October 2016 - ghc-tickets

[GHC] #11158: Combine exprIsTrivial and cpe_ExprIsTrivial
by GHC 25 Nov '16

25 Nov '16

#11158: Combine exprIsTrivial and cpe_ExprIsTrivial -------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | 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: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Look at `CoreUtils.exprIsTrivial` and `CorePrep.cpe_ExprIsTrivial`. They are identical! The latter has a comment saying {{{ cpe_ExprIsTrivial :: CoreExpr -> Bool -- Version that doesn't consider an scc annotation to be trivial. }}} but the code does not treat ticks any differently. So the question is: '''are they supposed to be different'''? And if not, can we just combine them? Peter W, Simon M: this is your territory. I don't understand tick stuff well enough. Simon -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11158> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12526: regression in type inference with respect to type families
by GHC 25 Nov '16

25 Nov '16

#12526: regression in type inference with respect to type families -------------------------------------+------------------------------------- Reporter: Lemming | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.2 Component: Compiler | Version: 8.1 (Type checker) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The following bug is present in ghc-8.0.1.20160725, ghc-8.0.1.20160822 (ghc-8.0.2) and ghc-8.1.20160819 (ghc-head) and was not there in ghc-8.0.1. When compiling the head version of synthesizer-llvm package from http://code.haskell.org/synthesizer/llvm/ I get the following error: {{{ src/Synthesizer/LLVM/Server/CausalPacked/Instrument.hs:296:23: error: • Couldn't match type ‘Synthesizer.Causal.Class.ProcessOf t0’ with ‘CausalP.T (SampleRate Real, ())’ Expected type: CausalP.T (SampleRate Real, ()) (Serial.T (LLVM.Value (LLVM.Vector (TypeNum.Pos Type.Data.Num.Decimal.Digit.Dec4 TypeNum.EndDesc) Float)), (Serial.Value (TypeNum.Pos Type.Data.Num.Decimal.Digit.Dec4 TypeNum.EndDesc) Real, VectorValue)) (Serial.T (LLVM.Value (LLVM.Vector (TypeNum.Pos Type.Data.Num.Decimal.Digit.Dec4 TypeNum.EndDesc) Float))) Actual type: Synthesizer.Causal.Class.ProcessOf t0 (Serial.T (LLVM.Value (LLVM.Vector (TypeNum.Pos Type.Data.Num.Decimal.Digit.Dec4 TypeNum.EndDesc) Float)), (Serial.Value (TypeNum.Pos Type.Data.Num.Decimal.Digit.Dec4 TypeNum.EndDesc) Float, Serial.Value (TypeNum.Pos Type.Data.Num.Decimal.Digit.Dec4 TypeNum.EndDesc) Float)) (Serial.T (LLVM.Value (LLVM.Vector (TypeNum.Pos Type.Data.Num.Decimal.Digit.Dec4 TypeNum.EndDesc) Float))) The type variable ‘t0’ is ambiguous • In the first argument of ‘($&)’, namely ‘osci’ In the second argument of ‘liftA2’, namely ‘(osci $& shapeCtrl &|& (expo &|& fmap Stereo.left freqs))’ In the expression: liftA2 Stereo.cons (osci $& shapeCtrl &|& (expo &|& fmap Stereo.left freqs)) (osci $& shapeCtrl &|& (negate expo &|& fmap Stereo.right freqs)) • Relevant bindings include osci :: Synthesizer.Causal.Class.ProcessOf t0 (Serial.T (LLVM.Value (LLVM.Vector (TypeNum.Pos Type.Data.Num.Decimal.Digit.Dec4 TypeNum.EndDesc) Float)), (Serial.Value (TypeNum.Pos Type.Data.Num.Decimal.Digit.Dec4 TypeNum.EndDesc) Float, Serial.Value (TypeNum.Pos Type.Data.Num.Decimal.Digit.Dec4 TypeNum.EndDesc) Float)) (Serial.T (LLVM.Value (LLVM.Vector (TypeNum.Pos Type.Data.Num.Decimal.Digit.Dec4 TypeNum.EndDesc) Float))) (bound at src/Synthesizer/LLVM/Server/CausalPacked/Instrument.hs:294:19) }}} The type for `t0` should be known and then the type checker should be able to check that `ProcessOf t0` equals `CausalP.T`. It did so in earlier versions but now fails on that part. I still have to reduce that example, but for now I want to alert you that there seems to be a regression in the type inference. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12526> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12538: Incorrect uses of overlapping instances and data families sends GHC into loop
by GHC 25 Nov '16

25 Nov '16

#12538: Incorrect uses of overlapping instances and data families sends GHC into loop -------------------------------------+------------------------------------- Reporter: pkmx | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 (Type checker) | 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: -------------------------------------+------------------------------------- Sorry for the lack of descriptive title, as I can't nail down the source of this specific bug. This is the minimal example to trigger the loop: {{{#!hs {-# LANGUAGE CPP #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE FunctionalDependencies #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE TypeApplications #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE UndecidableInstances #-} module Main where import GHC.TypeLits import GHC.Types data Tagged t a = Tagged a type family Tag a where Tag (Tagged t a) = Tagged t a Tag a = Tagged Int a class (r ~ Tag a) => TagImpl a r | a -> r where tag :: a -> r instance {-# OVERLAPPING #-} (r ~ Tag (Tagged t a)) => TagImpl (Tagged t a) r where tag = id #ifdef WRONG instance {-# OVERLAPPING #-} (r ~ Tagged t a, r ~ Tag a) => TagImpl a r where #else instance {-# OVERLAPPING #-} (r ~ Tagged Int a, r ~ Tag a) => TagImpl a r where #endif tag = Tagged @Int data family DF x data instance DF (Tagged t a) = DF (Tagged t a) class ToDF a b | a -> b where df :: a -> b #ifdef WRONG instance (TagImpl a a', b ~ DF a') => ToDF a b where #else instance (TagImpl a (Tagged t a'), b ~ DF (Tagged t a')) => ToDF a b where #endif df = DF . tag main :: IO () main = pure () }}} When compiled with `-DWRONG`, it causes GHC (both 8.0.1 and HEAD@20160823) to loop: {{{ $ ghc --version && ghc -fno-code Main.hs -DWRONG The Glorious Glasgow Haskell Compilation System, version 8.1.20160823 [1 of 1] Compiling Main ( Main.hs, nothing ) (loops indefinitely...) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12538> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11575: Program crashes only when compiled via LLVM
by GHC 23 Nov '16

23 Nov '16

#11575: Program crashes only when compiled via LLVM --------------------------------------+---------------------------------- Reporter: Guest00000 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: None | Version: 7.10.3 Keywords: llvm | Operating System: Windows Architecture: x86_64 (amd64) | Type of failure: Runtime crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------------+---------------------------------- `llvm-test.hs`: {{{#!hs import System.IO import Foreign.Storable import Foreign.Marshal.Alloc import Data.Word main = do hSetBuffering stdout NoBuffering test 1000 test 5000 where test n = do allocaBytes (n * 4) $ \p -> do sequence_ [ pokeByteOff p (i * 4) (0x12345678 :: Word32) | i <- [ 0 .. n - 1 ] ] putStrLn $ show n ++ " fine" }}} ---- Cygwin shell: {{{ user@pc ~ $ ghc llvm-test.hs && ./llvm-test.exe [1 of 1] Compiling Main ( llvm-test.hs, llvm-test.o ) Linking llvm-test.exe ... 1000 fine 5000 fine user@pc ~ $ touch llvm-test.hs user@pc ~ $ ghc llvm-test.hs -fllvm && ./llvm-test.exe [1 of 1] Compiling Main ( llvm-test.hs, llvm-test.o ) Linking llvm-test.exe ... 1000 fine Segmentation fault }}} ---- {{{ <erikd> `Guest00000: try adding -O2 to the compiler command line. <`Guest00000> erikd: it now segfaults even before printing "1000 fine" <`Guest00000> wait, one time it printed one character "1" before crashing }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11575> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8300: split-objs doesn't split on LLVM
by GHC 22 Nov '16

22 Nov '16

#8300: split-objs doesn't split on LLVM ------------------------------------+------------------------------------- Reporter: rwbarton | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler (LLVM) | Version: 7.7 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- `-split-objs` is allowed with `-fllvm`, but it doesn't really do anything. E.g. in my perf-llvm build I have a `libHSbase-4.7.0.0.a` with `Applicative__1.o`, `Arrow__1.o` etc. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8300> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12697: Improve output of pattern synonym info
by GHC 21 Nov '16

21 Nov '16

#12697: Improve output of pattern synonym info -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple PatternSynonyms | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs import GHC.Prim import Data.Kind data TypeRep :: forall k. k -> Type where TI :: TypeRep Int TB :: TypeRep Bool TL :: TypeRep [] TA :: TypeRep f -> TypeRep x -> TypeRep (f x) data (a::k1) :~~: (b::k2) where HRefl :: a :~~: a deriving instance Show (a :~~: b) eqTT :: TypeRep (a::k1) -> TypeRep (b::k2) -> Maybe (a :~~: b) eqTT TI TI = Just HRefl eqTT TB TB = Just HRefl eqTT TL TL = Just HRefl pattern IsList <- (eqTT TL -> Just HRefl) where IsList = TL }}} What is the type of `IsList`? The result of `:type` is only accurate when used as an expression (`IsList :: TypeRep []`) and the result of `:info` is uses `~#` {{{ >>> :info IsList pattern IsList :: forall k2 (b :: k2). () => ((* -> *) ~# k2, [] ~# b) => TypeRep b }}} which won't parse (`parse error on input ‘~#’`). {{{#!hs -- t9R4.hs:20:67: error: … -- • Expected kind ‘* -> *’, but ‘b’ has kind ‘k2’ -- • In the second argument of ‘~’, namely ‘b’ -- Compilation failed. pattern IsList :: forall k2 (b :: k2). () => ((* -> *) ~ k2, [] ~ b) => TypeRep b pattern IsList <- (eqTT TL -> Just HRefl) where IsList = TL }}} The user may try to use `~` but we need [https://hackage.haskell.org/package/ghc-prim-0.5.0.0/docs/GHC- Types.html#t:-126--126- heterogeneous equality from GHC.Types] (`~~`) {{{#!hs pattern IsList :: forall k2 (b :: k2). () => ((* -> *) ~ k2, [] ~~ b) => TypeRep b }}} and in the end, we only need {{{#!hs pattern List :: () => [] ~~ b => T b }}} `:info` should show something closer to that! Copy-pasting should work -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12697> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12024: GHC leaks GHC.Prim.~# into type
by GHC 21 Nov '16

21 Nov '16

#12024: GHC leaks GHC.Prim.~# into type -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 (Type checker) | 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: -------------------------------------+------------------------------------- {{{#!hs data A a where X :: A [xxx] pattern X' = X }}} the inferred type of which is {{{ >>> :info X' pattern X' :: () => t GHC.Prim.~# [xxx] => A t }}} Casts use unlifted equality as I understand it, but lifted would present a nicer UI: {{{#!hs pattern X' :: () => t ~> [xxx] => A t pattern X' = X }}} In my own code this means I get the following monster {{{#!hs pattern MkArr :: () => (GetTy a, GetTy b, GetTy t, a GHC.Prim.~# 'Sca ('Number 'I32), b GHC.Prim.~# 'Sca a1, t GHC.Prim.~# 'Arr a1, GetSca a1) => Exp a -> Id -> Exp b -> Exp t }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12024> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12757: Compiled program segfaults at -O1
by GHC 20 Nov '16

20 Nov '16

#12757: Compiled program segfaults at -O1 -------------------------------------+------------------------------------- Reporter: hvr | Owner: Type: bug | Status: new Priority: highest | Milestone: 8.0.2 Component: Compiler | Version: 8.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Runtime crash Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This affects GHC 8.0.2dev (d84a824cebe94711528727bcb587bfc369ec36a2) as well as GHC HEAD (c23dc6164d54eacc654516b885104dc8b7678f16) The following program results in a segfault when compiled at -O1 or more: {{{#!hs {-# LANGUAGE OverloadedStrings #-} module Main (main) where import Data.ByteString (ByteString) import qualified Data.ByteString as B answers :: [ByteString] answers = map (B.filter (/= 0x20)) [ "e3b0c442 98fc1c14 9afbf4c8 996fb924 27ae41e4 649b934c a495991b 7852b855" , "d7a8fbb3 07d78094 69ca9abc b0082e4f 8d5651e4 6d3cdb76 2d02d0bf 37c9e592" , "e4c4d8f3 bf76b692 de791a17 3e053211 50f7a345 b46484fe 427f6acc 7ecc81be" , "ba7816bf 8f01cfea 414140de 5dae2223 b00361a3 96177a9c b410ff61 f20015ad" , "248d6a61 d20638b8 e5c02693 0c3e6039 a33ce459 64ff2167 f6ecedd4 19db06c1" , "cf5b16a7 78af8380 036ce59e 7b049237 0b249b11 e8f07a51 afac4503 7afee9d1" , "cdc76e5c 9914fb92 81a1c7e2 84d73e67 f1809a48 a497200e 046d39cc c7112cd0" ] x, y :: ByteString x = "e3b0c442 98fc1c14 9afbf4c8 996fb924 27ae41e4 649b934c a495991b 7852b855" y = B.filter (/= 0x20) x main :: IO () main = do print (seq x ()) print (seq y ()) print (length answers) print (seq (head answers) ()) -- segfault! }}} {{{ $ ghc-8.0.2 -fforce-recomp --make -O1 bug.hs && ./bug [1 of 1] Compiling Main ( bug.hs, bug.o ) Linking bug ... () () 7 Segmentation fault }}} {{{ $ ghc-8.0.2 -fforce-recomp --make -O0 bug.hs && ./bug [1 of 1] Compiling Main ( bug.hs, bug.o ) Linking bug ... () () 7 () }}} I haven't yet investigated why this happens. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12757> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12675: Simplifier ticks exhausted
by GHC 19 Nov '16

19 Nov '16

#12675: Simplifier ticks exhausted --------------------------------------+--------------------------------- Reporter: davean | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------------+--------------------------------- Works with "-fsimpl-tick-factor=102". Code is: ... import qualified Data.Vector.Unboxed as UV import qualified Data.Vector.Generic as VG import qualified Data.Vector.Algorithms.Tim as Tim ... ∀ v alphabet. (VG.Vector v alphabet, Ord (v alphabet)) ⇒ v alphabet → SA ... SA ∘ VG.modify (Tim.sortBy (lexSuffixCmp st)) ∘ UV.enumFromN 0 $ VG.length st+1 ... -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12675> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12079: seg fault while using gtk
by GHC 19 Nov '16

19 Nov '16

#12079: seg fault while using gtk --------------------------------------+---------------------------------- Reporter: doofin | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 Keywords: | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: Runtime crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------------+---------------------------------- {{{#!hs {-# LANGUAGE OverloadedStrings #-} module Main where import Graphics.UI.Gtk import System.Glib.Signals import Graphics.UI.Gtk.SourceView import Graphics.UI.Gtk.SourceView.SourceGutter import Graphics.UI.Gtk.SourceView.SourceCompletion import Graphics.UI.Gtk.SourceView.SourceMark import Graphics.UI.Gtk.SourceView.SourceBuffer import Graphics.UI.Gtk.Multiline.TextBuffer import Graphics.UI.Gtk.Gdk.EventM import Control.Monad.Trans import System.FSNotify import System.Environment import Control.Concurrent (threadDelay) import Control.Monad (forever) import qualified Data.Text as T import qualified Data.Text.IO as T import Data.Tuple import Data.Tuple.HT import Control.Concurrent main=do args<-getArgs print args let filename=head args txt<-T.readFile filename gtk txt $ \srcbf->do notify $ \evt -> case evt of Modified fp _->if (T.unpack $ Prelude.last $ T.splitOn "/" $ T.pack fp)==filename then do txtnew<-T.readFile $ head args postGUIAsync $ textBufferSetText srcbf (txtnew::T.Text) else return () _->return () return () notify action=withManager $ \mgr-> do --mgr<-startManager watchTree mgr -- manager "." -- directory to watch (const True) -- predicate $ \evt->do print evt-- action action evt forever $ threadDelay 1000000 -- sleep forever (until interrupted) gtk inittext act= do initGUI window <- windowNew windowSetDefaultSize window 900 600 windowSetPosition window WinPosCenter srcbf<-sourceBufferNew Nothing sourceView <- sourceViewNewWithBuffer srcbf scrolledWindow <- scrolledWindowNew Nothing Nothing sourceViewSetShowLineNumbers sourceView True textViewSetWrapMode sourceView WrapWord textBufferInsertAtCursor srcbf ("fdsf"::String) textBufferSetText srcbf inittext scrolledWindow `containerAdd` sourceView window `containerAdd` scrolledWindow widgetShowAll window on sourceView keyPressEvent $ do kl<-eventKeyName liftIO $ putStr $ show $ kl liftIO $ mapM_ (\(x,y)->if x==kl then textBufferInsertAtCursor srcbf (y::String) else return ()) pairs return False on window deleteEvent $ liftIO mainQuit >> return False connectGeneric "notify::cursor-position" False srcbf $ do print "adsfd" forkIO $ do act srcbf --onDestroy window mainQuit mainGUI pairs=[("parenleft",")"),("[","]")] }}} the program runs ok before adding the line {{{#!hs connectGeneric "notify::cursor-position" False srcbf $ do print "adsfd" }}} then i run ghc thisfile.hs -debug gdb thisfile run somefile move the cursor inside the textview,then seg fault happened bt {{{ result: Program received signal SIGSEGV, Segmentation fault. 0x00007fffeea0f4f0 in ?? () (gdb) bt #0 0x00007fffeea0f4f0 in ?? () #1 0x00000000000002f5 in ?? () #2 0x0000000000000309 in ?? () #3 0x00007fffffff44f8 in ?? () #4 0x00007fffffff4458 in ?? () #5 0x00007fff04fe0101 in ?? () #6 0x0000000000000113 in ?? () #7 0x00000000000002e5 in ?? () #8 0x0000000001db00ac in ?? () #9 0x00007fffeea13a21 in ?? () #10 0x00007fffeeaf5010 in ?? () #11 0x0000000000a8d709 in base_GHCziIOziFD_zdfBufferedIOFD2_closure () #12 0x00007fffeea07942 in ?? () #13 0x0000000000a8593a in base_GHCziIOziBuffer_WriteBuffer_closure () #14 0x0000000000000800 in ?? () #15 0x0000000000000000 in ?? () }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12079> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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