April 2017 - ghc-tickets

[GHC] #11773: linux/powepc : ghc-stage1 segfaults when building unregisterised
by GHC 19 Mar '18

19 Mar '18

#11773: linux/powepc : ghc-stage1 segfaults when building unregisterised --------------------------------+---------------------------------------- Reporter: erikd | Owner: erikd Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 8.1 Keywords: | Operating System: Unknown/Multiple Architecture: powerpc | Type of failure: Building GHC failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------+---------------------------------------- Building unregisterised to test code paths that don't get tested in the registerised compile mode. The segfault: {{{ "inplace/bin/ghc-stage1" -static -O -H64m -Wall -Iincludes -Iincludes/dist \ -Iincludes/dist-derivedconstants/header -Iincludes/dist- ghcconstants/header \ -Irts -Irts/dist/build -DCOMPILING_RTS -this-unit-id rts -optc-DNOSMP \ -dcmm-lint -i -irts -irts/dist/build -irts/dist/build/autogen \ -Irts/dist/build -Irts/dist/build/autogen -O2 -Wnoncanonical-monad- instances \ -c rts/StgStartup.cmm -o rts/dist/build/StgStartup.o }}} seems to occur on powerpc, but not on x86_64 or armhf. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11773> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11765: Allow documentary type signatures
by GHC 19 Mar '18

19 Mar '18

#11765: Allow documentary type signatures -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: Type: feature | Status: new request | Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 7.10.3 (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: -------------------------------------+------------------------------------- In some cases (e.g., `lens`) it's useful to document a binding with a more specific type signature than the true one, to show a useful special case. Unfortunately, this documentation can potentially be wrong or go out of date. I'd like to propose a pragma for this: {{{#!hs {-# Documentary #-} f :: T -> U }}} would ask the type checker to verify that `f :: T -> U`. Specifically, it would have the effect of creating and type checking, but then discarding, a hidden binding {{{#!hs f_doc :: T -> U f_doc t = f t }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11765> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12712: break011 is broken on Windows
by GHC 19 Mar '18

19 Mar '18

#12712: break011 is broken on Windows -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Test Suite | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: break011 | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The `break011` testcase fails on Windows with some unexpected differences in stdout. {{{ +++ ./ghci.debugger/scripts/break011.run/break011.run.stdout.normalised 2016-10-16 01:57:26.489544400 +0000 @@ -51,6 +51,9 @@ "foo" "CallStack (from HasCallStack): error, called at Test7.hs:<line>:<column> in <package-id>:Main") -*** Exception: foo -CallStack (from HasCallStack): - error, called at Test7.hs:<line>:<column> in <package-id>:Main +Stopped in <exception thrown>, <unknown> +_exception :: e = SomeException + (ErrorCallWithLocation + "foo" + "CallStack (from HasCallStack): + error, called at Test7.hs:<line>:<column> in <package-id>:Main") }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12712> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13443: Typeclass resolution errors quite puzzling
by GHC 19 Mar '18

19 Mar '18

#13443: Typeclass resolution errors quite puzzling -------------------------------------+------------------------------------- Reporter: tomjaguarpaw | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 (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: -------------------------------------+------------------------------------- This ticket is based on a post I made to haskell-cafe: https://mail.haskell.org/pipermail/haskell-cafe/2016-August/124622.html Here's a program with an odd error message (GHC 8.0.1): {{{ data A a = A a deriving Eq data B = B main :: IO () main = print (A B == A B) test/main.hs:5:15: error: • No instance for (Eq B) arising from a use of ‘==’ • In the first argument of ‘print’, namely ‘(A B == A B)’ In the expression: print (A B == A B) In an equation for ‘main’: main = print (A B == A B) }}} I get an error about `Eq B` even though it's `Eq A` that is manifestly required at the call site. This error is odder when `A` and `B` are defined far away from the use of `==`. This is even odder: {{{ data A a = A a data B = B instance Ord a => Eq (A a) where main :: IO () main = print (A B == A B) test/main.hs:7:15: error: • No instance for (Ord B) arising from a use of ‘==’ • In the first argument of ‘print’, namely ‘(A B == A B)’ In the expression: print (A B == A B) In an equation for ‘main’: main = print (A B == A B) }}} Now not only is the type puzzling (`B` instead of `A`) but the *class* is puzzling (`Ord` instead of `Eq`). This occurred to me in practice because `Data.Graph.Inductive.PatriciaTree.Gr` has `(Eq a, Ord b) => Eq (Gr a b)`. It would have been a lot more helpful to see {{{ * No instance for (Ord B) * arising from (Eq A) * arising from the use of '==' }}} Does anyone agree with me that GHC should produce the full trace when it fails to resolve instances rather than just the proximal failure? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13443> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12193: Include target versions of unlit and hsc2hs when cross-compiling
by GHC 19 Mar '18

19 Mar '18

#12193: Include target versions of unlit and hsc2hs when cross-compiling -------------------------------------+------------------------------------- Reporter: glaubitz | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | 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: -------------------------------------+------------------------------------- Hello! I have been working on getting ghc packaged on Debian for m68k and sh4. While ghc itself works without any major issues on these targets, the performance is a bit too low to just build ghc from sources on the machines itself. It works, but it may take up to three weeks or more. To workaround this problem, I am using a cross-compiled version of ghc on these platforms which works quite well. However, while using the cross- compiled Debian ghc packaged, I noticed that some packages fail to build from source because my cross-compiled version of ghc is missing the "unlit" utility. Looking at the result of the cross-compiled ghc for m68k, it's obvious why unlit is missing: {{{ glaubitz@ikarus:~/debian/ghc/ghc-8.0.1$ file ./inplace/lib/bin/* ./inplace/lib/bin/ghc-iserv: ELF 32-bit MSB executable, Motorola m68k, 68020, version 1 (SYSV), dynamically linked, interpreter /lib/ld.so.1, for GNU/Linux 3.2.0, BuildID[sha1]=39f595d60d0c596714aa0fedcc0bfa3a35921c41, not stripped ./inplace/lib/bin/ghc-iserv-prof: ELF 32-bit MSB executable, Motorola m68k, 68020, version 1 (SYSV), dynamically linked, interpreter /lib/ld.so.1, for GNU/Linux 3.2.0, BuildID[sha1]=f83f10fc7d925f54fb18816384ae91ae6c1b9ac8, not stripped ./inplace/lib/bin/ghc-pkg: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld- linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=41d534ca0e83df11274eade67477db1e9667fec5, not stripped ./inplace/lib/bin/ghc-stage1: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld- linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=089a2121e49e16ea7ba721c350b04a965b19dded, not stripped ./inplace/lib/bin/ghc-stage2: ELF 32-bit MSB executable, Motorola m68k, 68020, version 1 (SYSV), dynamically linked, interpreter /lib/ld.so.1, for GNU/Linux 3.2.0, BuildID[sha1]=589cdca9242bd132e1c80736a79ebf4209eb1c78, not stripped ./inplace/lib/bin/hpc: ELF 32-bit MSB executable, Motorola m68k, 68020, version 1 (SYSV), dynamically linked, interpreter /lib/ld.so.1, for GNU/Linux 3.2.0, BuildID[sha1]=f401ba499a4cf865def36a7dc6d7c3a32385c85f, not stripped ./inplace/lib/bin/hsc2hs: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld- linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=a532a7cc6f0c1e95e7c66aab2b4c53e1d0b58d88, not stripped ./inplace/lib/bin/unlit: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld- linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=30ab37170ddcb09bcb7885ae3c18a353f6d128b7, not stripped glaubitz@ikarus:~/debian/ghc/ghc-8.0.1$ }}} Thus, both "unlit" and "hsc2hs" are not built for the target architecture when cross-compiling. After a quick look at utils/unlit/ghc.mk, it becomes obvious why that's the case: {{{ $(eval $(call build-prog,utils/unlit,dist,0)) }}} Would it be possible to change the build configuration such that "unlit" and "hsc2hs" are built for the target as well when cross-compiling? That would be great :). Adrian [1] [https://buildd.debian.org/status/fetch.php?pkg=haskell- fmlist&arch=m68k&ver=0.9-4&stamp=1465990971] -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12193> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12038: Shutdown interacts badly with requestSync()
by GHC 19 Mar '18

19 Mar '18

#12038: Shutdown interacts badly with requestSync() -------------------------------------+------------------------------------- Reporter: simonmar | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Runtime | Version: 7.10.3 System | 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: -------------------------------------+------------------------------------- -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12038> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12715: T3994 is intermittently broken on Windows
by GHC 19 Mar '18

19 Mar '18

#12715: T3994 is intermittently broken on Windows --------------------------------------+--------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Test Suite | Version: 8.1 Keywords: | Operating System: Windows Architecture: x86_64 (amd64) | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------------+--------------------------------- The `T3994` testcase sometimes appears to crash on Windows, {{{ +++ ../../libraries/process/tests/T3994.run/T3994.run.stderr.normalised 2016-10-16 03:11:54.601205700 +0000 @@ -0,0 +1,2 @@ + 1521 [main] sh 5272 child_copy: cygheap read copy failed, 0x1802FE408..0x180307A08, done 0, windows pid 5272, Win32 error 299 + 7952 [main] sh 5272 C:/msys64/usr/bin/sh: *** fatal error in forked process - ccalloc would have returned NULL }}} This very well may be an msys issue. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12715> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12737: T12227 is failing on ghc-8.0
by GHC 19 Mar '18

19 Mar '18

#12737: T12227 is failing on ghc-8.0 -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.2 Component: Visual | Version: 8.0.1 Haskell | 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: -------------------------------------+------------------------------------- Fresh validate from 5eab189b329344630f76b8751c1289ce480ca46b on x86_64 Linux: {{{ =====> T12227(normal) 1 of 1 [0, 0, 0] cd ./perf/compiler && "/home/hs01/ezyang/ghc-validate/inplace/test spaces/ghc-stage2" -c T12227.hs -fforce-recomp -dno-debug-output -fshow- warning-groups -no-user-package-db -rtsopts -fno-warn-tabs -fno-warn- missed-specialisations -fno-ghci-history -O2 -ddump-hi -ddump-to-file +RTS -M1G +RTS -V0 -tT12227.comp.stats --machine-readable -RTS > T12227.comp.stderr 2>&1 bytes allocated value is too high: Expected T12227(normal) bytes allocated: 1822822016 +/-5% Lower bound T12227(normal) bytes allocated: 1731680915 Upper bound T12227(normal) bytes allocated: 1913963117 Actual T12227(normal) bytes allocated: 9256914200 Deviation T12227(normal) bytes allocated: 407.8 % *** unexpected stat test failure for T12227(normal) }}} That's a pretty awful regression, if it is real. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12737> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12619: Allow users guide to be built independently from GHC
by GHC 19 Mar '18

19 Mar '18

#12619: Allow users guide to be built independently from GHC -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Compiler | 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: -------------------------------------+------------------------------------- At HIW 2016 it was suggested that this would greatly reduce the friction to contributing users guide fixes. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12619> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12389: Limit duplicate export warnings for datatypes
by GHC 19 Mar '18

19 Mar '18

#12389: Limit duplicate export warnings for datatypes -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: Type: feature | Status: new request | Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 7.10.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Incorrect Unknown/Multiple | warning at compile-time Test Case: | Blocked By: Blocking: | Related Tickets: #11959 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- `containers` sometimes exports data constructors/patterns conditionally (depending on GHC version and whether `TESTING` is defined). Presently, to avoid a duplicate export warning, it's necessary to write a separate export line for each combination of exported constructors, which is horrible: {{{#!hs module Foo ( #ifdef TESTING #ifdef USE_PATTERN_SYNONYMS Foo (Foo, Pat1, Pat2) #else Foo (Foo) #endif #elif USE_PATTERN_SYNONYMS Foo (Pat1, Pat2) #else Foo #endif }}} or to break up the lines with CPP, which is so horrible I can't even bring myself to write it. I'd much rather be able to write {{{#!hs module Foo ( Foo #ifdef TESTING ,Foo(Foo) #endif #ifdef USE_PATTERN_SYNONYMS ,Foo(Pat1, Pat2) #endif ) }}} The trouble here is that GHC warns about duplicate export of the type `Foo`. I think there's a pretty simple partial solution: only warn about a type export that is *completely* redundant, adding neither type constructor nor pattern. And offer a way to turn off the redundant export warning entirely for types and classes without turning it off for bindings. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12389> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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