{#!hs tfComment :: Data from => from -> from tfComment = transformBi tf where tf (Comment ((pos_c, c), (pos_s, s))) = Comment $ ((pos_c, T.concat ["--", c]), (pos_s, s)) tf a = a zeroPos :: Data from => from -> from zeroPos = transformBi zp where zp sp@(M.SourcePos _ _ _) = sp { M.sourceName="", M.sourceLine=unsafePos 1, M.sourceColumn=unsafePos 1} zp x = x -- (a)dd (e)xtended(i)dentifier (s)laches aeis :: Data from => from -> from aeis = transformBi x where x (IExtended a) = let updated_text :: Text updated_text = T.concat ["\\", snd $ t_text a, "\\"] in IExtended $ a {t_text = (fst $ t_text a, updated_text)} x a = a bla = something.. where parser_prop :: ContextClause -> Bool parser_prop = \x -> (transformIn <$> Right x) == (transformOut <$> parseSource parser $ T.toStrict . printSource $ transformIn x) transformIn ast = zeroPos ast transformOut ast = tfComment $ aeis $ zeroPos ast }}} ghci trace {{{ λ> :trace main Stopped in <exception thrown>, <unknown> _exception :: e = _ λ> :back Logged breakpoint at Main.hs:95:13-26 _result :: from -> from tf :: Comment -> Comment λ> :list 94 tfComment :: Data from => from -> from 95 tfComment = transformBi tf -- transformBi tf highlighted here 96 where tf (Comment ((pos_c, c), (pos_s, s))) = Comment $ ((pos_c, T.concat ["--", c]), (pos_s, s)) λ> :back Logged breakpoint at Main.hs:242:28-57 _result :: from ast :: from λ> :list 241 transformIn ast = zeroPos ast 242 transformOut ast = tfComment $ aeis $ zeroPos ast -- tfComment $ aeis $ zeroPos ast highlighted here 243 λ> :force ast ast = Right [] λ> transformIn (Right []) Right [] λ> transformOut (Right []) Right [] λ> zeroPos (Right []) Right [] λ> aeis (Right []) Right [] λ> tfComment (Right []) Right [] }}} run with profiling options (this was aborted at some point) {{{ » stack exec -- vhdl +RTS -xc *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Data.CAF --> evaluated by: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2028_r3oe6 --> evaluated by: Data.HashMap.Base.toList', called from Data.HashMap.Base.equal, called from Data.HashMap.Base.==, called from Data.Generics.Uniplate.Internal.Data.fixEq, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2028_r3oe6 *** Exception (reporting due to +RTS -xc): (THUNK_STATIC), stack trace: Data.Generics.Uniplate.Internal.Data.uniplateVerbose, called from Data.Generics.Uniplate.Internal.Data.CAF:uniplateVerbose --> evaluated by: Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2028_r3oe6 --> evaluated by: Data.Generics.Uniplate.Internal.Data.fromOracle, called from Data.Generics.Uniplate.Internal.Data.biplateData, called from Data.Generics.Uniplate.Data.biplate, called from Main.tfComment, called from Main.qcrp.transformOut, called from Main.qcrp.parser_prop, called from Main.qcrp.parser_prop, called from Main.qc2.logInput, called from Main.qc2.logInput, called from Main.qc2.logInput, called from Main.qc2, called from Test.QuickCheck.Property.forAllShrink.\.\, called from Test.QuickCheck.Property.property, called from Test.QuickCheck.Test.quickCheckWithResult.property', called from Test.QuickCheck.Test.quickCheckWithResult.\, called from Test.QuickCheck.Text.withNullTerminal, called from Test.QuickCheck.Test.quickCheckWithResult, called from Main.qc2, called from Main.qcrp, called from Main.ntc *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2025_r3oe3 --> evaluated by: Data.HashMap.Base.toList', called from Data.HashMap.Base.equal, called from Data.HashMap.Base.==, called from Data.Generics.Uniplate.Internal.Data.fixEq, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2025_r3oe3 *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2022_r3oe0 --> evaluated by: Data.HashMap.Base.toList', called from Data.HashMap.Base.equal, called from Data.HashMap.Base.==, called from Data.Generics.Uniplate.Internal.Data.fixEq, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2022_r3oe0 *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl1945_r3oc9 *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.descend.answer, called from Data.Generics.Uniplate.Data.descend, called from Data.Generics.Uniplate.Operations.transform.g, called from Data.Generics.Uniplate.Operations.transform, called from Main.CAF:answer6_r3ocg --> evaluated by: Data.HashMap.Base.toList', called from Data.HashMap.Base.equal, called from Data.HashMap.Base.==, called from Data.Generics.Uniplate.Internal.Data.fixEq, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.descend.answer, called from Data.Generics.Uniplate.Data.descend, called from Data.Generics.Uniplate.Operations.transform.g, called from Data.Generics.Uniplate.Operations.transform, called from Main.CAF:answer6_r3ocg *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.descend.answer, called from Data.Generics.Uniplate.Data.descend, called from Data.Generics.Uniplate.Operations.transform.g, called from Data.Generics.Uniplate.Operations.transform, called from Main.CAF:answer7_r3ocp --> evaluated by: Data.HashMap.Base.toList', called from Data.HashMap.Base.equal, called from Data.HashMap.Base.==, called from Data.Generics.Uniplate.Internal.Data.fixEq, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.descend.answer, called from Data.Generics.Uniplate.Data.descend, called from Data.Generics.Uniplate.Operations.transform.g, called from Data.Generics.Uniplate.Operations.transform, called from Main.CAF:answer7_r3ocp *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.descend.answer, called from Data.Generics.Uniplate.Data.descend, called from Data.Generics.Uniplate.Operations.transform.g, called from Data.Generics.Uniplate.Operations.transform, called from Main.CAF:answer8_r3ocy --> evaluated by: Data.HashMap.Base.toList', called from Data.HashMap.Base.equal, called from Data.HashMap.Base.==, called from Data.Generics.Uniplate.Internal.Data.fixEq, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.descend.answer, called from Data.Generics.Uniplate.Data.descend, called from Data.Generics.Uniplate.Operations.transform.g, called from Data.Generics.Uniplate.Operations.transform, called from Main.CAF:answer8_r3ocy ^C^C^C^C }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12696 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler