August 2017 - ghc-tickets

[GHC] #8281: The impossible happened: primRepToFFIType
by GHC 21 Sep '18

21 Sep '18

#8281: The impossible happened: primRepToFFIType -----------------------------------+--------------------------------------- Reporter: tibbe | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time crash Unknown/Multiple | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | -----------------------------------+--------------------------------------- I ran into this error while trying to use GHCi on the hashable package: {{{ $ cabal repl Preprocessing library hashable-1.2.0.10... GHCi, version 7.6.2: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Loading package array-0.4.0.1 ... linking ... done. Loading package deepseq-1.3.0.1 ... linking ... done. Loading package bytestring-0.10.0.2 ... linking ... done. Loading package text-0.11.3.1 ... linking ... done. Loading object (static) dist/build/cbits/fnv.o ... done Loading object (static) dist/build/cbits/getRandomBytes.o ... done final link ... done [1 of 4] Compiling Data.Hashable.RandomSource ( Data/Hashable/RandomSource.hs, interpreted ) [flags changed] [2 of 4] Compiling Data.Hashable.Class ( Data/Hashable/Class.hs, interpreted ) [flags changed] ghc: panic! (the 'impossible' happened) (GHC version 7.6.2 for x86_64-apple-darwin): primRepToFFIType Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8281> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13700: GHCi command listing possible type class instances
by GHC 21 Sep '18

21 Sep '18

#13700: GHCi command listing possible type class instances -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This is a reminder ticket, I want to be able to list possible instances, {{{ >>> :insts Product (Functor f, Functor g) => Functor (Product f g) (Applicative f, Applicative g) => Applicative (Product f g) ... >>> :insts Product Identity Functor g => Functor (Product Identity g) Applicative g => Applicative (Product Identity g) Monad g => Monad (Product Identity g) MonadFix g => MonadFix (Product Identity g) MonadZip g => MonadZip (Product Identity g) ... >>> :insts Product Identity Identity Functor (Product Identity Identity) Applicative (Product Identity Identity) Monad (Product Identity Identity) MonadFix (Product Identity Identity) MonadZip (Product Identity Identity) }}} Would be so useful for `GeneralizedNewtypeDeriving` {{{#!hs newtype Pair a = P (Product Identity Identity a) deriving (Functor, Applicative, Monad, MonadFix, MonadZip, ...) -- pattern (:#) :: a -> a -> Pair a -- pattern a1 :# a2 = P (Identity a1 `Pair` Identity a2) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13700> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11671: Allow labels starting with uppercase with OverloadedLabels
by GHC 21 Sep '18

21 Sep '18

#11671: Allow labels starting with uppercase with OverloadedLabels -------------------------------------+------------------------------------- Reporter: inaki | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.0.1-rc1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The following program {{{#!hs {-# LANGUAGE OverloadedLabels, DataKinds, FlexibleInstances, MultiParamTypeClasses #-} import GHC.OverloadedLabels instance IsLabel "Three" Int where fromLabel _ = 3 test :: Int test = #Three main :: IO () main = print test }}} fails to compile in ghc 8.0 with a parse error (while it works as expected if we replace "Three" -> "three"). This may be a conscious design decision, but if not I figured I would ask if it would be possible to allow such labels starting with uppercase letters. I run into this when working on adding support for OverloadedLabels to the gobject-introspection bindings (autogenerated bindings for gtk, etc.), where it would be natural in a few places to write overloaded labels starting with a capital letter. Not hugely important, but sometimes aesthetically more pleasing (imho), and I am not aware of a good reason to forbid them. Perhaps there is one? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11671> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13233: typePrimRep panic while compiling GHC with profiling
by GHC 20 Sep '18

20 Sep '18

#13233: typePrimRep panic while compiling GHC with profiling -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I am seeing this panic while compiling GHC stage2, {{{ ghc-stage1: panic! (the 'impossible' happened) (GHC version 8.1.20170124 for x86_64-unknown-linux): runtimeRepPrimRep typePrimRep (a :: TYPE k0) k0 Call stack: ?callStack, called at compiler/utils/Util.hs:1352:50 in ghc:Util prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1166:58 in ghc:Outputable callStackDoc, called at compiler/utils/Outputable.hs:1170:37 in ghc:Outputable pprPanic, called at compiler/simplStg/RepType.hs:360:5 in ghc:RepType Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug <<ghc: 1038844096 bytes, 158 GCs, 21564561/73278928 avg/max bytes residency (8 samples), 148M in use, 0.000 INIT (0.000 elapsed), 1.113 MUT (1.125 elapsed), 0.935 GC (0.940 elapsed) :ghc>> compiler/ghc.mk:582: recipe for target 'compiler/stage2/build/StgCmmMonad.p_o' failed }}} This appears to be due to my enabling of profiling. `build.mk` contains, {{{ BuildFlavour=prof ifneq "$(BuildFlavour)" "" include mk/flavours/$(BuildFlavour).mk endif HADDOCK_DOCS=YES compiler_HC_OPTS += -fprof-auto-exported }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13233> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11295: Figure out what LLVM passes are fruitful
by GHC 19 Sep '18

19 Sep '18

#11295: Figure out what LLVM passes are fruitful -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 (LLVM) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Builds using GHC's LLVM backend are currently substantially slower than GHC's own native code generator. There are a few possible reasons for this, 1. the cost of forking processes and serializing/parsing LLVM's intermediate representation 2. the cost of the more powerful optimizations responsible for LLVM's (hopefully) better code generation 3. the cost of redundant optimizations overlapping effort already expended by GHC Given that some architecture (e.g. ARM) are only supported by LLVM and therefore suffer considerably at the hand of our slow builds, we should try to reduce # -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11295> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12100: GHC 8.0.1 build segmentation fault in haddock
by GHC 19 Sep '18

19 Sep '18

#12100: GHC 8.0.1 build segmentation fault in haddock -------------------------------------+------------------------------------- Reporter: ilovezfs | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: MacOS X Architecture: | Type of failure: Building GHC Unknown/Multiple | failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Skylake iMac OS X 10.11.5. Xcode 7.3.1. march=native. This happens each time I attempt to build 8.0.1. The release candidates were not affected: {{{ "inplace/bin/ghc-stage2" -hisuf dyn_hi -osuf dyn_o -hcsuf dyn_hc -fPIC -dynamic -H32m -O -Wall -hide-all-packages -i -iutils/haddock/driver -iutils/haddock/haddock-api/src -iutils/haddock/haddock- library/vendor/attoparsec-0.12.1.1 -iutils/haddock/haddock-library/src -iutils/haddock/dist/build -iutils/haddock/dist/build/autogen -Iutils/haddock/dist/build -Iutils/haddock/dist/build/autogen -optP- DIN_GHC_TREE -optP-include -optPutils/haddock/dist/build/autogen/cabal_macros.h -package-id Cabal-1.24.0.0 -package-id array-0.5.1.1 -package-id base-4.9.0.0 -package-id bytestring-0.10.8.1 -package-id containers-0.5.7.1 -package-id deepseq-1.4.2.0 -package-id directory-1.2.6.2 -package-id filepath-1.4.1.0 -package-id ghc-8.0.1 -package-id ghc-boot-8.0.1 -package-id transformers-0.5.2.0 -package-id xhtml-3000.2.1 -funbox-strict-fields -Wall -fwarn-tabs -O2 -threaded -XHaskell2010 -no-user-package-db -rtsopts -Wno-unused-imports -Wno-deprecations -Wnoncanonical-monad- instances -odir utils/haddock/dist/build -hidir utils/haddock/dist/build -stubdir utils/haddock/dist/build -c utils/haddock/haddock- library/src/Documentation/Haddock/Types.hs -o utils/haddock/dist/build/Documentation/Haddock/Types.dyn_o "inplace/bin/ghc-stage2" -hisuf dyn_hi -osuf dyn_o -hcsuf dyn_hc -fPIC -dynamic -H32m -O -Wall -hide-all-packages -i -iutils/haddock/driver -iutils/haddock/haddock-api/src -iutils/haddock/haddock- library/vendor/attoparsec-0.12.1.1 -iutils/haddock/haddock-library/src -iutils/haddock/dist/build -iutils/haddock/dist/build/autogen -Iutils/haddock/dist/build -Iutils/haddock/dist/build/autogen -optP- DIN_GHC_TREE -optP-include -optPutils/haddock/dist/build/autogen/cabal_macros.h -package-id Cabal-1.24.0.0 -package-id array-0.5.1.1 -package-id base-4.9.0.0 -package-id bytestring-0.10.8.1 -package-id containers-0.5.7.1 -package-id deepseq-1.4.2.0 -package-id directory-1.2.6.2 -package-id filepath-1.4.1.0 -package-id ghc-8.0.1 -package-id ghc-boot-8.0.1 -package-id transformers-0.5.2.0 -package-id xhtml-3000.2.1 -funbox-strict-fields -Wall -fwarn-tabs -O2 -threaded -XHaskell2010 -no-user-package-db -rtsopts -Wno-unused-imports -Wno-deprecations -Wnoncanonical-monad- instances -odir utils/haddock/dist/build -hidir utils/haddock/dist/build -stubdir utils/haddock/dist/build -c utils/haddock/dist/build/autogen/Paths_haddock.hs -o utils/haddock/dist/build/Paths_haddock.dyn_o "inplace/bin/ghc-stage2" -hisuf dyn_hi -osuf dyn_o -hcsuf dyn_hc -fPIC -dynamic -H32m -O -Wall -hide-all-packages -i -iutils/haddock/driver -iutils/haddock/haddock-api/src -iutils/haddock/haddock- library/vendor/attoparsec-0.12.1.1 -iutils/haddock/haddock-library/src -iutils/haddock/dist/build -iutils/haddock/dist/build/autogen -Iutils/haddock/dist/build -Iutils/haddock/dist/build/autogen -optP- DIN_GHC_TREE -optP-include -optPutils/haddock/dist/build/autogen/cabal_macros.h -package-id Cabal-1.24.0.0 -package-id array-0.5.1.1 -package-id base-4.9.0.0 -package-id bytestring-0.10.8.1 -package-id containers-0.5.7.1 -package-id deepseq-1.4.2.0 -package-id directory-1.2.6.2 -package-id filepath-1.4.1.0 -package-id ghc-8.0.1 -package-id ghc-boot-8.0.1 -package-id transformers-0.5.2.0 -package-id xhtml-3000.2.1 -funbox-strict-fields -Wall -fwarn-tabs -O2 -threaded -XHaskell2010 -no-user-package-db -rtsopts -Wno-unused-imports -Wno-deprecations -Wnoncanonical-monad- instances -odir utils/haddock/dist/build -hidir utils/haddock/dist/build -stubdir utils/haddock/dist/build -c utils/haddock/haddock- library/src/Documentation/Haddock/Utf8.hs -o utils/haddock/dist/build/Documentation/Haddock/Utf8.dyn_o make[1]: *** [utils/haddock/dist/build/Haddock/Backends/Hyperlinker/Types.dyn_o] Segmentation fault: 11 make[1]: *** Waiting for unfinished jobs.... make[1]: *** [utils/haddock/dist/build/Documentation/Haddock/Types.dyn_o] Segmentation fault: 11 make[1]: *** [utils/haddock/dist/build/Haddock/GhcUtils.dyn_o] Segmentation fault: 11 make[1]: *** [utils/haddock/dist/build/Paths_haddock.dyn_o] Segmentation fault: 11 make[1]: *** [utils/haddock/dist/build/ResponseFile.dyn_o] Segmentation fault: 11 make: *** [all] Error 2 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12100> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13279: Check known-key lists
by GHC 19 Sep '18

19 Sep '18

#13279: Check known-key lists -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 8.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | performance bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I noticed that `fmap` (for example) has a known key {{{#!hs fmapName = varQual gHC_BASE (fsLit "fmap") fmapClassOpKey fmapClassOpKey = mkPreludeMiscIdUnique 173 }}} but its `RdrName` doesn't refer to it. {{{#!hs fmap_RDR = varQual_RDR gHC_BASE (fsLit "fmap") }}} Is there a reason for this? If not, it seems likely that we could get a bit of a speed-up by using `fmapName` here. We may also consider making `liftA2` known-key for `Traversable` deriving. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13279> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11284: Lambda-lifting fails in simple Text example
by GHC 18 Sep '18

18 Sep '18

#11284: Lambda-lifting fails in simple Text example -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Consider the example, {{{#!hs import Data.Char (isSpace) import Data.List (foldl') import GHC.Exts (build) import qualified Data.Text as T longestWord :: T.Text -> Int longestWord t = foldl' max 0 $ map T.length $ fusedWords t fusedWords :: T.Text -> [T.Text] fusedWords t0 = build $ \cons nil -> let go !t | T.null t = nil | otherwise = let (w, rest) = T.span (not . isSpace) t in cons w (go $ T.dropWhile isSpace rest) in go t0 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11284> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10859: Generated Eq instance associates && wrongly
by GHC 18 Sep '18

18 Sep '18

#10859: Generated Eq instance associates && wrongly -------------------------------------+------------------------------------- Reporter: nomeata | Owner: simonpj Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.10.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #10858 Differential Revisions: | -------------------------------------+------------------------------------- Currently, we derive this code for `(==)`: {{{ (==) (ImportDecl a1_acXi a2_acXj a3_acXk a4_acXl a5_acXm a6_acXn a7_acXo a8_acXp) (ImportDecl b1_acXq b2_acXr b3_acXs b4_acXt b5_acXu b6_acXv b7_acXw b8_acXx) = (((((((((a1_acXi == b1_acXq)) && ((a2_acXj == b2_acXr))) && ((a3_acXk == b3_acXs))) && ((a4_acXl == b4_acXt))) && ((a5_acXm == b5_acXu))) && ((a6_acXn == b6_acXv))) && ((a7_acXo == b7_acXw))) && ((a8_acXp == b8_acXx))) }}} To me this looks wrongly associated: Since `&&` is strict in the left but lazy in the right argument, shouldn’t this be associated the other way around? The compiler might clean it up later, but why not produce it correctly right away? The culprit is this line: {{{ = foldl1 and_Expr (zipWith3Equal "nested_eq" nested_eq tys as bs) }}} and I was just about to change that ot `foldr1`, but then I did some git- archeology and found that Simon changed that deliberately from `foldr1` to `foldl1` in changeset:8de16184643ea3c2f9f30b5eaed18db6ef247760. Simon, do you still recall what you were thinking when you applied this commit ... 18½years ago? :-) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10859> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13617: Segfault in Windows GHCi involving C code compiled with -O4
by GHC 17 Sep '18

17 Sep '18

#13617: Segfault in Windows GHCi involving C code compiled with -O4 ----------------------------------------+------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 8.0.2 Keywords: | Operating System: Windows Architecture: Unknown/Multiple | Type of failure: GHCi crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ----------------------------------------+------------------------------- This is a very elusive bug that I noticed when running an `hmatrix` example under GHCi on Windows. Luckily, this example can be reduced down to a couple of `.hs` files and a single `.c` file (with no other Haskell or C dependencies). Unfortunately, I can't quite figure out a way to reproduce this bug without `cabal`, so I've put the source code at https://github.com/RyanGlScott/hmatrix-segfault. You can reproduce this bug by doing the following: {{{ $ git clone https://github.com/RyanGlScott/hmatrix-segfault $ git reset 2bfe38f964fca64dd776993c89ec59d35fb368a5 $ cd hmatrix-segfault/ $ cabal install $ runghc exe/Main.hs Access violation in generated code when reading ffffffffffffffff }}} Running `Main.hs` in GHCi crashes, whereas compiling it works: {{{ $ ghc exe/Main.hs $ ./exe/Main.exe [1,1,1,1,1,1,1,1,1,1,1,1] }}} I've reproduced this with GHC 7.10.3, 8.0.2, and 8.2.1-rc1. There are a couple of things that appear to be necessary to trigger the segfault: 1. You need to have `-O4` under `cc-options` in `hmatrix-segfault.cabal`. 2. You need to define the [https://github.com/RyanGlScott/hmatrix- segfault/blob/2bfe38f964fca64dd776993c89ec59d35fb368a5/src/Internal/Vectorized.hs#L38 FunCodeS] datatype. Removing either of these things causes the program to work again under GHCi. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13617> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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