November 2017 - ghc-tickets

[GHC] #14291: Tests tend to fail in the ext-interp when testing a tree built with a source distribution
by GHC 25 Feb '18

25 Feb '18

#14291: Tests tend to fail in the ext-interp when testing a tree built with a source distribution -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 8.2.1 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: -------------------------------------+------------------------------------- One issue I've noticed while working on #13716 is that most (if not all) of the tests runs in the `ext-interp` way fail when run inside a tree derived from a source distribution tarball. For instance, {{{ $ git clone git://git.haskell.org/ghc $ cd ghc $ git submodule update --init $ mk/get-win32-tarballs.sh download all $ ./boot $ ./configure $ make sdist $ mkdir tmp; cd tmp $ ls ../sdistprep/ghc-*-src.tar.xz | xargs -n1 tar -xf $ cd ghc-* $ ./boot $ ./configure $ make -j9 $ make test TEST=T10638 ... =====> T10638(normal) 1 of 1 [0, 0, 0] cd "./th/T10638.run" && "/mnt/work/ghc/ghc- testing/temp/ghc-8.3.20170927/inplace/bin/ghc-stage2" -c T10638.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 -XTemplateHaskell -package template-haskell -v0 =====> T10638(ext-interp) 1 of 1 [0, 0, 0] cd "./th/T10638.run" && "/mnt/work/ghc/ghc- testing/temp/ghc-8.3.20170927/inplace/bin/ghc-stage2" -c T10638.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 -XTemplateHaskell -package template-haskell -fexternal-interpreter -v0 Actual stderr output differs from expected: diff -uw "./th/T10638.run/T10638.stderr.normalised" "./th/T10638.run/T10638.comp.stderr.normalised" --- ./th/T10638.run/T10638.stderr.normalised 2017-09-27 12:18:45.737974039 -0400 +++ ./th/T10638.run/T10638.comp.stderr.normalised 2017-09-27 12:18:45.737974039 -0400 @@ -1,5 +1,18 @@ +ghc-iserv.bin: internal evacuate(static): strange closure type 16476 + (GHC version 8.3.20170927 for x86_64_unknown_linux) + Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug -T10638.hs:26:11: - ‘static test2’ is not a valid C identifier - When checking declaration: - foreign import prim safe "static test2" cmm_test2 :: Int# -> Int# +T10638.hs:26:9: + Exception when trying to run compile-time code: + {handle: <file descriptor: 11>}: GHCi.Message.remoteCall: end of file + Code: do t <- [t| Int# -> Int# |] + cmm_test2 <- newName "cmm_test2" + addTopDecls + [ForeignD (ImportF Prim Safe "static test2" cmm_test2 t)] + .... + In the untyped splice: + $(do t <- [t| Int# -> Int# |] + cmm_test2 <- newName "cmm_test2" + addTopDecls + [ForeignD (ImportF Prim Safe "static test2" cmm_test2 t)] + [| test1 |]) *** unexpected failure for T10638(ext-interp) Unexpected results from: TEST="T10638" ... }}} The crashes are generally RTS panics or segmentation faults. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14291> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13011: Simplifier ticks exhausted: a 10-line case
by GHC 25 Feb '18

25 Feb '18

#13011: Simplifier ticks exhausted: a 10-line case -------------------------------------+------------------------------------- Reporter: L.K.Rebellion | Owner: Type: bug | Status: new Priority: high | Milestone: Component: Compiler | Version: 8.0.1 Keywords: Simplifier | Operating System: Linux ticks exhausted | Type of failure: Compile-time Architecture: x86 | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: #8319 #12776 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I was trying to define a function that could take itself as an argument. {{{#!hs newtype MobiusFn a = MobiusFn { func :: MobiusFn a -> a } spin :: MobiusFn a -> a spin mf = func mf mf }}} Use it to find suffixes of a `String` {{{#!hs suffixes :: String -> [String] suffixes = spin $ MobiusFn suffixesMF where suffixesMF _ [] = [] suffixesMF mf s@(_:xs) = s : spin mf xs }}} Add `main` and compile {{{#!hs main = readLn >>= (print . suffixes) }}} The compiler panicked with {{{ [1 of 1] Compiling Main ( test.hs, test.o ) ghc: panic! (the 'impossible' happened) (GHC version 8.0.1 for i386-unknown-linux): Simplifier ticks exhausted When trying UnfoldingDone mf_s1UD }}} But if we ignore the empty string case, it works well with non-empty strings. {{{#!hs suffixes :: String -> [String] suffixes = spin $ MobiusFn suffixesMF where suffixesMF _ s@[_] = [s] suffixesMF mf s@(_:xs) = s : spin mf xs }}} Two versions tested. {{{ GHC version 8.0.1 for i386-unknown-linux GHC version 7.10.3 for i386-unknown-linux }}} Thank you for reading. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13011> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8597: Git Hook script to prevent large binary blobs being checked in
by GHC 24 Feb '18

24 Feb '18

#8597: Git Hook script to prevent large binary blobs being checked in ------------------------------------+------------------------------------- Reporter: hvr | Owner: hvr Type: task | Status: new Priority: normal | Milestone: Component: Trac & Git | Version: Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- It has already occurred in the past in `testsuite.git` repo, that executables were checked in by accident, and caused the Git history to get bloated. In order to avoid such accidents in the future a Git hook script in the style of [http://stackoverflow.com/questions/20226132/is-there-a-git-hook- which-can-prevent-binary-check-ins this] might be useful, but taking also into account the size, and/or possibly with a magic safeword to be put in the commit message, to override the check for a single commit, if the author really knows what (s)he's doing. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8597> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14542: Renamer / typechecker hang (UndecidableSuperClasses)
by GHC 24 Feb '18

24 Feb '18

#14542: Renamer / typechecker hang (UndecidableSuperClasses) -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.3 Keywords: | Operating System: Unknown/Multiple UndecidableSuperClasses | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Adapted from [https://gist.github.com/ekmett/b26363fc0f38777a637d hask], this does not look like a normal superclass loop. Loop is avoided by removing `instance (Category p, Category q) => Category (Nat p q)`. {{{#!hs {-# language KindSignatures #-} {-# language PolyKinds #-} {-# language DataKinds #-} {-# language TypeFamilies #-} {-# language RankNTypes #-} {-# language NoImplicitPrelude #-} {-# language FlexibleContexts #-} {-# language MultiParamTypeClasses #-} {-# language GADTs #-} {-# language ConstraintKinds #-} {-# language FlexibleInstances #-} {-# language TypeOperators #-} {-# language ScopedTypeVariables #-} {-# language DefaultSignatures #-} {-# language FunctionalDependencies #-} {-# language UndecidableSuperClasses #-} {-# language UndecidableInstances #-} {-# language TypeInType #-} import GHC.Types (Constraint, Type) type Cat i = i -> i -> Type newtype Y p a b = Y { getY :: p b a } class (Functor p, Dom p ~ Op p, Cod p ~ Nat p (->), Ob (Op p) ~ Ob p) => Category (p :: Cat i) where type Op p :: Cat i type Op p = Y p type Ob p :: i -> Constraint class (Category (Dom f), Category (Cod f)) => Functor (f :: i -> j) where type Dom f :: Cat i type Cod f :: Cat j data Nat :: Cat i -> Cat j -> Cat (i -> j) instance (Category p, Category q) => Category (Nat p q) }}} I get {{{ $ ghci2 -ignore-dot-ghci -v /tmp/Hangs.hs GHCi, version 8.3.20171122: http://www.haskell.org/ghc/ :? for help Glasgow Haskell Compiler, Version 8.3.20171122, stage 2 booted by GHC version 8.2.1 ... Loading package integer-gmp-1.0.1.0 ... linking ... done. Loading package base-4.11.0.0 ... linking ... done. *** Parser [source]: !!! Parser [source]: finished in 0.66 milliseconds, allocated 0.136 megabytes *** Desugar: *** Simplify [expr]: !!! Simplify [expr]: finished in 0.43 milliseconds, allocated 0.233 megabytes *** CorePrep [expr]: !!! CorePrep [expr]: finished in 0.23 milliseconds, allocated 0.167 megabytes *** ByteCodeGen [Ghci1]: !!! ByteCodeGen [Ghci1]: finished in 0.35 milliseconds, allocated 0.284 megabytes *** Parser [source]: !!! Parser [source]: finished in 0.21 milliseconds, allocated 0.197 megabytes *** Desugar: *** Simplify [expr]: !!! Simplify [expr]: finished in 0.52 milliseconds, allocated 0.268 megabytes *** CorePrep [expr]: !!! CorePrep [expr]: finished in 0.23 milliseconds, allocated 0.113 megabytes *** ByteCodeGen [Ghci1]: !!! ByteCodeGen [Ghci1]: finished in 0.46 milliseconds, allocated 0.334 megabytes *** Chasing dependencies: Chasing modules from: !!! Chasing dependencies: finished in 0.14 milliseconds, allocated 0.047 megabytes Stable obj: [] Stable BCO: [] unload: retaining objs [] unload: retaining bcos [] Ready for upsweep [] Upsweep completely successful. *** Deleting temp files: Deleting: *** Chasing dependencies: Chasing modules from: */tmp/Hangs.hs !!! Chasing dependencies: finished in 6.10 milliseconds, allocated 10.504 megabytes Stable obj: [] Stable BCO: [] unload: retaining objs [] unload: retaining bcos [] Ready for upsweep [NONREC ModSummary { ms_hs_date = 2017-11-28 22:14:57.810561584 UTC ms_mod = Main, ms_textual_imps = [(Nothing, GHC.Types)] ms_srcimps = [] }] *** Deleting temp files: Deleting: compile: input file /tmp/Hangs.hs *** Checking old interface for Main (use -ddump-hi-diffs for more details): [1 of 1] Compiling Main ( /tmp/Hangs.hs, interpreted ) *** Parser [Main]: !!! Parser [Main]: finished in 2.63 milliseconds, allocated 4.821 megabytes *** Renamer/typechecker [Main]: }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14542> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13153: Several Traversable instances have an extra fmap
by GHC 24 Feb '18

24 Feb '18

#13153: Several Traversable instances have an extra fmap -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: dfeuer Type: bug | Status: new Priority: normal | Milestone: 8.4.1 Component: Core | Version: 8.1 Libraries | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Runtime Unknown/Multiple | performance bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- For example, we define {{{#!hs instance Traversable ZipList where traverse f (ZipList xs) = ZipList <$> traverse f xs }}} If the list is very short, the extra `fmap` could be bad. We can fix this by inlining the inner `traverse`. However, I suspect a better approach would be to add a method to `Traversable`: {{{#!hs mapTraverse :: Applicative f => (t b -> r) -> (a -> f b) -> t a -> f r mapTraverse p f xs = p <$> traverse f xs }}} but I need to work through whether this is enough power to solve enough problems. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13153> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11826: unsafe causes bug, news @ 11
by GHC 24 Feb '18

24 Feb '18

#11826: unsafe causes bug, news @ 11 -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 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 know there has been plenty of levity here lately but here goes :) I didn't expect ‘isUndefined’ to be safe but this may be interesting to the devs (I am obedient and report it thusly and hereby-ly per GHC's request) {{{#!haskell % ghci -ignore-dot-ghci GHCi, version 8.1.20160117: http://www.haskell.org/ghc/ :? for help Prelude> import Control.Exception Prelude Control.Exception> import System.IO.Unsafe Prelude Control.Exception System.IO.Unsafe> import Unsafe.Coerce Prelude Control.Exception System.IO.Unsafe Unsafe.Coerce> isUndefined x = unsafePerformIO $ catch ((unsafeCoerce x :: IO ()) >> return False) (const $ return True :: SomeException -> IO Bool) Prelude Control.Exception System.IO.Unsafe Unsafe.Coerce> isUndefined (succ True) True Prelude Control.Exception System.IO.Unsafe Unsafe.Coerce> isUndefined (succ False) <interactive>: internal error: stg_ap_v_ret (GHC version 8.1.20160117 for x86_64_unknown_linux) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug Aborted (core dumped) % }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11826> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12524: RFC: Allow prefixing result evaluated at GHCi prompt
by GHC 24 Feb '18

24 Feb '18

#12524: RFC: Allow prefixing result evaluated at GHCi prompt -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature | Status: new request | Priority: lowest | Milestone: Component: GHCi | Version: 8.0.1 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: -------------------------------------+------------------------------------- Similar to `prompt`, `prompt-cont` (previously `prompt2`): allowing users to supply a prefix to evaluation results with `result` has two use cases I can think of {{{ :set prompt " ghci> " :set prompt-cont " ghci| " :set result " " }}} the desired outcome would be `↓` as indented code for IRC, also reddit code format: {{{ ghci> 1 + 2 + 3 6 ghci> reverse "hello" "olleh" }}} ---- The other case came from [https://twitter.com/rightfold/status/767301255140179968 this tweet] {{{ :set prompt "" :set result "-- " }}} {{{ 1 + 2 + 3 -- 6 reverse "hello" -- "olleh" }}} This can be copied/pasted back to a separate GHCi session where the result is ignored. ---- I haven't seen this feature in any other repl, I'm not sure if this would see much use. This wouldn't work with IO actions without some magic. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12524> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14328: ld.gold -r brokenness breaks SplitSections=YES builds
by GHC 21 Feb '18

21 Feb '18

#14328: ld.gold -r brokenness breaks SplitSections=YES builds -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: 14291 | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- See https://sourceware.org/bugzilla/show_bug.cgi?id=22266. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14328> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14536: Ghc panics while building stage2 with -dstg-lint
by GHC 21 Feb '18

21 Feb '18

#14536: Ghc panics while building stage2 with -dstg-lint -------------------------------------+------------------------------------- Reporter: duog | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.3 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: -------------------------------------+------------------------------------- Building ghc at 54fda257d4a7bfddaa0c1fa0be698d1a849c4124 with the following mk/build.mk: {{{ BuildFlavour = validate ifneq "$(BuildFlavour)" "" include mk/flavours/$(BuildFlavour).mk endif GhcStage2HcOpts += -dcore-lint -dstg-lint -dcmm-lint }}} building with: {{{ make compiler/stage2/build/Exception.o }}} panics with: {{{ ghc-stage1: panic! (the 'impossible' happened) (GHC version 8.3.20171127 for x86_64-unknown-linux): ASSERT failed! dataConInstArgTys Unit# [k0_10, a_11] ['TupleRep '[], 'IntRep, State# RealWorld, Int#] Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1208:22 in ghc:Outputable assertPprPanic, called at compiler/basicTypes/DataCon.hs:1256:76 in ghc:DataCon Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1150:37 in ghc:Outputable pprPanic, called at compiler/utils/Outputable.hs:1206:5 in ghc:Outputable assertPprPanic, called at compiler/basicTypes/DataCon.hs:1256:76 in ghc:DataCon Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} Once this is resolved, is there any reason that -dstg-ling and -dcmm-lint are not set on validate (at least with SLOW)? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14536> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14541: Stg lint failure while building ghc-stage2: compiler/stage2/build/Hoopl/Block.o
by GHC 21 Feb '18

21 Feb '18

#14541: Stg lint failure while building ghc-stage2: compiler/stage2/build/Hoopl/Block.o -------------------------------------+------------------------------------- Reporter: duog | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.3 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: -------------------------------------+------------------------------------- With the tree at: https://github.com/duog/ghc/tree/trac-14536 Which fixes ticket:14536 With build.mk: {{{ BuildFlavour = validate ifneq "$(BuildFlavour)" "" include mk/flavours/$(BuildFlavour).mk endif GhcStage2HcOpts += -dcore-lint -dstg-lint -dcmm-lint }}} building with: {{{ make compiler/stage2/build/Hoopl/Blocks.o }}} I get the following Stg lint error (extracts, full dump attached): {{{ <no location info>: warning: [in body of lambda with binders ds_s4dH :: a_a3as -> b_a3at, ds1_s4dI :: MaybeO ex_a3ao a_a3as] In some algebraic case alternative, number of arguments doesn't match constructor: JustO (arity 2) [a1_s4dK] }}} ... {{{ $fFunctorMaybeO_$cfmap :: forall ex a b. (a -> b) -> MaybeO ex a -> MaybeO ex b [GblId, Arity=2, Caf=NoCafRefs, Str=<L,1*C1(U)><S,1*U>, Unf=OtherCon []] = [] \r [ds_s4dH ds1_s4dI] case ds1_s4dI of { JustO a1_s4dK [Occ=Once] -> let { sat_s4dL [Occ=Once] :: b_a3at [LclId] = [ds_s4dH a1_s4dK] \u [] ds_s4dH a1_s4dK; } in JustO [sat_s4dL]; NothingO -> $WNothingO; }; }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14541> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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