August 2014 - ghc-tickets

[GHC] #9348: "Symbol not found" when using a shared library
by GHC 15 Dec '15

15 Dec '15

#9348: "Symbol not found" when using a shared library -----------------------------------+----------------------------------- Reporter: alex.davis | Owner: simonmar Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 7.8.3 Keywords: | Differential Revisions: Operating System: MacOS X | Architecture: x86 Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -----------------------------------+----------------------------------- I'm trying to make a shared library from a simple program. It works fine on my Windows box, but gives an error on Mac OS X. Furthermore, the error seems to be generated from one of GHC's shared libraries. What happens is this. I compile my shared library with GHC, which works fine. But when I try to use it from another program (specifically, R), I get an error message containing the following: Symbol not found: _stg_IND_STATIC_info Referenced from: /usr/local/lib/ghc-7.8.3/ghc-prim-0.3.1.0/libHSghc- prim-0.3.1.0-ghc7.8.3.dylib Expected in: flat namespace in /usr/local/lib/ghc-7.8.3/ghc-prim-0.3.1.0/libHSghc- prim-0.3.1.0-ghc7.8.3.dylib More details: The program I'm trying to use is R. In R, you load a shared library with the command "dyn.load". When I try this, the command I use is "dyn.load('final.dylib')", and the full error message is what follows: --- Error in dyn.load("final.dylib") : unable to load shared object '/Users/alexanderdavis/Desktop/illustrate bug copy/final.dylib': dlopen(/Users/alexanderdavis/Desktop/illustrate bug copy/final.dylib, 6): Symbol not found: _stg_IND_STATIC_info Referenced from: /usr/local/lib/ghc-7.8.3/ghc-prim-0.3.1.0/libHSghc- prim-0.3.1.0-ghc7.8.3.dylib Expected in: flat namespace in /usr/local/lib/ghc-7.8.3/ghc-prim-0.3.1.0/libHSghc- prim-0.3.1.0-ghc7.8.3.dylib --- As I said, I have done all of this with no trouble on Windows. I compiled into a DLL, loaded the program into R, and was able to use the functions in it. My Mac OS version is 10.9.4. My R version is 3.0.2. When loaded, it displays "Platform: x86_64-apple- darwin10.8.0 (64-bit)", but Sys.getev("R_ARCH") returns the empty string. Command used for compiler: ghc --make -dynamic -fPIC -shared SumRoots.hs StartEnd.c -o final.dylib The code is attached. It is from a blog post by Neil Mitchelll (author of HLint) about calling Haskell from R: http://neilmitchell.blogspot.com/2011/10/calling-haskell-from-r.html -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9348> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9378: Make unknown LANGUAGE pragmas a warning, not an error
by GHC 15 Dec '15

15 Dec '15

#9378: Make unknown LANGUAGE pragmas a warning, not an error -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Currently, if I say `{-# LANGUAGE Foo #-}` at the top of my file, it fails to compile. This failure seems unnecessary, especially because any new language feature `Foo` enables will fail to compile later on down the file. Is it possible to have a "stern warning" that is produced even when other parts of the file produce errors? The reason I'm bringing this up is that, when 7.8 came out with its role annotations, users needed CPP in two different places: both to protect the `RoleAnnotations` pragma and to protect the role annotations themselves. This may be unavoidable on the role annotations directly, but I think we can improve the situation around `LANGUAGE` pragmas. Is there a downside to this? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9378> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9499: Add -prelude-is flag
by GHC 15 Dec '15

15 Dec '15

#9499: Add -prelude-is flag -------------------------------------+------------------------------------- Reporter: agibiansky | Owner: agibiansky Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.9 Keywords: flag | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Easy (less than 1 | Type of failure: hour) | None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- I would like GHC to have a `-prelude-is` flag, which would specify an alternate Prelude to use instead of the default Haskell prelude. The benefit this would have is that this would give alternate preludes a more first-class status. Instead of having to import an alternative prelude everywhere, you could just have a ghc-options: -prelude-is=... flag in your *.cabal file, and have a different prelude be used. This is important for my own work, as I highly prefer other preludes for my non- library development; I think this is a feature which will be very useful as Haskell develops and we try to figure out how to get rid of the warts in the current Prelude. Additional discussion here: https://groups.google.com/forum/#!topic /haskell-cafe/NCVzXZcxNmQ -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9499> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8294: T7478 fails on Mac OS X with "unexpected bindingNone" from ld
by GHC 15 Dec '15

15 Dec '15

#8294: T7478 fails on Mac OS X with "unexpected bindingNone" from ld -----------------------------------+--------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: GHC API | Version: 7.7 Keywords: | Operating System: MacOS X Architecture: | Type of failure: Compile-time crash Unknown/Multiple | Test Case: T7478 Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | -----------------------------------+--------------------------------------- (Tangentially, the test script was swallowing up relevant output; you need to get rid of the output hook to see any debugging output from GHC proper). Linker step fails: {{{ *** Linker: /usr/bin/gcc -m64 -fno-stack-protector -DTABLES_NEXT_TO_CODE -m64 -v -o A -Wl,-no_compact_unwind C.o -L/Users/ezyang/Dev/ghc-init/libraries/base /dist-install/build -L/Users/ezyang/Dev/ghc-init/libraries/integer-gmp /dist-install/build -L/Users/ezyang/Dev/ghc-init/libraries/ghc-prim/dist- install/build -L/Users/ezyang/Dev/ghc-init/rts/dist/build /var/folders/l8/1lth36c11yg8dv_3kz779_th0000gn/T/ghc26290_0/ghc26290_10.o -lHSbase-4.7.0.0-ghc7.7.20130913 -lHSinteger-gmp-0.5.1.0-ghc7.7.20130913 -lHSghc-prim-0.3.1.0-ghc7.7.20130913 -lHSrts-ghc7.7.20130913 -lffi -liconv -lm -ldl -Wl,-u,_ghczmprim_GHCziTypes_Izh_static_info -Wl,-u,_ghczmprim_GHCziTypes_Czh_static_info -Wl,-u,_ghczmprim_GHCziTypes_Fzh_static_info -Wl,-u,_ghczmprim_GHCziTypes_Dzh_static_info -Wl,-u,_base_GHCziPtr_Ptr_static_info -Wl,-u,_ghczmprim_GHCziTypes_Wzh_static_info -Wl,-u,_base_GHCziInt_I8zh_static_info -Wl,-u,_base_GHCziInt_I16zh_static_info -Wl,-u,_base_GHCziInt_I32zh_static_info -Wl,-u,_base_GHCziInt_I64zh_static_info -Wl,-u,_base_GHCziWord_W8zh_static_info -Wl,-u,_base_GHCziWord_W16zh_static_info -Wl,-u,_base_GHCziWord_W32zh_static_info -Wl,-u,_base_GHCziWord_W64zh_static_info -Wl,-u,_base_GHCziStable_StablePtr_static_info -Wl,-u,_ghczmprim_GHCziTypes_Izh_con_info -Wl,-u,_ghczmprim_GHCziTypes_Czh_con_info -Wl,-u,_ghczmprim_GHCziTypes_Fzh_con_info -Wl,-u,_ghczmprim_GHCziTypes_Dzh_con_info -Wl,-u,_base_GHCziPtr_Ptr_con_info -Wl,-u,_base_GHCziPtr_FunPtr_con_info -Wl,-u,_base_GHCziStable_StablePtr_con_info -Wl,-u,_ghczmprim_GHCziTypes_False_closure -Wl,-u,_ghczmprim_GHCziTypes_True_closure -Wl,-u,_base_GHCziPack_unpackCString_closure -Wl,-u,_base_GHCziIOziException_stackOverflow_closure -Wl,-u,_base_GHCziIOziException_heapOverflow_closure -Wl,-u,_base_ControlziExceptionziBase_nonTermination_closure -Wl,-u,_base_GHCziIOziException_blockedIndefinitelyOnMVar_closure -Wl,-u,_base_GHCziIOziException_blockedIndefinitelyOnSTM_closure -Wl,-u,_base_ControlziExceptionziBase_nestedAtomically_closure -Wl,-u,_base_GHCziWeak_runFinalizzerBatch_closure -Wl,-u,_base_GHCziTopHandler_flushStdHandles_closure -Wl,-u,_base_GHCziTopHandler_runIO_closure -Wl,-u,_base_GHCziTopHandler_runNonIO_closure -Wl,-u,_base_GHCziConcziIO_ensureIOManagerIsRunning_closure -Wl,-u,_base_GHCziConcziIO_ioManagerCapabilitiesChanged_closure -Wl,-u,_base_GHCziConcziSync_runSparks_closure -Wl,-u,_base_GHCziConcziSignal_runHandlers_closure -Wl,-search_paths_first Using built-in specs. Target: i686-apple-darwin11 Configured with: /private/var/tmp/llvmgcc42/llvmgcc42-2336.11~182/src/configure --disable- checking --enable-werror --prefix=/Applications/Xcode.app/Contents/Developer/usr/llvm-gcc-4.2 --mandir=/share/man --enable-languages=c,objc,c++,obj-c++ --program- prefix=llvm- --program-transform-name=/^[cg][^.-]*$/s/$/-4.2/ --with- slibdir=/usr/lib --build=i686-apple-darwin11 --enable- llvm=/private/var/tmp/llvmgcc42/llvmgcc42-2336.11~182/dst- llvmCore/Developer/usr/local --program-prefix=i686-apple-darwin11- --host=x86_64-apple-darwin11 --target=i686-apple-darwin11 --with-gxx- include-dir=/usr/include/c++/4.2.1 Thread model: posix gcc version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00) /usr/llvm-gcc-4.2/bin/../libexec/gcc/i686-apple-darwin11/4.2.1/collect2 -dynamic -arch x86_64 -macosx_version_min 10.8.3 -weak_reference_mismatches non-weak -o A -lcrt1.10.6.o -L/Users/ezyang/Dev /ghc-init/libraries/base/dist-install/build -L/Users/ezyang/Dev/ghc- init/libraries/integer-gmp/dist-install/build -L/Users/ezyang/Dev/ghc- init/libraries/ghc-prim/dist-install/build -L/Users/ezyang/Dev/ghc- init/rts/dist/build -L/usr/llvm-gcc-4.2/bin/../lib/gcc/i686-apple- darwin11/4.2.1/x86_64 -L/Applications/Xcode.app/Contents/Developer/usr /llvm-gcc-4.2/lib/gcc/i686-apple-darwin11/4.2.1/x86_64 -L/usr/llvm- gcc-4.2/bin/../lib/gcc/i686-apple-darwin11/4.2.1 -L/usr/llvm- gcc-4.2/bin/../lib/gcc -L/Applications/Xcode.app/Contents/Developer/usr /llvm-gcc-4.2/lib/gcc/i686-apple-darwin11/4.2.1 -L/usr/llvm- gcc-4.2/bin/../lib/gcc/i686-apple-darwin11/4.2.1/../../.. -L/Applications/Xcode.app/Contents/Developer/usr/llvm-gcc-4.2/lib/gcc/i686 -apple-darwin11/4.2.1/../../.. -no_compact_unwind C.o /var/folders/l8/1lth36c11yg8dv_3kz779_th0000gn/T/ghc26290_0/ghc26290_10.o -lHSbase-4.7.0.0-ghc7.7.20130913 -lHSinteger-gmp-0.5.1.0-ghc7.7.20130913 -lHSghc-prim-0.3.1.0-ghc7.7.20130913 -lHSrts-ghc7.7.20130913 -lffi -liconv -lm -ldl -u _ghczmprim_GHCziTypes_Izh_static_info -u _ghczmprim_GHCziTypes_Czh_static_info -u _ghczmprim_GHCziTypes_Fzh_static_info -u _ghczmprim_GHCziTypes_Dzh_static_info -u _base_GHCziPtr_Ptr_static_info -u _ghczmprim_GHCziTypes_Wzh_static_info -u _base_GHCziInt_I8zh_static_info -u _base_GHCziInt_I16zh_static_info -u _base_GHCziInt_I32zh_static_info -u _base_GHCziInt_I64zh_static_info -u _base_GHCziWord_W8zh_static_info -u _base_GHCziWord_W16zh_static_info -u _base_GHCziWord_W32zh_static_info -u _base_GHCziWord_W64zh_static_info -u _base_GHCziStable_StablePtr_static_info -u _ghczmprim_GHCziTypes_Izh_con_info -u _ghczmprim_GHCziTypes_Czh_con_info -u _ghczmprim_GHCziTypes_Fzh_con_info -u _ghczmprim_GHCziTypes_Dzh_con_info -u _base_GHCziPtr_Ptr_con_info -u _base_GHCziPtr_FunPtr_con_info -u _base_GHCziStable_StablePtr_con_info -u _ghczmprim_GHCziTypes_False_closure -u _ghczmprim_GHCziTypes_True_closure -u _base_GHCziPack_unpackCString_closure -u _base_GHCziIOziException_stackOverflow_closure -u _base_GHCziIOziException_heapOverflow_closure -u _base_ControlziExceptionziBase_nonTermination_closure -u _base_GHCziIOziException_blockedIndefinitelyOnMVar_closure -u _base_GHCziIOziException_blockedIndefinitelyOnSTM_closure -u _base_ControlziExceptionziBase_nestedAtomically_closure -u _base_GHCziWeak_runFinalizzerBatch_closure -u _base_GHCziTopHandler_flushStdHandles_closure -u _base_GHCziTopHandler_runIO_closure -u _base_GHCziTopHandler_runNonIO_closure -u _base_GHCziConcziIO_ensureIOManagerIsRunning_closure -u _base_GHCziConcziIO_ioManagerCapabilitiesChanged_closure -u _base_GHCziConcziSync_runSparks_closure -u _base_GHCziConcziSignal_runHandlers_closure -search_paths_first -lSystem -lgcc -lSystem ld: warning: PIE disabled. Absolute addressing (perhaps -mdynamic-no-pic) not allowed in code signed PIE, but used in _Main_main_info from C.o. To fix this warning, don't compile with -mdynamic-no-pic or link with -Wl,-no_pie final section layout: __TEXT/__text addr=0x100000D30, size=0x00000218, fileOffset=0x00000D30, type=1 __TEXT/__stubs addr=0x100000F48, size=0x0000001E, fileOffset=0x00000F48, type=27 __TEXT/__stub_helper addr=0x100000F68, size=0x00000042, fileOffset=0x00000F68, type=31 __TEXT/__eh_frame addr=0x100000FB0, size=0x00000048, fileOffset=0x00000FB0, type=18 __DATA/__program_vars addr=0x100001000, size=0x00000028, fileOffset=0x00001000, type=29 __DATA/__got addr=0x100001028, size=0x00000020, fileOffset=0x00001028, type=28 __DATA/__nl_symbol_ptr addr=0x100001048, size=0x00000010, fileOffset=0x00001048, type=28 __DATA/__la_symbol_ptr addr=0x100001058, size=0x00000028, fileOffset=0x00001058, type=26 __DATA/__data addr=0x100001080, size=0x00000040, fileOffset=0x00001080, type=0 __DATA/__const addr=0x1000010C0, size=0x00000018, fileOffset=0x000010C0, type=0 __DATA/__common addr=0x1000010D8, size=0x00000020, fileOffset=0x00000000, type=24 ld: unexpected bindingNone in '_Main_main_info' from C.o for architecture x86_64 collect2: ld returned 1 exit status T7478: T7478: phase `Linker' failed (exitcode = 1) }}} Unfortunately, I don't know what a bindingNone is... -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8294> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8566: Panic with kindFunResult
by GHC 12 Dec '15

12 Dec '15

#8566: Panic with kindFunResult ------------------------------------+------------------------------------- Reporter: dreixel | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | 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: | ------------------------------------+------------------------------------- The following program: {{{ {-# LANGUAGE DataKinds #-} {-# LANGUAGE PolyKinds #-} {-# LANGUAGE GADTs #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE TypeOperators #-} {-# LANGUAGE UndecidableInstances #-} {-# LANGUAGE MultiParamTypeClasses #-} module Bug where data U (s :: *) = forall k. AA k [U s] data I (u :: U *) (r :: [*]) :: * where A :: I (AA t as) r -- fs unused, but needs to be present for the bug class C (u :: U *) (r :: [*]) (fs :: [*]) where c :: I u r -> I u r instance (C (AA (t (I a ps)) as) ps fs) => C (AA t (a ': as)) ps fs where c A = c undefined }}} crashes a fresh copy of GHC HEAD with the following: {{{ ghc-stage2: panic! (the 'impossible' happened) (GHC version 7.7.20131126 for i386-unknown-linux): kindFunResult k1{tv a24f} [ssk] }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8566> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9017: Confusing error message with PolyKinds
by GHC 12 Dec '15

12 Dec '15

#9017: Confusing error message with PolyKinds ------------------------------------+------------------------------------- Reporter: edsko | 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: | ------------------------------------+------------------------------------- Consider the following example code: {{{ import Control.Arrow foo :: a b (m b) foo = arr return }}} if we typecheck this we rightly get two errors about missing instances (Arrow a, Monad m). However, if we enable `PolyKinds` we get the following error message: {{{ T.hs:4:7: Kind incompatibility when matching types: a0 :: * -> * -> * a :: k1 -> k -> * Expected type: a b (m b) Actual type: a0 b0 (m0 b0) Relevant bindings include foo :: a b (m b) (bound at T.hs:4:1) In the expression: arr return In an equation for ‘foo’: foo = arr return }}} I can ''sort of'' see where this is coming from if I think really hard :), so perhaps it's not a bug per se, but it's definitely confusing; and it's a pity that a type error (forgotten type qualifier) is reported as a kind error. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9017> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9389: Full Test Suite Failures
by GHC 11 Dec '15

11 Dec '15

#9389: Full Test Suite Failures ------------------------------------+---------------------------------- Reporter: jrp | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Test Suite | Version: 7.8.3 Keywords: | Operating System: MacOS X Architecture: Unknown/Multiple | Type of failure: Other Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: ------------------------------------+---------------------------------- This is just to record progress on running the full test suite on OS X for the current HEAD using a BuildFlavour = perf build. I'll check through these (some of which are configuration issues because of the non-standard build or some required libraries are not being pulled in). {{{ OVERALL SUMMARY for test run started at Thu Jul 31 23:03:39 2014 BST 0:32:31 spent to go through 4036 total tests, which gave rise to 19262 test cases, of which 4218 were skipped 358 had missing libraries 14485 expected passes 135 expected failures 0 caused framework failures 0 unexpected passes 66 unexpected failures Unexpected failures: ../../libraries/base/tests enum01 [exit code non-0] (normal,hpc,optasm,profasm,threaded1,threaded2,dyn,profthreaded,optllvm) ../../libraries/base/tests enum01 [bad stdout or stderr] (ghci) ../../libraries/base/tests enum02 [exit code non-0] (normal,hpc,optasm,profasm,threaded1,threaded2,dyn,profthreaded,optllvm) ../../libraries/base/tests enum02 [bad stdout or stderr] (ghci) ../../libraries/base/tests enum03 [exit code non-0] (normal,hpc,optasm,profasm,threaded1,threaded2,dyn,profthreaded,optllvm) ../../libraries/base/tests enum03 [bad stdout or stderr] (ghci) ../../libraries/unix/tests signals004 [bad exit code] (threaded2) concurrent/should_run T367_letnoescape [bad exit code] (optllvm) concurrent/should_run conc012 [bad exit code] (ghci) driver/objc objc-hi [bad profile] (profthreaded) driver/objc objc-hi [bad heap profile] (profasm) driver/objc objcpp-hi [bad profile] (profthreaded) driver/objc objcpp-hi [bad heap profile] (profasm) ffi/should_run ffi002 [bad exit code] (threaded2) indexed-types/should_compile T7837 [stderr mismatch] (profasm) perf/compiler T4801 [stat too good] (normal) perf/haddock haddock.base [stat not good enough] (normal) perf/should_run T9203 [stat too good] (normal) profiling/should_run callstack001 [bad stdout] (prof) quasiquotation/qq007 qq007 [exit code non-0] (profasm) quasiquotation/qq008 qq008 [exit code non-0] (profasm) rts T5435_dyn_asm [bad stdout] (normal) rts T7919 [exit code non-0] (profasm,profthreaded) rts T9078 [exit code non-0] (profasm) rts derefnull [bad profile] (profasm,profthreaded) rts divbyzero [bad profile] (profasm,profthreaded) rts overflow1 [bad exit code] (hpc,optasm,profasm,threaded2,dyn,profthreaded,optllvm) rts overflow2 [bad profile] (profasm,profthreaded) rts overflow3 [bad profile] (profasm,profthreaded) simplCore/should_compile T5550 [exit code non-0] (profasm) simplCore/should_compile T7702 [exit code non-0] (profasm) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9389> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8245: ghc-pkg list prints packages in non-alphabetical order
by GHC 07 Dec '15

07 Dec '15

#8245: ghc-pkg list prints packages in non-alphabetical order ------------------------------------+------------------------------------- Reporter: nh2 | Owner: Type: bug | 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: | ------------------------------------+------------------------------------- Instead, it prints the ones with the smallest version first. That does not make much sense. I will attach a patch. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8245> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9015: A documented way to differentiate between statements, declarations, imports, etc.
by GHC 07 Dec '15

07 Dec '15

#9015: A documented way to differentiate between statements, declarations, imports, etc. -------------------------------------+------------------------------------- Reporter: splinterofchaos | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: GHC API | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: Documentation Difficulty: Moderate (less | bug than a day) | Test Case: Blocked By: | Blocking: Related Tickets: | -------------------------------------+------------------------------------- I'm working on a little REPL and the GHC API seems to supply two functions for evaluating one line, without compiling and evaluating into an `HValue`, which doesn't seem to have an `Outputable` instace: `runStmt` and `runDecls`. As it turns out, I need slightly different code to run on declarations verses statements, so this makes sense, but given a random string from the user, how can I tell the difference? I don't see anything in the documentation about this. I took a look at ghci's source (https://github.com/ghc/ghc/blob/a6f2c852d49313fa8acea2deb3741ab86c6ef995/gh…] and it looks like they just peek at the first word of the input, and that may be correct and sufficient, but impossible to verify without looking at Haskell's grammar. But even if I did verify it, that doesn't make explicit the difference between what `runDecls` and `runStmt` will accept. For a contrived example, consider if GHC implemented a feature that allowed for a new type of decl. It might be enabled by a language extension which means that testing whether a string is a statement or declaration cannot be done purely as we have to check the dynflags. Furthermore, the client may not be aware of the extension and thus send the input to `runStmt` instead. It would seem to me that requiring the user to manually parse the input violates separation of concerns since truly GHC knows best what source GHC will accept. The user should not have to examine the input except for if they need to modify or interpret it as something other than Haskell source code. The GHC API should either document an example function for differentiating declarations from statements (and even import statements), supply one itself, or supply several along the lines of `isDecl, isStmt, isImport :: String -> Bool`. This would improve ease-of-use by making client code more obvious and correct. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9015> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8582: Record syntax for pattern synonyms
by GHC 04 Dec '15

04 Dec '15

#8582: Record syntax for pattern synonyms ------------------------------------+------------------------------------- Reporter: cactus | Owner: cactus Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: 5144 | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Implement syntax for {{{ pattern Cons{car, cdr} = (car, cdr) }}} which can then be used just like a regular record constructor, so the following are all valid patterns: {{{ Cons (Just x) [] Cons{car = Just x} }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8582> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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