December 2014 - ghc-tickets

[GHC] #8853: Alarming looking warning about non-exhaustive pattern
by GHC 03 May '18

03 May '18

#8853: Alarming looking warning about non-exhaustive pattern -------------------------+------------------------------------------------- Reporter: | Owner: MikolajKonarski | Status: new Type: bug | Milestone: Priority: | Version: 7.8.1-rc2 normal | Operating System: Linux Component: | Type of failure: Incorrect warning at Compiler | compile-time Keywords: | Test Case: Architecture: | Blocking: x86_64 (amd64) | Difficulty: | Unknown | Blocked By: | Related Tickets: | -------------------------+------------------------------------------------- The attached code produces this alarming warning: ~/waste$ ghc --version The Glorious Glasgow Haskell Compilation System, version 7.8.0.20140228 ~/waste$ ghc -Wall --make AlarmingPattern.hs -fforce-recomp [1 of 1] Compiling Main ( AlarmingPattern.hs, AlarmingPattern.o ) AlarmingPattern.hs:6:7: Warning: Pattern match(es) are non-exhaustive In an equation for ‘takeFromInv’: Patterns not matched: (GHC.Types.I# _) (GHC.Types.I# (#x)) with #x `notElem` [0#] Linking AlarmingPattern ... ~/waste$ ./AlarmingPattern AlarmingPattern: AlarmingPattern.hs:(6,7)-(7,26): Non-exhaustive patterns in function takeFromInv -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8853> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8494: Warn if a pattern guard obviates all others
by GHC 03 May '18

03 May '18

#8494: Warn if a pattern guard obviates all others -------------------------+------------------------------------------------- Reporter: | Owner: JohnWiegley | Status: new Type: | Milestone: feature request | Version: 7.6.3 Priority: | Operating System: Unknown/Multiple normal | Type of failure: Incorrect warning at Component: | compile-time Compiler | Test Case: Keywords: | Blocking: Architecture: | Unknown/Multiple | Difficulty: | Unknown | Blocked By: | Related Tickets: | -------------------------+------------------------------------------------- The following code, when compiled with `-Wall`, gives no warnings: {{{ module Main where main :: IO () main = print $ foo (10 :: Int) where foo x | True = (20 :: Int) | x == 10 = (30 :: Int) }}} I would expect that since the pattern guard `| True` obviates the following guards, that it would warn about unreachable code. There was a bug in my code today which I tracked down to a code transposition that would have been easily spotted with such a warning. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8494> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8406: Invalid object in isRetainer() or Segfault
by GHC 25 Apr '18

25 Apr '18

#8406: Invalid object in isRetainer() or Segfault ----------------------------------+---------------------------------- Reporter: crockeea | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: Runtime crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+---------------------------------- When compiling with -rtsopts -threaded -prof -fprof-auto -caf-all and running with -N4 -hr I get a "Segmentation fault" every time. If I run with -N4 -qg1 -hr, I either get a segfault or internal error: Invalid object in isRetainer(): 40 When the segfault happens, it happens quickly. If the segfault doesn't happen, the program runs for about 5 seconds and I get "invalid object" error (always 40). Without -hr, I have never gotten a segfault. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8406> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9678: Warning about __sync_fetch_and_nand semantics from gcc
by GHC 24 Apr '18

24 Apr '18

#9678: Warning about __sync_fetch_and_nand semantics from gcc -------------------------------------+------------------------------------- Reporter: gintas | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Build System | Version: 7.9 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- When building ghc, I'm getting warnings about __sync_fetch_and_nand that the semantics have changed for gcc 4.4+. I'm building on Windows, but I don't think that matters. Is this an indication of a problem or does that warning just need to be silenced? I ran the build with gcc 4.8.3: $ inplace/mingw/bin/gcc -v Using built-in specs. COLLECT_GCC=C:\msys64\home\Gintas\ghc\inplace\mingw\bin\gcc.exe COLLECT_LTO_WRAPPER=C:/msys64/home/Gintas/ghc/inplace/mingw/bin/../libexec/gcc/x86_64-w64-mingw32/4.8.3 /lto-wrapper.exe Target: x86_64-w64-mingw32 Configured with: ../../../src/gcc-4.8.3/configure --host=x86_64-w64-mingw32 --build=x86_64-w64-mingw32 --target=x86_64-w64-mingw32 --prefix=/mingw64 --with- sysroot=/c/mingw483/x86_64-483-posix-seh-rt_v3-rev0/mingw64 --with-gxx- include-dir=/mingw64/x86_64-w64-mingw32/include/c++ --enable-shared --enable-static --disable-multilib --enable- languages=ada,c,c++,fortran,objc,obj-c++,lto --enable-libstdcxx-time=yes --enable-threads=posix --enable-libgomp --enable-lto --enable-graphite --enable-checking=release --enable-fully-dynamic-string --enable-version- specific-runtime-libs --disable-isl-version-check --disable-cloog-version- check --disable-libstdcxx-pch --disable-libstdcxx-debug --enable-bootstrap --disable-rpath --disable-win32-registry --disable-nls --disable-werror --disable-symvers --with-gnu-as --with-gnu-ld --with-arch=nocona --with- tune=core2 --with-libiconv --with-system-zlib --with- gmp=/c/mingw483/prerequisites/x86_64-w64-mingw32-static --with- mpfr=/c/mingw483/prerequisites/x86_64-w64-mingw32-static --with- mpc=/c/mingw483/prerequisites/x86_64-w64-mingw32-static --with- isl=/c/mingw483/prerequisites/x86_64-w64-mingw32-static --with- cloog=/c/mingw483/prerequisites/x86_64-w64-mingw32-static --enable-cloog- backend=isl --with-pkgversion='x86_64-posix-seh-rev0, Built by MinGW-W64 project' --with-bugurl=http://sourceforge.net/projects/mingw-w64 CFLAGS='-O2 -pipe -I/c/mingw483/x86_64-483-posix-seh- rt_v3-rev0/mingw64/opt/include -I/c/mingw483/prerequisites/x86_64-zlib- static/include -I/c/mingw483/prerequisites/x86_64-w64-mingw32-static/include' CXXFLAGS='-O2 -pipe -I/c/mingw483/x86_64-483-posix-seh- rt_v3-rev0/mingw64/opt/include -I/c/mingw483/prerequisites/x86_64-zlib- static/include -I/c/mingw483/prerequisites/x86_64-w64-mingw32-static/include' CPPFLAGS= LDFLAGS='-pipe -L/c/mingw483/x86_64-483-posix-seh- rt_v3-rev0/mingw64/opt/lib -L/c/mingw483/prerequisites/x86_64-zlib- static/lib -L/c/mingw483/prerequisites/x86_64-w64-mingw32-static/lib' Thread model: posix gcc version 4.8.3 (x86_64-posix-seh-rev0, Built by MinGW-W64 project) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9678> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9074: GHC 7.8.2's ghci does not track missing symbols when loading non-Haskell object files
by GHC 17 Apr '18

17 Apr '18

#9074: GHC 7.8.2's ghci does not track missing symbols when loading non-Haskell object files ------------------------------------+------------------------------------- Reporter: massysett | 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: | ------------------------------------+------------------------------------- I have a package that bundles in C library sources. I never had a problem with this when using GHC 7.6. In GHC 7.8, the order of the c-sources in the cabal file now matters. Sources must be listed earlier if they have symbols that subsequently loaded object files will need. If the c-sources are in the wrong order, when running "cabal repl" I get Loading object (static) dist/build/decnumber/src/decQuad.o ... ghc: panic! (the 'impossible' happened) (GHC version 7.8.2 for x86_64-unknown-linux): Loading temp shared object failed: /tmp/ghc14294_0/ghc14294_1.so: undefined symbol: DECSTICKYTAB Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug When using the same code and cabal file with GHC 7.6, "cabal repl" works fine: GHCi loads each static object (regardless of ordering in the cabal file), links up the necessary symbols, and launches successfully. Haskell Cafe discussion here: http://www.haskell.org/pipermail/haskell-cafe/2014-May/114041.html -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9074> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9307: wave4main in nofib fails
by GHC 14 Apr '18

14 Apr '18

#9307: wave4main in nofib fails -------------------------------------+------------------------------------- Reporter: jrp | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.10.1 Component: NoFib benchmark | Version: 7.8.3 suite | Operating System: MacOS X Keywords: wave4main | Type of failure: Incorrect result Architecture: x86_64 (amd64) | at runtime Difficulty: Unknown | Test Case: wave4main Blocked By: | Blocking: Related Tickets: | -------------------------------------+------------------------------------- Compiling HEAD with perf-llvm, (3.4.2) and running the nofib suite fails at the wave4main case. It is not clear to me whether wave4main should always produce the same output (and so the test fails because it does not do so) or whether the numbers generated depend on some feature of the build settings, or OS. {{{ HC = /Users/xxx/Projects/ghc/inplace/bin/ghc-stage2 HC_OPTS = -O2 -Rghc-timing -H32m -hisuf hi -cpp -fglasgow-exts -rtsopts RUNTEST_OPTS = -ghc-timing ==nofib== wave4main: size of wave4main follows... __TEXT __DATA __OBJC others dec hex 4091904 450560 0 4295947176 4300489640 1005443a8 ==nofib== wave4main: time to run wave4main follows... ../../../runstdtest/runstdtest ./wave4main -o1 wave4main.stdout -o1 wave4main.stdout2 -o1 wave4main.stdout3 -o1 wave4main.stdout -o1 wave4main.stdout2 -o1 wave4main.stdout3 -ghc-timing 4000; ../../../runstdtest/runstdtest ./wave4main -o1 wave4main.stdout -o1 wave4main.stdout2 -o1 wave4main.stdout3 -o1 wave4main.stdout -o1 wave4main.stdout2 -o1 wave4main.stdout3 -ghc-timing 4000; ../../../runstdtest/runstdtest ./wave4main -o1 wave4main.stdout -o1 wave4main.stdout2 -o1 wave4main.stdout3 -o1 wave4main.stdout -o1 wave4main.stdout2 -o1 wave4main.stdout3 -ghc-timing 4000; ../../../runstdtest/runstdtest ./wave4main -o1 wave4main.stdout -o1 wave4main.stdout2 -o1 wave4main.stdout3 -o1 wave4main.stdout -o1 wave4main.stdout2 -o1 wave4main.stdout3 -ghc-timing 4000; ../../../runstdtest/runstdtest ./wave4main -o1 wave4main.stdout -o1 wave4main.stdout2 -o1 wave4main.stdout3 -o1 wave4main.stdout -o1 wave4main.stdout2 -o1 wave4main.stdout3 -ghc-timing 4000; real 0m0.217s user 0m0.191s sys 0m0.011s ././wave4main 4000 < /dev/null expected stdout not matched by reality --- wave4main.stdout 2014-07-08 20:57:14.000000000 +0100 +++ /var/folders/d9/94xh7l810mz3_skcsfh68khh0000gn/T//runtest16932.1 2014-07-13 13:43:22.000000000 +0100 @@ -1 +1 @@ -69923/1465 +69096/1465 real 0m0.197s user 0m0.186s sys 0m0.008s ././wave4main 4000 < /dev/null expected stdout not matched by reality --- wave4main.stdout 2014-07-08 20:57:14.000000000 +0100 +++ /var/folders/d9/94xh7l810mz3_skcsfh68khh0000gn/T//runtest16961.1 2014-07-13 13:43:22.000000000 +0100 @@ -1 +1 @@ -69923/1465 +69096/1465 real 0m0.201s user 0m0.189s sys 0m0.009s ././wave4main 4000 < /dev/null expected stdout not matched by reality --- wave4main.stdout 2014-07-08 20:57:14.000000000 +0100 +++ /var/folders/d9/94xh7l810mz3_skcsfh68khh0000gn/T//runtest17011.1 2014-07-13 13:43:22.000000000 +0100 @@ -1 +1 @@ -69923/1465 +69096/1465 real 0m0.201s user 0m0.190s sys 0m0.008s ././wave4main 4000 < /dev/null expected stdout not matched by reality --- wave4main.stdout 2014-07-08 20:57:14.000000000 +0100 +++ /var/folders/d9/94xh7l810mz3_skcsfh68khh0000gn/T//runtest17051.1 2014-07-13 13:43:23.000000000 +0100 @@ -1 +1 @@ -69923/1465 +69096/1465 real 0m0.200s user 0m0.189s sys 0m0.009s ././wave4main 4000 < /dev/null expected stdout not matched by reality --- wave4main.stdout 2014-07-08 20:57:14.000000000 +0100 +++ /var/folders/d9/94xh7l810mz3_skcsfh68khh0000gn/T//runtest17080.1 2014-07-13 13:43:23.000000000 +0100 @@ -1 +1 @@ -69923/1465 +69096/1465 make: *** [runtests] Error 1 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9307> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8165: Use GeneralizedNewtypeDeriving to automatically create associated type families
by GHC 12 Apr '18

12 Apr '18

#8165: Use GeneralizedNewtypeDeriving to automatically create associated type families ------------------------------------+------------------------------------- Reporter: MikeIzbicki | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Here's a simple example: {{{ class C a where type T a instance C Int where type T Int = Bool newtype NT = NT Int deriving C }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8165> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8118: <stdout>: commitAndReleaseBuffer: invalid argument (invalid character)
by GHC 10 Apr '18

10 Apr '18

#8118: <stdout>: commitAndReleaseBuffer: invalid argument (invalid character) ----------------------------------+---------------------------------- Reporter: guest | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: OpenBSD Architecture: x86_64 (amd64) | Type of failure: Runtime crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+---------------------------------- I get the following error... {{{ <stdout>: commitAndReleaseBuffer: invalid argument (invalid character) }}} When running following program: {{{#!haskell {-# LANGUAGE OverloadedStrings #-} import qualified Data.Text as T import qualified Data.Text.IO as T main = T.putStrLn "čušpajž日本語" }}} Was tested in #haskell and I have all the UTF-8 Settings set and so forth. It compiles just fine, but crashes during runtime. gcc -v: {{{ Reading specs from /usr/lib/gcc-lib/amd64-unknown-openbsd5.4/4.2.1/specs Target: amd64-unknown-openbsd5.4 Configured with: OpenBSD/amd64 system compiler Thread model: posix gcc version 4.2.1 20070719 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8118> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9406: unexpected failure for T7837(profasm)
by GHC 29 Mar '18

29 Mar '18

#9406: unexpected failure for T7837(profasm) -------------------------------------+------------------------------------- Reporter: jrp | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Test Suite | Version: 7.8.3 Keywords: T7837 | Operating System: MacOS X Architecture: x86_64 (amd64) | Type of failure: Incorrect Difficulty: Unknown | result at runtime Blocked By: | Test Case: T7837 Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- This may be a test suite configuration error as the normal case works. When run with an llvm-perf build of the HEAD, I get: {{{ =====> T7837(normal) 1395 of 4068 [0, 0, 0] cd ./indexed-types/should_compile && '/Users/jrp/Projects/haskell/ghc/inplace/bin/ghc-stage2' -fforce-recomp -dcore-lint -dcmm-lint -dno-debug-output -no-user-package-db -rtsopts -fno-ghci-history -c T7837.hs -O -ddump-rule-firings >T7837.comp.stderr 2>&1 =====> T7837(profasm) 1395 of 4068 [0, 0, 0] cd ./indexed-types/should_compile && '/Users/jrp/Projects/haskell/ghc/inplace/bin/ghc-stage2' -fforce-recomp -dcore-lint -dcmm-lint -dno-debug-output -no-user-package-db -rtsopts -fno-ghci-history -c T7837.hs -O -prof -static -auto-all -O -ddump-rule- firings >T7837.comp.stderr 2>&1 Actual stderr output differs from expected: --- ./indexed-types/should_compile/T7837.stderr 2014-08-03 11:36:53.000000000 +0100 +++ ./indexed-types/should_compile/T7837.comp.stderr 2014-08-04 23:16:34.000000000 +0100 @@ -1,3 +1,4 @@ Rule fired: Class op abs Rule fired: Class op signum Rule fired: normalize/Double +Rule fired: Class op / *** unexpected failure for T7837(profasm) Unexpected results from: TEST="T7837" OVERALL SUMMARY for test run started at Mon Aug 4 23:16:32 2014 BST 0:00:02 spent to go through 4068 total tests, which gave rise to 19536 test cases, of which 19534 were skipped 0 had missing libraries 1 expected passes 0 expected failures 0 caused framework failures 0 unexpected passes 1 unexpected failures Unexpected failures: indexed-types/should_compile T7837 [stderr mismatch] (profasm) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9406> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9671: Allow expressions in patterns
by GHC 16 Mar '18

16 Mar '18

#9671: Allow expressions in patterns -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.10.1 Component: Compiler | Version: Keywords: patterns, pattern | Operating System: synonyms | Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: Difficulty: Unknown | None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- I've outlined a proposal for extending pattern synonyms to depend on terms (PatternFamilies), the name is less than ideal but I'll keep the page under that name for now. The proposal's introduction has been rewritten. The simplest use case are patterns that matches only when a set contains an element (`IsMember`) or when a set does not contain an element (`NotMember`): [[Image(wiki:PatternFamilies:member.png)]] {{{#!hs hasKeys :: Set Item -> IO () hasKeys (IsMember "keys") = leaveHouse hasKeys (NotMember "keys") = findKeys >> leaveHouse }}} or a pattern that matches a map if the key exists: [[Image(wiki:PatternFamilies:lookup.png)]] used like this: {{{#!hs age :: Map Person Age -> String age (Lookup "Alice" 60) = "Alice is 60 years old!" age (Lookup "Alice" age) = "Alice is " ++ show age ++ "." age (Lookup "Bob" _) = "No info on Alice but we know how old Bob is." age _ = "..." }}} Further details and examples can be found here: PatternFamilies, I discussed it with several people ICFP 2014. This would not require a new extension but would extend PatternSynonyms. This feature can be quite useful, especially when working with deeply nested structures (ASTs, JSON, XML, ...). If people are fine with it I will implement it. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9671> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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