January 2015 - ghc-tickets

[GHC] #9056: --make paths are not deduplicated
by GHC 19 Apr '15

19 Apr '15

#9056: --make paths are not deduplicated -------------------------+------------------------------------------------- Reporter: | Owner: evincarofautumn | Status: new Type: bug | Milestone: Priority: | Version: 7.8.2 normal | Operating System: Unknown/Multiple Component: | Type of failure: Incorrect warning at Compiler | compile-time Keywords: | Test Case: Architecture: | Blocking: Unknown/Multiple | Difficulty: | Unknown | Blocked By: | Related Tickets: | -------------------------+------------------------------------------------- I had a build script with an accidental duplicate dependency, which caused GHC to be run like so: {{{ ghc --make Main.hs Main.hs }}} This results in a spurious error from `GhcMake.checkDuplicates`: {{{ <no location info>: module ‘main:Main’ is defined in multiple files: Main.hs Main.hs }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9056> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10021: Add "Error:" prefix for error-messages
by GHC 19 Apr '15

19 Apr '15

#10021: Add "Error:" prefix for error-messages -------------------------------------+------------------------------------- Reporter: k-bx | Owner: Type: feature | Status: new request | Milestone: 7.12.1 Priority: normal | Version: 7.8.4 Component: Compiler | Operating System: Unknown/Multiple Keywords: | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Similar to what we have for "Warning:". E.g., we have: {{{ ➜ cat test.hs main = putStrLn "Hello!" ➜ ghc --make -fforce-recomp -Wall ./test.hs [1 of 1] Compiling Main ( test.hs, test.o ) test.hs:1:1: Warning: Top-level binding with no type signature: main :: IO () Linking test ... ➜ cat test2.hs main = foo ➜ ghc --make -fforce-recomp -Wall ./test2.hs [1 of 1] Compiling Main ( test2.hs, test2.o ) test2.hs:1:8: Not in scope: ‘foo’ }}} And I propose having: {{{ ➜ cat test2.hs main = foo ➜ ghc --make -fforce-recomp -Wall ./test2.hs [1 of 1] Compiling Main ( test2.hs, test2.o ) test2.hs:1:8: Error: Not in scope: ‘foo’ }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10021> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9809: Overwhelming the TimerManager
by GHC 17 Apr '15

17 Apr '15

#9809: Overwhelming the TimerManager -------------------------------------+------------------------------------- Reporter: fryguybob | Owner: simonmar Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 7.9 Keywords: | Operating System: Linux Architecture: Unknown/Multiple | Type of failure: Runtime Difficulty: Unknown | performance bug Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- I was talking on IRC with davean about an issue that potentially could have been related to STM (I don't think it is at all after investigating) and I reduced the issue to the following program: {{{#!hs -- Main.hs module Main where import Control.Monad import Control.Concurrent import Control.Concurrent.STM import System.Environment main :: IO () main = do as <- getArgs case as of ["-f"] -> replicateM_ 100000 . void . forkIO . void $ registerDelay 10 _ -> replicateM_ 100000 . void $ registerDelay 10 threadDelay 1000 }}} This ends up registering a lot of events with the TimerManager. With the "-f" flag it does so from many threads and when run that way it appears to eventually overwhelm the TimerManager and causing over 350 MB total memory in use. {{{ $ ghc --version The Glorious Glasgow Haskell Compilation System, version 7.9.20141115 $ ghc -O2 -threaded -debug Main.hs -o Main-head ... $ ./Main-head -f +RTS -s 3,566,966,936 bytes allocated in the heap 4,200,021,784 bytes copied during GC 118,273,720 bytes maximum residency (96 sample(s)) 12,649,480 bytes maximum slop 354 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 6350 colls, 0 par 2.430s 2.434s 0.0004s 0.0073s Gen 1 96 colls, 0 par 7.438s 7.441s 0.0775s 0.2526s TASKS: 4 (1 bound, 3 peak workers (3 total), using -N1) SPARKS: 0 (0 converted, 0 overflowed, 0 dud, 0 GC'd, 0 fizzled) INIT time 0.002s ( 0.002s elapsed) MUT time 0.461s ( 0.460s elapsed) GC time 9.869s ( 9.875s elapsed) EXIT time 0.003s ( 0.003s elapsed) Total time 10.336s ( 10.340s elapsed) Alloc rate 7,741,472,461 bytes per MUT second Productivity 4.5% of total user, 4.5% of total elapsed gc_alloc_block_sync: 0 whitehole_spin: 0 gen[0].sync: 0 gen[1].sync: 0 }}} Running without forking many threads and the total memory in use stays low (3 MB). {{{ 154,305,648 bytes allocated in the heap 16,922,272 bytes copied during GC 1,378,608 bytes maximum residency (3 sample(s)) 28,520 bytes maximum slop 3 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 298 colls, 0 par 0.056s 0.056s 0.0002s 0.0015s Gen 1 3 colls, 0 par 0.005s 0.005s 0.0017s 0.0047s TASKS: 4 (1 bound, 3 peak workers (3 total), using -N1) SPARKS: 0 (0 converted, 0 overflowed, 0 dud, 0 GC'd, 0 fizzled) INIT time 0.001s ( 0.001s elapsed) MUT time 0.148s ( 0.148s elapsed) GC time 0.061s ( 0.061s elapsed) EXIT time 0.000s ( 0.000s elapsed) Total time 0.211s ( 0.210s elapsed) Alloc rate 1,042,557,595 bytes per MUT second Productivity 70.8% of total user, 71.2% of total elapsed gc_alloc_block_sync: 0 whitehole_spin: 0 gen[0].sync: 0 gen[1].sync: 0 }}} Using 7.6.3, things don't get out of hand, also with 3 MB total memory use. {{{ $ ./Main-7.6.3 -f +RTS -s 213,519,392 bytes allocated in the heap 116,111,712 bytes copied during GC 505,080 bytes maximum residency (11 sample(s)) 113,032 bytes maximum slop 3 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 403 colls, 0 par 0.33s 0.33s 0.0008s 0.0028s Gen 1 11 colls, 0 par 0.01s 0.01s 0.0011s 0.0019s TASKS: 3 (1 bound, 2 peak workers (2 total), using -N1) SPARKS: 0 (0 converted, 0 overflowed, 0 dud, 0 GC'd, 0 fizzled) INIT time 0.00s ( 0.00s elapsed) MUT time 1.99s ( 1.50s elapsed) GC time 0.34s ( 0.34s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 2.33s ( 1.84s elapsed) Alloc rate 107,426,859 bytes per MUT second Productivity 85.5% of total user, 108.1% of total elapsed gc_alloc_block_sync: 0 whitehole_spin: 0 gen[0].sync: 0 gen[1].sync: 0 }}} I looked for causes and eliminated any `STM` interactions causing problems (`STM` shows up in the `Unique` values and in creating a `TVar` for the registered delay) but did discover that the `emTimeouts` queue gets very large at some point when executing with "-f". If I print the size of `expired` on this line: https://github.com/ghc/ghc/blob/021b7978d14799bae779907faf7490cfd21b3f46/li… I end up seeing somewhere from 4 to 20 events for a while then eventually it jumps up to 80000 or so. Perhaps davean can chime in about the particular use case that he has that I reduced to this simple program for a more real world use. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9809> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9180: New magic function `staticError`
by GHC 16 Apr '15

16 Apr '15

#9180: New magic function `staticError` ------------------------------------+------------------------------------- Reporter: nomeata | Owner: nomeata Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- While playing games with `RULES`, I had the need for a way to tell the compiler “please spit out an error message”, in my case if list fusion fails where the user explicitly requested for it. Currently I put an `error "List did not fuse"` in the code using a `RULE`, but what I’d really like to do is to put in a `staticError "List did not fuse"` that, if appearing in Core (say, after the final simplification) causes GHC to abort and print this message. (I’m tempted to use type level strings somehow to make sure that the parameter to `staticError` is not present at the value level, and also that the string is easier to obtain. I’ll see.) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9180> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8391: FunDeps coverage condition check failure with PolyKinds
by GHC 15 Apr '15

15 Apr '15

#8391: FunDeps coverage condition check failure with PolyKinds ----------------------------+---------------------------------------------- Reporter: sbarclay | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.7 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC rejects valid program Unknown/Multiple | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: #8356 | ----------------------------+---------------------------------------------- The following code: {{{ #!haskell {-# LANGUAGE FunctionalDependencies, FlexibleInstances, UndecidableInstances, TypeFamilies, PolyKinds #-} module FunDepsIssue where type Foo a = a class Foo a ~ b => Bar a b | a -> b instance Foo a ~ b => Bar a b }}} results in: {{{ Illegal instance declaration for ‛Bar k a b’ Multiple uses of this instance may be inconsistent with the functional dependencies of the class. In the instance declaration for ‛Bar a b’ }}} This appears to be a regression from 7.6.3, where it compiles OK. The same error occurs when the type synonym is replaced with a type family (which is the case I was originally interested in) or a type constructor like `Data.Proxy`, as long as it's poly-kinded it seems. So the following cases also fail to compile: {{{ #!haskell type family Foo (a :: k) :: * type family Foo (a :: *) :: k type family Foo (a :: k) :: k type family Foo (a :: k) :: k' }}} Looking through the source code, I think that the issue is that the coverage condition check doesn't close over kind variables, when it compares the vars on each side of the functional dependency. But `Foo a` has a hidden kind variable, so the l.h. varset `{a}` is insufficient to fix `b` using `Foo a ~ b`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8391> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8276: Building Haddock documentation panics with perf build on x86_64 Linux
by GHC 14 Apr '15

14 Apr '15

#8276: Building Haddock documentation panics with perf build on x86_64 Linux ----------------------------------+--------------------------------------- Reporter: jstolarek | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Documentation | Version: 7.7 Keywords: | Operating System: Unknown/Multiple Architecture: x86_64 (amd64) | Type of failure: Compile-time crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+--------------------------------------- After setting `BuildFlavor = perf` in `build.mk` compilation ends with a panic: {{{ "/home/luite/buildtest/ghc-clean-buildtest/ghc/inplace/bin/haddock" --odir="libraries/ghc-prim/dist-install/doc/html/ghc-prim" --no-tmp-comp- dir --dump-interface=libraries/ghc-prim/dist-install/doc/html/ghc-prim /ghc-prim.haddock --html --hoogle --title="ghc-prim-0.3.1.0: GHC primitives" --prologue="libraries/ghc-prim/dist-install/haddock- prologue.txt" --optghc=-hisuf --optghc=dyn_hi --optghc=-osuf --optghc=dyn_o --optghc=-hcsuf --optghc=dyn_hc --optghc=-fPIC --optghc=-dynamic --optghc=-H32m --optghc=-O --optghc=-package-name --optghc=ghc-prim-0.3.1.0 --optghc=-hide-all-packages --optghc=-i --optghc=-ilibraries/ghc-prim/. --optghc=-ilibraries/ghc-prim/dist- install/build --optghc=-ilibraries/ghc-prim/dist-install/build/autogen --optghc=-Ilibraries/ghc-prim/dist-install/build --optghc=-Ilibraries/ghc- prim/dist-install/build/autogen --optghc=-Ilibraries/ghc-prim/. --optghc =-optP-include --optghc=-optPlibraries/ghc-prim/dist- install/build/autogen/cabal_macros.h --optghc=-package --optghc=rts-1.0 --optghc=-package-name --optghc=ghc-prim --optghc=-XHaskell98 --optghc=-XCPP --optghc=-XMagicHash --optghc=-XForeignFunctionInterface --optghc=-XUnliftedFFITypes --optghc=-XUnboxedTuples --optghc=-XEmptyDataDecls --optghc=-XNoImplicitPrelude --optghc=-O2 --optghc=-no-user-package-db --optghc=-rtsopts --optghc=-odir --optghc=libraries/ghc-prim/dist-install/build --optghc=-hidir --optghc=libraries/ghc-prim/dist-install/build --optghc=-stubdir --optghc=libraries/ghc-prim/dist-install/build --source- module=src/%{MODULE/./-}.html --source- entity=src/%{MODULE/./-}.html#%{NAME} libraries/ghc- prim/./GHC/Classes.hs libraries/ghc-prim/./GHC/CString.hs libraries/ghc- prim/./GHC/Debug.hs libraries/ghc-prim/./GHC/Magic.hs libraries/ghc-prim /dist-install/build/GHC/PrimopWrappers.hs libraries/ghc- prim/./GHC/PrimWrappers.hs libraries/ghc-prim/./GHC/IntWord64.hs libraries/ghc-prim/./GHC/Tuple.hs libraries/ghc-prim/./GHC/Types.hs libraries/ghc-prim/dist-install/build/autogen/GHC/Prim.hs +RTS -tlibraries /ghc-prim/dist-install/doc/html/ghc-prim/ghc-prim.haddock.t --machine- readable Haddock coverage: 100% ( 1 / 1) in 'GHC.IntWord64' 78% ( 7 / 9) in 'GHC.Types' 3% ( 2 / 63) in 'GHC.Tuple' 0% ( 0 / 3) in 'GHC.Debug' 0% ( 0 /351) in 'GHC.PrimopWrappers' 2% ( 1 / 43) in 'GHC.PrimWrappers' 17% ( 1 / 6) in 'GHC.CString' 31% (170 /540) in 'GHC.Prim' 100% ( 3 / 3) in 'GHC.Magic' 38% ( 6 / 16) in 'GHC.Classes' haddock: internal error: haddock: panic! (the 'impossible' happened) (GHC version 7.7.20130912 for x86_64-unknown-linux): Static flags have not been initialised! Please call GHC.newSession or GHC.parseStaticFlags early enough. Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug make[1]: *** [libraries/ghc-prim/dist-install/doc/html/ghc-prim/ghc- prim.haddock] Error 1 make[1]: *** Waiting for unfinished jobs.... make: *** [all] Error 2 }}} I've seen this problem before, but I thought that it was related to my patch. Now I got it on master branch and Luite reported the same problem on #ghc (log above is actually his). A workaround for this is disabling building of dicumentation in "perf" section of `build.mk`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8276> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9965: getChanContents BlockedIndefinitelyOnMVar on 7.10 RC1
by GHC 08 Apr '15

08 Apr '15

#9965: getChanContents BlockedIndefinitelyOnMVar on 7.10 RC1 -------------------------------------+------------------------------------- Reporter: jberryman | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: | Version: 7.10.1-rc1 libraries/base | Operating System: Unknown/Multiple Keywords: | Type of failure: Incorrect result Architecture: | at runtime Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- All of the stanzas work on 7.8.3, but the middle one works incorrectly on 7.10: {{{#!hs module Main where import Control.Concurrent.Chan import Control.Monad main = do io <- newChan let inp = [0] :: [Int] mapM_ (writeChan io) inp {- -- WORKS: outp <- getChanContents io if 0 == head outp then putStrLn "OK" else error $ "Smoke test failed" -} -- BROKEN ON 7.10 (BlockedIndefinitelyOnMVar): outp <- getChanContents io if and (zipWith (==) inp outp) then putStrLn "OK" else error $ "Smoke test failed" {- -- WORKS: forM_ inp $ \xIn-> do xOut <- readChan io unless (xIn == xOut) $ error $ "Smoke test failed" -} }}} I first noticed the behavior in a Chan-like library I wrote, whose internals are completely different from Chan, but where the getChanContents is a copy-paste from Chan. So I assume it has something to do with `unsafeInterleaveIO`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9965> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9160: Panic: Template variable unbound in rewrite rule
by GHC 08 Apr '15

08 Apr '15

#9160: Panic: Template variable unbound in rewrite rule ----------------------------------+--------------------------------------- Reporter: mietek | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: MacOS X Architecture: x86_64 (amd64) | Type of failure: Compile-time crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+--------------------------------------- Installing `singletons-1.0` with GHC 7.8.2 on OS X 10.9.2 fails: {{{ ghc: panic! (the 'impossible' happened) (GHC version 7.8.2 for x86_64-apple-darwin): Template variable unbound in rewrite rule }}} Full build log attached. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9160> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9964: GHC crash with NOINLINE and weird IO stuff
by GHC 07 Apr '15

07 Apr '15

#9964: GHC crash with NOINLINE and weird IO stuff -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- {{{#!hs {-# LANGUAGE UnboxedTuples #-} module Crash where import GHC.Base crash :: IO Int crash = IO (\s -> let {-# NOINLINE s' #-} s' = s in (# s', 1::Int #)) }}} This compiles under 7.6.3, but both 7.8.3 and head choke: {{{ ghc: panic! (the 'impossible' happened) (GHC version 7.8.3 for x86_64-unknown-linux): StgCmmEnv: variable not found s{v sLw} [lid] local binds for: Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9964> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9958: System.IO.Error: Fix a documentation link to Control.Exception.Exception
by GHC 07 Apr '15

07 Apr '15

#9958: System.IO.Error: Fix a documentation link to Control.Exception.Exception -------------------------------------+------------------------------------- Reporter: mineo | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: | Version: 7.8.4 libraries/base | Operating System: Unknown/Multiple Keywords: | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- On http://hackage.haskell.org/package/base-4.7.0.2/docs/System-IO- Error.html, the link to Control.Exception.Exception in the sentence "For a more general type of exception, including also those that arise in pure code, see Control.Exception.Exception." is broken because (in the source) it's a link to a module, but C.E.E is a type. Changing the double to single quotes fixes that. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9958> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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