August 2018 - ghc-tickets

[GHC] #15158: T8089 failing with ghci, threaded1, threaded2, profthreaded
by GHC 21 Aug '18

21 Aug '18

#15158: T8089 failing with ghci, threaded1, threaded2, profthreaded -------------------------------------+------------------------------------- Reporter: alpmestan | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: | Version: 8.5 libraries/base | Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Incorrect result (amd64) | at runtime Test Case: T8089 | Blocked By: Blocking: | Related Tickets: #8089 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{ =====> T8089(ghci) 17 of 17 [2, 16, 0] cd "/run/user/1001/ghctest-m_wu2f4i/test spaces/../../libraries/base/tests/T8089.run" && "/home/alp/WT/ghc-slow- validate/bindisttest/install dir/bin/ghc" T8089.hs -dcore-lint -dcmm- lint -no-user-package-db -rtsopts -fno-warn-missed-specialisations -fshow- warning-groups -fdiagnostics-color=never -fno-diagnostics-show-caret -dno- debug-output --interactive -v0 -ignore-dot-ghci -fno-ghci-history +RTS -I0.1 -RTS < T8089.genscript Wrong exit code for T8089(ghci) (expected 99 , actual 0 ) *** unexpected failure for T8089(ghci) =====> T8089(threaded1) 17 of 17 [2, 17, 0] cd "/run/user/1001/ghctest-m_wu2f4i/test spaces/../../libraries/base/tests/T8089.run" && "/home/alp/WT/ghc-slow- validate/bindisttest/install dir/bin/ghc" -o T8089 T8089.hs -dcore-lint -dcmm-lint -no-user-package-db -rtsopts -fno-warn-missed-specialisations -fshow-warning-groups -fdiagnostics-color=never -fno-diagnostics-show- caret -dno-debug-output -threaded -debug cd "/run/user/1001/ghctest-m_wu2f4i/test spaces/../../libraries/base/tests/T8089.run" && ./T8089 Wrong exit code for T8089(threaded1)(expected 99 , actual 0 ) *** unexpected failure for T8089(threaded1) =====> T8089(threaded2) 17 of 17 [2, 18, 0] cd "/run/user/1001/ghctest-m_wu2f4i/test spaces/../../libraries/base/tests/T8089.run" && "/home/alp/WT/ghc-slow- validate/bindisttest/install dir/bin/ghc" -o T8089 T8089.hs -dcore-lint -dcmm-lint -no-user-package-db -rtsopts -fno-warn-missed-specialisations -fshow-warning-groups -fdiagnostics-color=never -fno-diagnostics-show- caret -dno-debug-output -O -threaded -eventlog cd "/run/user/1001/ghctest-m_wu2f4i/test spaces/../../libraries/base/tests/T8089.run" && ./T8089 +RTS -N2 -ls -RTS Wrong exit code for T8089(threaded2)(expected 99 , actual 0 ) *** unexpected failure for T8089(threaded2) =====> T8089(profthreaded) 17 of 17 [2, 19, 0] cd "/run/user/1001/ghctest-m_wu2f4i/test spaces/../../libraries/base/tests/T8089.run" && "/home/alp/WT/ghc-slow- validate/bindisttest/install dir/bin/ghc" -o T8089 T8089.hs -dcore-lint -dcmm-lint -no-user-package-db -rtsopts -fno-warn-missed-specialisations -fshow-warning-groups -fdiagnostics-color=never -fno-diagnostics-show- caret -dno-debug-output -O -prof -static -fprof-auto -threaded cd "/run/user/1001/ghctest-m_wu2f4i/test spaces/../../libraries/base/tests/T8089.run" && ./T8089 +RTS -p -RTS Wrong exit code for T8089(profthreaded)(expected 99 , actual 0 ) *** unexpected failure for T8089(profthreaded) }}} I'm going to write a patch to expect the test to be broken in these ways, but it seems really wrong that the exit code we get is not the same accross all ways. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15158> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15545: Forced to enable TypeInType because of (i ~ i)
by GHC 21 Aug '18

21 Aug '18

#15545: Forced to enable TypeInType because of (i ~ i) -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 Keywords: TypeInType | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I don't know if this is a bug but `i ~ i` holds by reflexivity so I would not have expected it to require `TypeInType` {{{ $ ghci -ignore-dot-ghci GHCi, version 8.5.20180128: http://www.haskell.org/ghc/ :? for help Prelude> :set -XPolyKinds -XGADTs Prelude> import Data.Kind Prelude Data.Kind> data NP :: (k -> Type) -> (i -> Type) where NP :: f a -> NP f a <interactive>:3:45: error: • Data constructor ‘NP’ constrains the choice of kind parameter: i ~ i Use TypeInType to allow this • In the definition of data constructor ‘NP’ In the data type declaration for ‘NP’ Prelude Data.Kind> }}} I would rather expect the warning I get after enabling `TypeInType` {{{ Prelude Data.Kind> :set -XTypeInType Prelude Data.Kind> data NP :: (k -> Type) -> (i -> Type) where NP :: f a -> NP f a <interactive>:8:28: error: • Couldn't match ‘k’ with ‘i’ • In the data declaration for ‘NP’ }}} ---- '''ps''' making sure this is OK as well; it works after enabling `-XTypeInType` and quantifying with `-XRankNTypes` (is this using polymorphic recursion?) {{{ Prelude Data.Kind> :set -XTypeInType -XRankNTypes Prelude Data.Kind> data NP :: forall i k. (k -> Type) -> (i -> Type) where NP :: f a -> NP f a Prelude Data.Kind> :t NP NP :: forall i (f :: i -> *) (a :: i). f a -> NP f a }}} it also works for {{{#!hs data NP :: forall k. (k -> Type) -> (i -> Type) where NP :: f a -> NP f a data NP :: forall i. (k -> Type) -> (i -> Type) where NP :: f a -> NP f a data NP :: (k -> Type) -> forall i. (i -> Type) where NP :: f a -> NP f a }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15545> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15487: "Ambiguos occurrence" error message uses strange qualification
by GHC 21 Aug '18

21 Aug '18

#15487: "Ambiguos occurrence" error message uses strange qualification -------------------------------------+------------------------------------- Reporter: j.waldmann | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 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: -------------------------------------+------------------------------------- The following text produces an error message that I find somewhat confusing. This issue is just about the wording of the message. {{{#!hs module A (null) where { } module B where { import qualified A ; null = 42 ; main = null } }}} when I load `B` in ghci, I get {{{ B.hs:1:58: error: Ambiguous occurrence ‘null’ It could refer to either ‘A.null’, imported from ‘Prelude’ at B.hs:1:8 (and originally defined in ‘Data.Foldable’) or ‘B.null’, defined at B.hs:1:39 }}} I think ".. could refer to A.null" looks strange. I would expect `Prelude.null` here, which I do get when I remove "import qualified A" from the text of `B`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15487> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15505: Assertion failure in test T7224
by GHC 21 Aug '18

21 Aug '18

#15505: Assertion failure in test T7224 -------------------------------------+------------------------------------- Reporter: osa1 | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.5 (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: -------------------------------------+------------------------------------- To reproduce, build GHC HEAD with slow validate settings, then run test `T7224`. Output: {{{ =====> T7224(normal) 9 of 15 [0, 2, 0] cd "polykinds/T7224.run" && "/home/omer/haskell/ghc/inplace/test spaces /ghc-stage2" -c T7224.hs -dcore-lint -dcmm-lint -no-user-package-db -rtsopts -fno-warn-missed-specialisations -fshow-warning-groups -fdiagnostics-color=never -fno-diagnostics-show-caret -dno-debug-output Actual stderr output differs from expected: diff -uw "polykinds/T7224.run/T7224.stderr.normalised" "polykinds/T7224.run/T7224.comp.stderr.normalised" --- polykinds/T7224.run/T7224.stderr.normalised 2018-08-11 13:33:16.874459507 +0300 +++ polykinds/T7224.run/T7224.comp.stderr.normalised 2018-08-11 13:33:16.874459507 +0300 @@ -1,13 +1,11 @@ +ghc: panic! (the 'impossible' happened) + (GHC version 8.7.20180809 for x86_64-unknown-linux): + ASSERT failed! + Type-correct unfilled coercion hole {co_asw} + Call stack: + CallStack (from HasCallStack): + callStackDoc, called at compiler/utils/Outputable.hs:<line>:<column> in <package-id>:Outputable + pprPanic, called at compiler/utils/Outputable.hs:<line>:<column> in <package-id>:Outputable + assertPprPanic, called at compiler/typecheck/TcHsSyn.hs:<line>:<column> in <package-id>:TcHsSyn -T7224.hs:6:19: - Expected kind ‘i’, but ‘i’ has kind ‘*’ - In the first argument of ‘m’, namely ‘i’ - In the type signature: ret' :: a -> m i i a - In the class declaration for ‘PMonad'’ - -T7224.hs:7:14: - Expected kind ‘i’, but ‘i’ has kind ‘*’ - In the first argument of ‘m’, namely ‘i’ - In the type signature: - bind' :: m i j a -> (a -> m j k b) -> m i k b - In the class declaration for ‘PMonad'’ +Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug *** unexpected failure for T7224(normal) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15505> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15553: GHC.IO.Encoding not flushing partially converted input
by GHC 21 Aug '18

21 Aug '18

#15553: GHC.IO.Encoding not flushing partially converted input -------------------------------------+------------------------------------- Reporter: msakai | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Core | Version: 8.4.3 Libraries | Keywords: | Operating System: Linux Architecture: | Type of failure: Incorrect result Unknown/Multiple | at runtime Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Conversion by `GHC.IO.Encoding` produces incomplete output for some encodings because it does not flush ''partially converted input'' at the end of the string. [https://manpages.debian.org/stretch/manpages-dev/iconv.3 iconv(3)] provides API for the flushing. > In each series of calls to iconv(), the last should be one with inbuf or *inbuf equal to NULL, in order to flush out any partially converted input. But `GHC.IO.Encoding` does not perform the flushing properly and it can cause incomplete conversion result. I found two cases that it actually produces incomplete output, but there might be more cases. = Case 1: EUC-JISX0213 For example, the following code is expected to output two bytes 0xa4 0xb1, but it outputs none. {{{#!hs enc <- mkTextEncoding "EUC-JISX0213" withFile "test.txt" WriteMode $ \h -> hSetEncoding h enc >> hPutStr h "\x3051" }}} The problem happens because of the following mapping between Unicode and EUC-JISX0213. ||Unicode||EUC-JISX0213|| ||U+3051 U+309A||0xa4 0xfa|| ||U+3051||0xa4 0xb1|| After seeing the codepoint U+3051, the converter is unable to determine which of the two byte sequence to output until it sees the next character or ''the end of the string''. But `GHC.IO.Encoding` does not call the above mentioned ''flushing'' API, therefore the converter is unable to recognize the end of the string. = Case 2: ISO-2022-JP Similarly, following code is expected to output byte sequence `0x1b 0x24 0x42` `0x24 0x22` `0x1b 0x28 0x42` but the last three bytes `0x1b 0x28 0x42` is not produced. {{{#!hs enc <- mkTextEncoding "ISO-2022-JP" withFile "test.txt" WriteMode $ \h -> hSetEncoding h enc >> hPutStr h "\x3042" }}} ISO-2022-JP is a stateful encoding and [https://www.ietf.org/rfc/rfc1468.txt RFC 1468] requires the state is reset to initial state at the end of the string. The missing three bytes `0x1b 0x28 0x42` are the escape sequence for that purpose. But again `GHC.IO.Encoding` does not call the above mentioned`flushing` API, therefore the converter cannot recognize the end of the string and cannot reset the state. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15553> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15504: -XStrict doesn't prevent warnings from -Wunbanged-strict-patterns
by GHC 21 Aug '18

21 Aug '18

#15504: -XStrict doesn't prevent warnings from -Wunbanged-strict-patterns -------------------------------------+------------------------------------- Reporter: ChaiTRex | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 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: -------------------------------------+------------------------------------- I'm using: {{{ $ ghc --version The Glorious Glasgow Haskell Compilation System, version 8.4.3 }}} I was under the impression that [https://ghc.haskell.org/trac/ghc/wiki/StrictPragma#Strict -XStrict] automatically included outermost bang patterns, but either that isn't always the case or [https://downloads.haskell.org/~ghc/master/users-guide /using-warnings.html#ghc-flag--Wunbanged-strict-patterns -Wunbanged- strict-patterns] doesn't know that `-XStrict` did its job correctly: {{{#!hs {-# OPTIONS_GHC -Wunbanged-strict-patterns #-} {-# LANGUAGE BangPatterns, MagicHash, Strict, UnboxedTuples #-} module Example where import GHC.Exts (Int(I#), quotRemInt#) lastDigit :: Int -> Int lastDigit (I# x) = let (# q, r #) = quotRemInt# x 10# in I# r }}} compiles with a warning: {{{ [1 of 1] Compiling Example ( Example.hs, Example.o ) Example.hs:9:24: warning: [-Wunbanged-strict-patterns] Pattern bindings containing unlifted types should use an outermost bang pattern: (# q, r #) = quotRemInt# x 10# | 9 | lastDigit (I# x) = let (# q, r #) = quotRemInt# x 10# | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15504> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9854: Literal overflow check is too aggressive
by GHC 21 Aug '18

21 Aug '18

#9854: Literal overflow check is too aggressive -------------------------------------+------------------------------------- Reporter: tibbe | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- The literal overflow check is too aggressive. Sometimes you want to give a literal as a hexadecimal value that does fit inside e.g. an `Int`, like so: {{{ Prelude> 0xdc36d1615b7400a4 :: Int <interactive>:2:1: Warning: Literal 15868100553162883236 is out of the Int range -9223372036854775808..9223372036854775807 -2578643520546668380 }}} However the compiler complains because of the wrap-around. I feel this is common enough and practice (and perfectly well-defined) that the compiler shouldn't warn. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9854> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12467: distclean does not clean 'compact' library
by GHC 21 Aug '18

21 Aug '18

#12467: distclean does not clean 'compact' library -------------------------------------+------------------------------------- Reporter: osa1 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Build System | Version: 8.1 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: -------------------------------------+------------------------------------- {{{ > ghc_2 git:(master) make distclean 2>&1 | grep compact > ghc_2 git:(master) }}} I think we should see something like {{{ "rm" -rf libraries/compact/dist-install }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12467> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15547: A function `nat2Word# :: KnownNat n => Proxy# n -> Word#`
by GHC 21 Aug '18

21 Aug '18

#15547: A function `nat2Word# :: KnownNat n => Proxy# n -> Word#` -------------------------------------+------------------------------------- Reporter: ChaiTRex | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 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: -------------------------------------+------------------------------------- It would be nice if there were the function (perhaps in `GHC.Prim`) `nat2Word# :: KnownNat n => Proxy# n -> Word#` that was essentially `(\ W# w# -> w#) . fromInteger . natVal`, except that it produces the `Word#` at compile-time rather than runtime and that it works with `Proxy#` (for [https://hackage.haskell.org/package/base-4.11.1.0/docs/GHC- Exts.html#t:Proxy-35- its no-runtime-representation, totally-free nature]) instead of `Proxy`. This would enable compile-time computations on `Nat`s to produce a literal `Word#` without any runtime expense at all, which seems nice if you're dealing with primitives ''because'' you want to avoid runtime expense. == Motivating example I'm learning primitive types and type-level arithmetic by making a simple set of fixed-width integer types where the type contains a `Nat` for the number of bits in the fixed-width integer. Going from the following `Nat`s to their corresponding `Word#`s at compile time even when optimizations are turned off during development would be very nice: ||= `Div (n + 63) 64` \\=||the highest index we should try to access via `indexWordArray#` || ||= `Mod (n - 1) 64 + 1` \\=||except when `n == 0`, the number of bits actually used in the \\ most-significant word || ||= `2^(Mod (n + 63) 64 + 1) - 1` \\=||the unsigned integer narrowing bitmask to use on the \\ most-significant word || -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15547> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15513: How to pass "-hide-all-packages" to the GHC API?
by GHC 20 Aug '18

20 Aug '18

#15513: How to pass "-hide-all-packages" to the GHC API? -------------------------------------+------------------------------------- Reporter: lspitzner | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: 8.6.1 Component: Documentation | Version: 8.4.3 Keywords: environment | Operating System: Unknown/Multiple file API | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- In brittany, we have make use of the GHC API e.g. in the following fashion: {{{#!hs parseModuleFromString :: [String] -> System.IO.FilePath -> (GHC.DynFlags -> IO (Either String a)) -> String -> IO (Either String (ExactPrint.Anns, GHC.ParsedSource, a)) parseModuleFromString args fp dynCheck str = mask_ $ ExactPrint.ghcWrapper $ ExceptT.runExceptT $ do dflags0 <- lift $ ExactPrint.initDynFlagsPure fp str (dflags1, leftover, warnings) <- lift $ GHC.parseDynamicFlagsCmdLine dflags0 (GHC.noLoc <$> args) when (not $ null leftover) $ ExceptT.throwE $ "when parsing ghc flags: leftover flags: " ++ show (leftover <&> \(L _ s) -> s) when (not $ null warnings) $ ExceptT.throwE $ "when parsing ghc flags: encountered warnings: " ++ show (warnings <&> warnExtractorCompat) dynCheckRes <- ExceptT.ExceptT $ liftIO $ dynCheck dflags1 let res = ExactPrint.parseModuleFromStringInternal dflags1 fp str case res of Left (span, err) -> ExceptT.throwE $ show span ++ ": " ++ err Right (a , m ) -> pure (a, m, dynCheckRes) }}} This code unfortunately picks up "package environment files", which I take it is not at all necessary for this use-case: Brittany only requires parsing functionality, so external packages should be irrelevant. "Unfortunately", because the package environment files can easily become stale, which in turn breaks the API. The users' guide mentions the "-hide-all-packages" flag, but my attempts to pass this to the API so far have failed. What I have tried is calling `parseDynamicFlagsCmdLine` with "-hide-all-packages" as an argument, and using the resulting dynflags afterwards. This appears to be without effect, I think even when it is the first thing executed inside of `runGhc`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15513> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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