April 2015 - ghc-tickets

[GHC] #9399: CPP does not process test case enum01.hs correctly
by GHC 25 May '16

25 May '16

#9399: CPP does not process test case enum01.hs correctly -------------------------------------+------------------------------------- Reporter: jrp | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Test Suite | Version: 7.8.3 Keywords: cpp | Operating System: MacOS X Architecture: x86_64 (amd64) | Type of failure: GHC Difficulty: Unknown | rejects valid program Blocked By: | Test Case: enum01.hs Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- The printTest cpp macro does not seem to be being applied in the test suite test enum01.hs (libraries/base) {{{ > ghci -cpp enum01.hs GHCi, version 7.8.3: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. [1 of 1] Compiling Main ( enum01.hs, interpreted ) enum01.hs:91:3: Not in scope: ‘printTest’ enum01.hs:92:3: Not in scope: ‘printTest’ : }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9399> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8914: Remove unnecessary constraints from MonadComprehensions and ParallelListComp
by GHC 25 May '16

25 May '16

#8914: Remove unnecessary constraints from MonadComprehensions and ParallelListComp -------------------------------------------+------------------------------- Reporter: Iceland_jack | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler (Type checker) | Version: Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Difficult (2-5 days) | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: -------------------------------------------+------------------------------- Many parts of MonadComprehensions don't actually require monads instance, the following could do with a `Functor` constraint {{{ fmapM :: Monad m => (a -> b) -> m a -> m b fmapM f xs = [ f x | x <- xs ] }}} and I don't see any reason why the class `MonadZip` (from [http://hackage.haskell.org/package/base-4.4.0.0/docs/Control-Monad- Zip.html Control.Monad.Zip]) requires a `Monad` constraint rather a `Functor` constraint: {{{ class Functor f => FunctorZip f where fzip :: f a -> f b -> f (a,b) fzip = fzipWith (,) fzipWith :: (a -> b -> c) -> f a -> f b -> f c fzipWith f fa fb = fmap (uncurry f) (fzip fa fb) funzip :: f (a,b) -> (f a, f b) funzip fab = (fmap fst fab, fmap snd fab) }}} with the laws {{{ fmap (f *** g) (fzip fa fb) = fzip (fmap f fa) (fmap g fb) fmap (const ()) fa = fmap (const ()) fb ==> funzip (fzip fa fb) = (fa, fb) }}} Same with `Applicative` (see ApplicativeDo): {{{ liftA2 :: Applicative f => (a -> b -> c) -> f a -> f b -> f c liftA2 f a1 a2 = [ f x1 x2 | x1 <- a1, x2 <- a2 ] }}} The reason I bring this up is because I'm writing a DSL that uses length- indexed vectors whose `Functor` and `FunctorZip` instances are trivial but whose `Monad` instance is [http://stackoverflow.com/questions/5802628 /monad-instance-of-a-number-parameterised-vector complicated] and not need. This proposal shares a similar rationale as ApplicativeDo. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8914> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9526: Add missing Generic instances in base
by GHC 25 May '16

25 May '16

#9526: Add missing Generic instances in base -------------------------------------+------------------------------------- Reporter: nh2 | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.10.1 Component: libraries/base | Version: 7.8.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Moderate (less | Type of failure: than a day) | None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Most primitive types (`Int`, `Char`, etc.) have a GHC.Generics.Generic instance, but some are missing, such as `Integer` and the various `Word*` data types. We should consistently have instances for all primitive types offered by base, since they are required if you want to derive a Generic instance for any type that contains them. I boldly set the milestone to 7.10 because I naively assume this should be straightforward. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9526> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8990: Performance tests behave differently depending on presence of .hi file (even with -fforce-recomp)
by GHC 23 May '16

23 May '16

#8990: Performance tests behave differently depending on presence of .hi file (even with -fforce-recomp) ------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Test Suite | Version: 7.9 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Example: {{{ [ezyang@hs01 compiler]$ cat T6048.comp.stats /home/hs01/ezyang/ghc-compalloc/inplace/lib/bin/ghc-stage2 -B/home/hs01/ezyang/ghc-compalloc/inplace/lib -fforce-recomp -dno-debug- output -no-user-package-db -rtsopts -fno-ghci-history -c T6048.hs -O -fasm +RTS -V0 -tT6048.comp.stats --machine-readable [("bytes allocated", "119871672") ,("num_GCs", "100") ,("average_bytes_used", "4388904") ,("max_bytes_used", "12539576") ,("num_byte_usage_samples", "7") ,("peak_megabytes_allocated", "27") ,("init_cpu_seconds", "0.00") ,("init_wall_seconds", "0.00") ,("mutator_cpu_seconds", "0.09") ,("mutator_wall_seconds", "0.10") ,("GC_cpu_seconds", "0.15") ,("GC_wall_seconds", "0.15") ] [ezyang@hs01 compiler]$ rm T6048.hi [ezyang@hs01 compiler]$ '/home/hs01/ezyang/ghc-compalloc/inplace/bin/ghc- stage2' -fforce-recomp -dno-debug-output -no-user-package-db -rtsopts -fno-ghci-history -c T6048.hs -O -fasm +RTS -V0 -tT6048.comp.stats --machine-readable -RTS [ezyang@hs01 compiler]$ cat T6048.comp.stats /home/hs01/ezyang/ghc-compalloc/inplace/lib/bin/ghc-stage2 -B/home/hs01/ezyang/ghc-compalloc/inplace/lib -fforce-recomp -dno-debug- output -no-user-package-db -rtsopts -fno-ghci-history -c T6048.hs -O -fasm +RTS -V0 -tT6048.comp.stats --machine-readable [("bytes allocated", "121022912") ,("num_GCs", "100") ,("average_bytes_used", "4022069") ,("max_bytes_used", "11224944") ,("num_byte_usage_samples", "7") ,("peak_megabytes_allocated", "25") ,("init_cpu_seconds", "0.00") ,("init_wall_seconds", "0.00") ,("mutator_cpu_seconds", "0.09") ,("mutator_wall_seconds", "0.11") ,("GC_cpu_seconds", "0.15") ,("GC_wall_seconds", "0.14") ] }}} It's a slight but present difference: I noticed because one of the perf tests was failing on an initial run of the test suite, but passing when I re-ran it. There are two possible bugs here. One is that our implementation of `-fforce-recomp` is buggy and we shouldn't be reading in the hi file at all if `-fforce-recomp` is on; the other is that we should always clean up interface files before running one of these perf tests. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8990> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9095: make sdist picks up test files
by GHC 22 May '16

22 May '16

#9095: make sdist picks up test files ------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Build System | Version: 7.9 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- I recently ran 'make sdist' and discovered that I my source tarball was nearly a gigabyte large. Closer inspection revealed that sdist had slurped up executable files for tests that I had run at some point. It would be preferable if 'make sdist' did not do that. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9095> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9298: ghc.exe: internal error: evacuate: strange closure type 365488164
by GHC 21 May '16

21 May '16

#9298: ghc.exe: internal error: evacuate: strange closure type 365488164 ------------------------------+--------------------------------------- Reporter: Tominator2 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: idris | Operating System: Windows Architecture: x86 | Type of failure: Compile-time crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------+--------------------------------------- after saying "cabal install idris" the machine churned for a while, spitting out messages, then said: src\Idris\AbsSyntax.hs:1569:10: Warning: `EitherErr' is an instance of Monad but not Applicative - this will become an error in GHC 7.10, under the Applicative-Monad Proposal. ghc.exe: internal error: evacuate: strange closure type 365488164 (GHC version 7.8.2 for x86_64_unknown_mingw32) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. Failed to install idris-0.9.13.1 cabal.exe: Error: some packages failed to install: idris-0.9.13.1 failed during the building phase. The exception was: ExitFailure 3 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9298> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9059: Excessive space usage while generating code for fractional literals with big exponents
by GHC 19 May '16

19 May '16

#9059: Excessive space usage while generating code for fractional literals with big exponents ------------------------------------+------------------------------------- Reporter: basvandijk | Owner: Type: bug | 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: | ------------------------------------+------------------------------------- Generating (byte-)code for fractional literals with big exponents causes excessive space usage: {{{ $ ghci -ddump-bcos GHCi, version 7.6.3: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Prelude> let r=1e1000 :: Rational ==================== Proto-BCOs ==================== ProtoBCO ExprTopLevel_E0#0 []: let sat_so4 = ... in ... bitmap: 0 [] ALLOC_AP 0 PUSH_BCO ProtoBCO sat_so4#0 []: let sat_snX = ... in ... bitmap: 0 [] PUSH_UBX (1) 1 PACK GHC.Integer.Type.S# 1 ALLOC_AP 0 PUSH_BCO ProtoBCO sat_snY#0 []: let sat_siH = ... in ... bitmap: 0 [] STKCHECK 544 PUSH_UBX (1) 30 PACK GHC.Types.I# 1 PUSH_G GHC.Types.[] PUSH_L 1 PACK : 2 PUSH_UBX (1) 953884573 PACK GHC.Types.I# 1 PUSH_LL 1 0 PACK : 2 PUSH_UBX (1) 1777164331 PACK GHC.Types.I# 1 PUSH_LL 1 0 PACK : 2 PUSH_UBX (1) 1665817172 PACK GHC.Types.I# 1 PUSH_LL 1 0 PACK : 2 PUSH_UBX (1) 1937337765 PACK GHC.Types.I# 1 PUSH_LL 1 0 PACK : 2 PUSH_UBX (1) 799142572 PACK GHC.Types.I# 1 PUSH_LL 1 0 PACK : 2 PUSH_UBX (1) 1439062260 PACK GHC.Types.I# 1 PUSH_LL 1 0 PACK : 2 PUSH_UBX (1) 1049546550 PACK GHC.Types.I# 1 PUSH_LL 1 0 PACK : 2 PUSH_UBX (1) 580758741 PACK GHC.Types.I# 1 PUSH_LL 1 0 PACK : 2 PUSH_UBX (1) 139570364 PACK GHC.Types.I# 1 PUSH_LL 1 0 PACK : 2 ... }}} Increasing the exponent to say a 1000000 will quickly fill up the memory of my machine. A similar problem occurs while compiling: !BigExponentBug.hs: {{{ module BigExponentBug (r) where r = 1e100 :: Rational }}} {{{ ghc --make BigExponentBug.hs -ddump-simpl [1 of 1] Compiling BigExponentBug ( BigExponentBug.hs, BigExponentBug.o ) ==================== Tidy Core ==================== Result size of Tidy Core = {terms: 9, types: 5, coercions: 0} BigExponentBug.r :: GHC.Real.Rational [GblId] BigExponentBug.r = GHC.Real.fromRational @ GHC.Real.Rational (GHC.Real.$fFractionalRatio @ GHC.Integer.Type.Integer (GHC.Real.$fNumRatio @ GHC.Integer.Type.Integer GHC.Real.$fIntegralInteger) GHC.Real.$fIntegralInteger) (GHC.Real.:% @ GHC.Integer.Type.Integer (__integer 10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000) (__integer 1)) }}} Again increasing the exponent to 1000000 quickly invokes the OOM killer on my machine. P.S. This bug was discovered while fixing a [https://github.com/bos/aeson/issues/198 related bug] in `aeson`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9059> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8207: Show instance for Language in DynFlags
by GHC 17 May '16

17 May '16

#8207: Show instance for Language in DynFlags ------------------------------------+------------------------------------- Reporter: Fuuzetsu | Owner: Type: feature request | Status: new Priority: low | Milestone: Component: GHC API | 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: | ------------------------------------+------------------------------------- I feel that the GHC API could benefit from a Show instance for Language in DynFlags.hs. Currently, if we want to display the language being used we have to do something like {{{ foo inf = case hmi_language inf of Nothing -> Nothing Just Haskell98 -> Just "Haskell98" Just Haskell2010 -> Just "Haskell2010" }}} This is pretty much just the Show instance (over Maybe) and Haskell can derive it for us automatically: we just need to change `deriving Enum` to `deriving (Enum, Show)`. The above solution is not the most robust ever as if this data type is ever changed, this starts to form an incomplete pattern. If we have a catch all `_`, GHC complains about overlapping patterns. Easily solved with `show <$> hmi_language inf`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8207> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10333: hs-boot modification doesn't induce recompilation
by GHC 16 May '16

16 May '16

#10333: hs-boot modification doesn't induce recompilation -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC accepts Unknown/Multiple | invalid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- Consider these modules: X.hs-boot {{{ module X where }}} Y.hs {{{ module Y where import {-# SOURCE #-} X data T = T data S = S T }}} X.hs {{{ module X where import Y }}} `ghc --make Y.hs` will compile fine. Now, modify `X.hs-boot` to add a `data T` (which will cause an ambiguous identifier error in Y.hx`. Run `ghc --make Y.hs` and nothing happens! (You might also notice something else a bit funny, which is that `X.hs` gets compiled, even though it's not directly in the import chain of Y. I think this might be intentional but I'm not sure.) Discovered this while poking around #10182. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10333> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10181: Lint check: arity invariant
by GHC 11 May '16

11 May '16

#10181: Lint check: arity invariant -------------------------------------+------------------------------------- Reporter: nomeata | Owner: nomeata Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- The Arity of an ID should not exceed the arity of its type, nor the arity of its strictness signature, if it is a bottoming signatures. This should be checked by a lint check (suggested by SPJ in https://phabricator.haskell.org/D747?id=2498#inline-6058) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10181> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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