July 2017 - ghc-tickets

[GHC] #13887: Template Haskell pretty-printer doesn't parenthesize infix datatype names in data declarations
by GHC 30 Jul '17

30 Jul '17

#13887: Template Haskell pretty-printer doesn't parenthesize infix datatype names in data declarations -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Template | Version: 8.0.1 Haskell | Keywords: newcomer | Operating System: Unknown/Multiple Architecture: | Type of failure: Incorrect result Unknown/Multiple | at runtime Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- If you run this program: {{{#!hs {-# LANGUAGE ExistentialQuantification #-} {-# LANGUAGE PolyKinds #-} {-# LANGUAGE TemplateHaskell #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE TypeOperators #-} module Foo where import Language.Haskell.TH main :: IO () main = do putStrLn $([d| data a :~: b where Refl1 :: a :~: a |] >>= stringE . pprint) putStrLn $([d| data a :~~: b = a ~ b => Refl2 |] >>= stringE . pprint) }}} {{{ $ /opt/ghc/8.2.1/bin/runghc Foo.hs data :~:_0 a_1 b_2 where Refl1_3 :: :~:_0 a_4 a_4 data :~~:_0 a_1 b_2 = a_1 ~ b_2 => Refl2_3 }}} It'll print the output incorrectly. Those infix names `:~:` and `:~~:` ought to be surrounded by parentheses, since they're used in prefix position. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13887> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14029: Implement the "Add <&> to Data.Functor" proposal
by GHC 29 Jul '17

29 Jul '17

#14029: Implement the "Add <&> to Data.Functor" proposal -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: task | Status: new Priority: normal | Milestone: Component: | Version: 8.0.1 libraries/base | Keywords: newcomer | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Back in August 2016, David Feuer [https://mail.haskell.org/pipermail/libraries/2016-August/027293.html proposed] adding this function (originally from `lens`) to `Data.Functor`: {{{#!hs (<&>) :: Functor f => f a -> (a -> b) -> f b as <&> f = f <$> as infixl 1 <&> }}} The proposal was well received, so let's implement it. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14029> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14050: GHC HEAD test suite is broken with Python 3.4.3
by GHC 29 Jul '17

29 Jul '17

#14050: GHC HEAD test suite is broken with Python 3.4.3 -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.4.1 Component: Test Suite | 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: -------------------------------------+------------------------------------- After commit 5e940bd3d554729ce650008a72b4f82a78578a7b, I'm unable to run the GHC test suite on my machine: {{{ ghc2/testsuite$ make test make -C ./tests test make[1]: Entering directory `/home/rgscott/Software/ghc2/testsuite/tests' PYTHON="python3" "python3" ../driver/runtests.py -e "ghc_compiler_always_flags='-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'" -e config.compiler_debugged=True -e ghc_with_native_codegen=1 -e config.have_vanilla=True -e config.have_dynamic=True -e config.have_profiling=False -e ghc_with_threaded_rts=1 -e ghc_with_dynamic_rts=1 -e config.have_interp=True -e config.unregisterised=False -e config.ghc_dynamic_by_default=False -e config.ghc_dynamic=True -e ghc_with_smp=1 -e ghc_with_llvm=1 -e windows=False -e darwin=False -e config.in_tree_compiler=True -e config.cleanup=True -e config.local=True --rootdir=. --config- file=../config/ghc -e 'config.confdir="../config"' -e 'config.platform="x86_64-unknown-linux"' -e 'config.os="linux"' -e 'config.arch="x86_64"' -e 'config.wordsize="64"' -e 'config.timeout=int() or config.timeout' -e 'config.exeext=""' -e 'config.top="/home/rgscott/Software/ghc2/testsuite"' --config 'compiler="/home/rgscott/Software/ghc2/inplace/test spaces/ghc-stage2"' --config 'ghc_pkg="/home/rgscott/Software/ghc2/inplace/test spaces/ghc- pkg"' --config 'haddock=' --config 'hp2ps="/home/rgscott/Software/ghc2/inplace/test spaces/hp2ps"' --config 'hpc="/home/rgscott/Software/ghc2/inplace/test spaces/hpc"' --config 'gs="gs"' --config 'timeout_prog="../timeout/install-inplace/bin/timeout"' -e "config.stage=2" --rootdir=../../libraries/array/tests --rootdir=../../libraries/base/tests --rootdir=../../libraries/binary/tests --rootdir=../../libraries/bytestring/tests --rootdir=../../libraries/containers/tests --rootdir=../../libraries/deepseq/tests --rootdir=../../libraries/directory/tests --rootdir=../../libraries/filepath/tests --rootdir=../../libraries/ghc- compact/tests --rootdir=../../libraries/ghc-prim/tests --rootdir=../../libraries/haskeline/tests --rootdir=../../libraries/hpc/tests --rootdir=../../libraries/pretty/tests --rootdir=../../libraries/process/tests --rootdir=../../libraries /template-haskell/tests --rootdir=../../libraries/unix/tests \ \ \ \ \ \ \ Traceback (most recent call last): File "../driver/runtests.py", line 46, in <module> allow_abbrev=False) TypeError: __init__() got an unexpected keyword argument 'allow_abbrev' make[1]: *** [test] Error 1 make[1]: Leaving directory `/home/rgscott/Software/ghc2/testsuite/tests' make: *** [test] Error 2 }}} geekosaur mentioned that my version of Python is likely to be important: {{{ $ python3 --version Python 3.4.3 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14050> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13173: Investigate old comment at the top of SrcLoc
by GHC 29 Jul '17

29 Jul '17

#13173: Investigate old comment at the top of SrcLoc -------------------------------------+------------------------------------- Reporter: mpickering | Owner: Type: task | Status: new Priority: lowest | Milestone: Component: Compiler | Version: 8.0.1 Keywords: newcomer | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- There is a comment at the top of `SrcLoc` which says {{{ {-# OPTIONS_GHC -fno-omit-interface-pragmas #-} -- Workaround for Trac #5252 crashes the bootstrap compiler without -O -- When the earliest compiler we want to boostrap with is -- GHC 7.2, we can make RealSrcLoc properly abstract }}} This is a well-defined small task so I will mark it for newcomers. 1. Try to work out what the pragma is meant to do by reading #5252 2. Work out whether we can now make `RealSrcLoc` "properly abstract" (if it is not already) 3. Remove or update this comment and pragma. 4. Pray it doesn't break the whole compiler. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13173> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13710: panic with boot and -jX
by GHC 29 Jul '17

29 Jul '17

#13710: panic with boot and -jX -------------------------------------+------------------------------------- Reporter: pacak | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{ % cat A.hs module A where }}} {{{ % cat A.hs-boot module A ( A ) where type A = Maybe () yay :: A -> IO () }}} {{{ % cat B.hs module B where import {-# SOURCE #-} A }}} This panics: {{{ % rm -rf o ; ghc -j2 -outputdir o B [1 of 3] Compiling A[boot] ( A.hs-boot, o/A.o-boot ) [2 of 3] Compiling A ( A.hs, o/A.o ) <no location info>: error: ghc: panic! (the 'impossible' happened) (GHC version 8.2.0.20170503 for x86_64-unknown-linux): tcIfaceGlobal (local): not found You are in a maze of twisty little passages, all alike. While forcing the thunk for TyThing A which was lazily initialized by initIfaceCheck typecheckLoop, I tried to tie the knot, but I couldn't find A in the current type environment. If you are developing GHC, please read Note [Tying the knot] and Note [Type-checking inside the knot]. Consider rebuilding GHC with profiling for a better stack trace. Contents of current type environment: [r15J :-> Identifier ‘$trModule’] Call stack: CallStack (from HasCallStack): prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1134:58 in ghc:Outputable callStackDoc, called at compiler/utils/Outputable.hs:1138:37 in ghc:Outputable pprPanic, called at compiler/iface/TcIface.hs:1689:23 in ghc:TcIface Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} This works: {{{ % rm -rf o ; ghc -j1 -outputdir o B [1 of 3] Compiling A[boot] ( A.hs-boot, o/A.o-boot ) [2 of 3] Compiling A ( A.hs, o/A.o ) A.hs-boot:3:1: error: ‘A.A’ is exported by the hs-boot file, but not exported by the module | 3 | type A = Maybe () | ^^^^^^^^^^^^^^^^^ }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13710> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5252: UNPACK without optimisation leads to panic
by GHC 29 Jul '17

29 Jul '17

#5252: UNPACK without optimisation leads to panic -------------------------+------------------------------------------------- Reporter: | Owner: (none) simonpj | Type: bug | Status: closed Priority: | Milestone: 7.6.2 normal | Component: | Version: 7.6.1 Compiler | Resolution: | Keywords: fixed | Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Type of failure: | Test Case: deSugar/should_compile/T5252, None/Unknown | T5252Take2 Blocked By: | Blocking: Related Tickets: | -------------------------+------------------------------------------------- Comment (by Ben Gamari <ben@…>): In [changeset:"121fee99496d5f5d53a8cd6b08c13a0b6bb9069d/ghc" 121fee99/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="121fee99496d5f5d53a8cd6b08c13a0b6bb9069d" Remove unnecessary GHC option from SrcLoc This was an old workaround for #5252. Fixes #13173. Reviewers: austin, bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3763 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5252#comment:9> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14028: ghc panic: -fexternal-interpreter + .o + QuasiQuotes?
by GHC 29 Jul '17

29 Jul '17

#14028: ghc panic: -fexternal-interpreter + .o + QuasiQuotes? -------------------------------------+------------------------------------- Reporter: blynn | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Keywords: ghc panic | Operating System: Linux impossible | Architecture: x86_64 | Type of failure: Compile-time (amd64) | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- 1. Compile an object file with -fPIC, e.g: {{{ cat > hello.c << EOF #include <stdio.h> void hi(){puts("Hello, World!");} EOF gcc -c -fPIC hello.c }}} 2. Write Haskell that uses QuasiQuotes, e.g: {{{ cat > h.hs << EOF {-# LANGUAGE QuasiQuotes #-} import Text.Heredoc (here) s :: String s = [here|goes nothing|] EOF }}} 3. Compile with -fexternal-interpreter: {{{ cabal install heredoc ghc -fexternal-interpreter h.hs hello.o }}} I saw: [1 of 1] Compiling Main ( h.hs, h.o ) ghc: panic! (the 'impossible' happened) (GHC version 8.0.2 for x86_64-unknown-linux): Loading temp shared object failed: /home/blynn/.local/lib/ghc-8.0.2/ghc-prim-0.5.0.0/libHSghc- prim-0.5.0.0-ghc8.0.2.so: undefined symbol: stg_thawArrayzh Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14028> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12989: ($) can have a more general type
by GHC 29 Jul '17

29 Jul '17

#12989: ($) can have a more general type -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 (Type checker) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The documentation (in section 9.12.1 for GHC 8; I don't know what section it is in 8.2) suggests a hypothetical type for `($)`: {{{#!hs bad :: forall (r1 :: RuntimeRep) (r2 :: RuntimeRep) (a :: TYPE r1) (b :: TYPE r2). (a -> b) -> a -> b bad f x = f x }}} It explains, correctly, that this definition will not work because `x` has a representation-polymorphic type. However, this doesn't actually explain why `($)` doesn't have that type! Indeed, both GHC 8 and 8.2 accept the following: {{{#!hs good :: forall (r1 :: RuntimeRep) (r2 :: RuntimeRep) (a :: TYPE r1) (b :: TYPE r2). (a -> b) -> a -> b good f = f }}} This has very slightly different semantics, but anyone relying on the difference is already doing something they shouldn't. It may or may not be possible to retain the current semantics with some care and magic, if we so desire. I didn't really know how to characterize this ticket properly. It could be considered a documentation bug or a compiler feature request. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12989> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13541: Make it easier to use the gold linker
by GHC 28 Jul '17

28 Jul '17

#13541: Make it easier to use the gold linker -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: feature | Status: new request | 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: -------------------------------------+------------------------------------- As pointed out in #4862, the `gold` linker is significantly faster than BFD `ld`. Currently we use whatever linker `gcc` uses by default. This is an unfortunate situation for users as few packagers take the effort to configure their builds to use `gold`. I think we should consider the following, > Introduce a configure flag (to both the source distribution, and the distributed binary distributions), `--enable-gold`. When enabled, `configure` will check for the functioning of `gcc -fuse-ld=gold`. If found to work `-fuse-ld=gold` would be added to GHC's `optl`. The flag would throw an error on non-ELF platforms (which are not supported by `gold`). While there is admittedly not a whole lot of precedent for this, the status quo means we are leaving a significant bit of compiler performance on the table in a majority of cases. Given that `stack` uses GHC's official bindists, we should try to improve this situation. * -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13541> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13837: Calling qReifyInstances on out-of-scope Name leads to GHC internal error
by GHC 28 Jul '17

28 Jul '17

#13837: Calling qReifyInstances on out-of-scope Name leads to GHC internal error -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Template | Version: 8.0.1 Haskell | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs {-# LANGUAGE TemplateHaskell #-} module Bug where import Language.Haskell.TH.Lib import Language.Haskell.TH.Syntax test_local_tyfam_expansion :: String test_local_tyfam_expansion = $(do fam_name <- newName "Fam" stringE . show =<< qReifyInstances fam_name []) }}} {{{ $ /opt/ghc/8.2.1/bin/ghci Bug2.hs GHCi, version 8.2.0.20170523: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Bug ( Bug2.hs, interpreted ) Bug2.hs:9:5: error: • The exact Name ‘Fam_a4pX’ is not in scope Probable cause: you used a unique Template Haskell name (NameU), perhaps via newName, but did not bind it If that's it, then -ddump-splices might be useful • In the argument of reifyInstances: Fam_0 In the untyped splice: $(do fam_name <- newName "Fam" stringE . show =<< qReifyInstances fam_name []) | 9 | $(do fam_name <- newName "Fam" | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^... Bug2.hs:9:5: error: • GHC internal error: ‘Fam_a4pX’ is not in scope during type checking, but it passed the renamer tcl_env of environment: [] • In the type ‘Fam_a4pX’ In the argument of reifyInstances: Fam_0 In the untyped splice: $(do fam_name <- newName "Fam" stringE . show =<< qReifyInstances fam_name []) | 9 | $(do fam_name <- newName "Fam" | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^... }}} This appears to have started happening in GHC 7.10, since with 7.8, you only get this: {{{ GHCi, version 7.8.4: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. [1 of 1] Compiling Bug ( Bug2.hs, interpreted ) Loading package array-0.5.0.0 ... linking ... done. Loading package deepseq-1.3.0.2 ... linking ... done. Loading package containers-0.5.5.1 ... linking ... done. Loading package pretty-1.1.1.1 ... linking ... done. Loading package template-haskell ... linking ... done. Bug2.hs:9:5: The exact Name ‘Fam_a2gK’ is not in scope Probable cause: you used a unique Template Haskell name (NameU), perhaps via newName, but did not bind it If that's it, then -ddump-splices might be useful In the argument of reifyInstances: Fam_0 In the splice: $(do { fam_name <- newName "Fam"; stringE . show =<< qReifyInstances fam_name [] }) }}} This problem appears to be somewhat specific to `qReifyInstances`, since switching it out with `qReify` does not trigger the internal error: {{{#!hs {-# LANGUAGE TemplateHaskell #-} module Bug where import Language.Haskell.TH.Lib import Language.Haskell.TH.Syntax test_local_tyfam_expansion :: String test_local_tyfam_expansion = $(do fam_name <- newName "Fam" stringE . show =<< qReify fam_name) }}} {{{ GHCi, version 8.2.0.20170523: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Bug ( Bug2.hs, interpreted ) Bug2.hs:9:5: error: • The exact Name ‘Fam_a4od’ is not in scope Probable cause: you used a unique Template Haskell name (NameU), perhaps via newName, but did not bind it If that's it, then -ddump-splices might be useful • In the untyped splice: $(do fam_name <- newName "Fam" stringE . show =<< qReify fam_name) | 9 | $(do fam_name <- newName "Fam" | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^... Bug2.hs:9:5: error: • The exact Name ‘Fam_a4od’ is not in scope Probable cause: you used a unique Template Haskell name (NameU), perhaps via newName, but did not bind it If that's it, then -ddump-splices might be useful • In the untyped splice: $(do fam_name <- newName "Fam" stringE . show =<< qReify fam_name) | 9 | $(do fam_name <- newName "Fam" | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^... Bug2.hs:9:5: error: • ‘Fam_a4od’ is not in the type environment at a reify • In the untyped splice: $(do fam_name <- newName "Fam" stringE . show =<< qReify fam_name) | 9 | $(do fam_name <- newName "Fam" | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^... }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13837> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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