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[GHC] #12910: Mirror mingw signature files
by GHC 11 Mar '17

11 Mar '17

#12910: Mirror mingw signature files ----------------------------------------+--------------------------------- Reporter: bgamari | Owner: bgamari Type: task | Status: new Priority: high | Milestone: 8.2.1 Component: None | Version: 8.0.1 Keywords: | Operating System: POSIX Architecture: Unknown/Multiple | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ----------------------------------------+--------------------------------- We should really provide signatures alongside the mingw binaries and sources on `ghc.haskell.org`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12910> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13068: GHC should not allow modules to define instances of abstract type classes
by GHC 11 Mar '17

11 Mar '17

#13068: GHC should not allow modules to define instances of abstract type classes -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 8.1 (Type checker) | Keywords: backpack | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC accepts Unknown/Multiple | invalid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- hs-boot files permit a type class to be given "abstractly", in which case any implementation of the type class is permissible. But it does not reject instances defined for such a class. {{{ -- A.hs-boot module A where class C a -- B.hs module B where import {-# SOURCE #-} A instance C Int where -- A.hs module A where import B class C a where f :: a -- Main.hs import A main = print (f :: Int) }}} I get this when I build with `--make`: {{{ ezyang@sabre:~$ ghc-head --make C.hs -fforce-recomp [1 of 4] Compiling A[boot] ( A.hs-boot, A.o-boot ) [2 of 4] Compiling B ( B.hs, B.o ) [3 of 4] Compiling A ( A.hs, A.o ) [4 of 4] Compiling Main ( C.hs, C.o ) Linking C ... ./B.o:(.data+0x0): undefined reference to `A_CZCC_con_info' collect2: error: ld returned 1 exit status }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13068> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13393: GHC panic: No skolem info
by GHC 11 Mar '17

11 Mar '17

#13393: GHC panic: No skolem info -------------------------------------+------------------------------------- Reporter: sheyll | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Compile-time (amd64) | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I got this GHC output: {{{ /home/sven/DEV_LBM/lbm-talk-flow/mediabus-fdk- aac/src/Data/MediaBus/Audio/FdkAac/Encoder.hs:124:8: error:ghc: panic! (the 'impossible' happened) (GHC version 8.0.2 for x86_64-unknown-linux): No skolem info: k_ataY[sk] Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} It happens when I omit a type signature. We do not have the resources right now to create a minimal test case, but I didn't want to ignore the request to file a bug report. This happens in a small project available on github, I commited the specific code and tagged the commit 'ghc-panic' and added a comment in the code. I doubt that is makes sense to paste the code here, so if anyone looks into this, please grab the code from github at: [https://github.com/lindenbaum/mediabus-fdk-aac/blob/ghc- panic/src/Data/MediaBus/Audio/FdkAac/Encoder.hs] Sorry if this bug report is not helpful. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13393> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1600: Optimisation: CPR the results of IO
by GHC 11 Mar '17

11 Mar '17

#1600: Optimisation: CPR the results of IO -------------------------------------+------------------------------------- Reporter: simonmar | Owner: (none) Type: task | Status: new Priority: lowest | Milestone: Component: Compiler | Version: 6.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: #8598 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): Akio, I've fixed that wrapper issue. What's next on this ticket? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1600#comment:68> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1600: Optimisation: CPR the results of IO
by GHC 11 Mar '17

11 Mar '17

#1600: Optimisation: CPR the results of IO -------------------------------------+------------------------------------- Reporter: simonmar | Owner: (none) Type: task | Status: new Priority: lowest | Milestone: Component: Compiler | Version: 6.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: #8598 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Simon Peyton Jones <simonpj@…>): In [changeset:"900cfdc2700ad9e8c7a12dd25bb0396e5e7651df/ghc" 900cfdc2/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="900cfdc2700ad9e8c7a12dd25bb0396e5e7651df" Do not generate a data-con wrapper for !Int# See Note [Data con wrappers and unlifted types] in MkId. We were being totally stupid! See Trac #1600 comment:66 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1600#comment:67> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13409: Data types with higher-rank kinds are pretty-printed strangely
by GHC 10 Mar '17

10 Mar '17

#13409: Data types with higher-rank kinds are pretty-printed strangely -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 (Type checker) | Keywords: TypeInType | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #13399 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- First observed in https://ghc.haskell.org/trac/ghc/ticket/13399#comment:5. If you define this: {{{#!hs data Foo :: (* -> *) -> (forall k. k -> *) }}} and type `:i Foo` into GHCi, you get this back: {{{ type role Foo phantom nominal phantom data Foo (a :: * -> *) k (c :: k) }}} This seems to imply that Foo has three visible type parameters, which isn't true at all! -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13409> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13384: Windows build thinks sqrt (-1) == -1
by GHC 10 Mar '17

10 Mar '17

#13384: Windows build thinks sqrt (-1) == -1 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Incorrect result Unknown/Multiple | at runtime Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- As of 749740f9c3cb25ee95e04a21c1ef73e1bf96afb1, {{{ $ inplace/bin/ghc-stage2 --interactive GHCi, version 8.1.20170306: http://www.haskell.org/ghc/ :? for help Prelude> sqrt (-1) :: Double -1.0 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13384> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11555: catch under unsafePerformIO breaks on -O1
by GHC 10 Mar '17

10 Mar '17

#11555: catch under unsafePerformIO breaks on -O1 -------------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1-rc2 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: -------------------------------------+------------------------------------- Discovered on xmonad-0.12 test failure. Happens on today's -HEAD and ghc-8.0.1-rc1,-rc2 Short example is (needs only base): {{{#!hs -- cat F.hs module F where import qualified Control.Exception as C import System.IO.Unsafe import qualified Data.List as L abort :: String -> a abort x = error $ "xmonad: StackSet: " ++ x prop_abort x = unsafePerformIO $ C.catch (abort "fail") (\(C.SomeException e) -> return $ "xmonad: StackSet: fail" `L.isPrefixOf` show e ) where _ = x :: Int }}} Session 1 [ok]: {{{ $ ghci F.hs GHCi, version 8.0.0.20160204: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling F ( F.hs, interpreted ) Ok, modules loaded: F. *F> prop_abort 1 True }}} Session 2 [fails]: {{{ $ ghci -O1 -fobject-code F.hs GHCi, version 8.0.0.20160204: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling F ( F.hs, F.o ) Ok, modules loaded: F. Prelude F> prop_abort 1 *** Exception: xmonad: StackSet: fail CallStack (from HasCallStack): error, called at F.hs:9:11 in main:F }}} I would expect exception to be caught on both cases. Is it unreasonable expectation in light of unsafePerformIO? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11555> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13348: Consider making throw and throwIO strict
by GHC 10 Mar '17

10 Mar '17

#13348: Consider making throw and throwIO strict -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: 8.4.1 Component: Core | Version: 8.1 Libraries | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Other Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- It's possible for code to throw an exception that itself throws an imprecise exception. Such an exception is tricky to catch. For example: {{{#!hs import Control.Exception strange = throwIO (undefined :: SomeException) `catch` \ex -> case () of _ | Just _ <- (fromException ex :: Maybe IOError) -> print "IOError" | otherwise -> print "Something else" }}} You might think that this would catch the exception and print "Something else", but in fact it does not. If others think this is as surprising as I do, perhaps we should make `throwIO` and `throw` strict, so an exception will never itself be bottom. Using {{{#!hs throwIO' !e = throwIO e }}} in the code above instead of `throwIO` allows the exception to be caught. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13348> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1409: Allow recursively dependent modules transparently (without .hs-boot or anything)
by GHC 10 Mar '17

10 Mar '17

#1409: Allow recursively dependent modules transparently (without .hs-boot or anything) -------------------------------------+------------------------------------- Reporter: Isaac Dupree | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: ⊥ Component: Compiler | Version: 6.10.2 Resolution: | Keywords: backpack Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #9256 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by mentheta): * cc: mentheta (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1409#comment:70> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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