May 2018 - ghc-tickets

[GHC] #15055: ghci - improve error on hidden package
by GHC 13 May '18

13 May '18

#15055: ghci - improve error on hidden package -------------------------------------+------------------------------------- Reporter: akfp | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: GHCi | Version: 8.2.2 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: -------------------------------------+------------------------------------- A user boldly types: {{{ > import Data.Foo <no location info>: error: Could not find module ‘Data.Foo’ It is a member of the hidden package ‘package-foo-0.1.0.0@package- foo-0.1.0.0-5Itxx5SAgKEAspB2MHVKqi’. }}} The above error message is rather useless for a newcomer to ghci. After lots of googling, the user figures that `:set -v -package package-foo` seems to solve it. The original error should be: {{{ > import Data.Foo <no location info>: error: Could not find module ‘Data.Foo’ It is a member of the hidden package ‘package-foo-0.1.0.0@package- foo-0.1.0.0-5Itxx5SAgKEAspB2MHVKqi’. Try :set -package package-foo to make it visible. }}} Or something like that. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15055> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 8

[GHC] #11389: Print a message when loading a .ghci file
by GHC 13 May '18

13 May '18

#11389: Print a message when loading a .ghci file -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: GHCi | Version: 7.8.4 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: -------------------------------------+------------------------------------- It'd be nice to have a notice displayed when ghci loads a .ghci file, something like {{{ rwbarton@morphism:~$ ghci-7.10.1 GHCi, version 7.10.1: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rwbarton/.ghci Prelude> }}} I want this mostly so that we can tell whether people filing ghci bugs might have anything relevant in their `.ghci` files. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11389> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 4

[GHC] #15139: EmptyCase produces incorrect SrcSpans
by GHC 12 May '18

12 May '18

#15139: EmptyCase produces incorrect SrcSpans -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.2 (Parser) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Poor/confusing Unknown/Multiple | error message Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- If you compile the following program, you'll get a warning for `f` with an improperly placed `SrcSpan`: {{{#!hs {-# LANGUAGE EmptyCase #-} {-# LANGUAGE TypeOperators #-} {-# OPTIONS_GHC -Wincomplete-patterns #-} module Bug where import Data.Type.Equality can'tHappen :: Int :~: Bool can'tHappen = undefined f, g :: Bool -> Bool f True = case can'tHappen of {} g True = case () of () -> True }}} {{{ $ /opt/ghc/8.4.2/bin/ghci Bug.hs GHCi, version 8.4.2: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Bug ( Bug.hs, interpreted ) Bug.hs:12:1: warning: [-Wincomplete-patterns] Pattern match(es) are non-exhaustive In an equation for ‘f’: Patterns not matched: False | 12 | f True = case can'tHappen of {} | ^^^^^^^^^^^^^ Bug.hs:13:1: warning: [-Wincomplete-patterns] Pattern match(es) are non-exhaustive In an equation for ‘g’: Patterns not matched: False | 13 | g True = case () of () -> True | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Ok, one module loaded. }}} Compare that to the warning for `g`, whose `SrcSpan` spans the entire clause, as expected. The bug lies in the parser—patch incoming. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15139> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 3

Re: [GHC] #4017: Unhelpful error message in GHCi
by GHC 12 May '18

12 May '18

#4017: Unhelpful error message in GHCi -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: bug | Status: new Priority: lowest | Milestone: Component: Compiler | Version: 6.12.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by supersven): * owner: supersven => (none) Comment: I investigated a few days, then got stuck and lost interest... I unassign this ticket so someone else may pick it up. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4017#comment:16> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

[GHC] #12721: Implement sigINT handler for Window's timeout.exe
by GHC 12 May '18

12 May '18

#12721: Implement sigINT handler for Window's timeout.exe ----------------------------------------+---------------------------- Reporter: Phyx- | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Test Suite | Version: 8.0.1 Keywords: | Operating System: Windows Architecture: Unknown/Multiple | Type of failure: Other Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ----------------------------------------+---------------------------- On linux we current register a sigINT handler and kill the child processed. On Windows we don't. This sometimes leaves dangling processes when the testsuite is interrupted. Causing future failures until the dangling processes are killed. We already specifically create a job group and assign the processors to those jobs. All we have to do is register the handler and kill the process if the handler is called. See https://msdn.microsoft.com/en- us/library/windows/desktop/ms686016(v=vs.85).aspx -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12721> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 6

[GHC] #15101: $tooldir not expanded for NoFib
by GHC 12 May '18

12 May '18

#15101: $tooldir not expanded for NoFib -------------------------------------+------------------------------------- Reporter: AndreasK | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: NoFib | Version: benchmark suite | Keywords: | Operating System: Windows Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The nofib suite looks for gcc under $tooldir which doesn't seem to be expanded/set. {{{ > ~/ghc_head/nofib/shootout/fasta $ make boot $tooldir/mingw/bin/gcc.exe -std=gnu99 -O3 -fomit-frame-pointer fasta-c.c -o fasta-c /bin/sh: /mingw/bin/gcc.exe: No such file or directory make: *** [Makefile:22: fasta-c] Error 127 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15101> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 6

[GHC] #15140: GHC 8.4.2 installation crash with Stack
by GHC 11 May '18

11 May '18

#15140: GHC 8.4.2 installation crash with Stack -------------------------------------+------------------------------------- Reporter: fpanahi | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Build System | Version: 8.4.2 Keywords: | Operating System: Windows Architecture: x86 | Type of failure: Installing GHC | failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I got this problem while installing GHC 8.4.2 with the "stack install" command. I had successfully installed Stack and cloned https://github.com/haskell/haskell-ide-engine beforehand. The OS is Windows 10 (64b). The error message is on the screen copy herein attached. It is already such a long and difficult process to install Haskell, compared to similar PL ... -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15140> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 6

[GHC] #15132: Hadrian-built GHC cannot locate `unlit`
by GHC 11 May '18

11 May '18

#15132: Hadrian-built GHC cannot locate `unlit` ----------------------------------------+--------------------------------- Reporter: tdammers | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Build System | Version: Keywords: | Operating System: Linux Architecture: Unknown/Multiple | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ----------------------------------------+--------------------------------- When trying to compile a Literate Haskell source with a Hadrian-built GHC, compilation fails due to GHC not finding the `unlit` binary. How to reproduce: - Compile GHC using the default Hadrian `build.sh` script - Create a minimal LHS file, e.g. `echo '> main = return ()' > test.lhs` - Compile the LHS file with the in-place GHC: `$GHC_SRC_TREE/_build/stage1/bin/ghc test.lhs` This fails with something like: {{{ ghc: could not execute: $GHC_SRC_TREE/_build/stage1/lib/bin/unlit }}} However, the `unlit` binary is in `$GHC_SRC_TREE/_build/stage1/bin/unlit`. Considering how `make`-built GHC works fine, this seems to be a misconfiguration in the Hadrian build system. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15132> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 3

Re: [GHC] #4806: Make error message more user friendly when module is not found because package is unusable
by GHC 09 May '18

09 May '18

#4806: Make error message more user friendly when module is not found because package is unusable -------------------------------------+------------------------------------- Reporter: mitar | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.0.1 Resolution: | Keywords: newcomer Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by sgillespie): I can seem to reproduce the issue by running {{{ cabal sandbox init cabal install MonadRandom cabal exec -- ghc-pkg unregister --force fail cabal repl }}} Then import anything from the now-unusable package {{{ Prelude> :m + Control.Monad.Random <no location info>: error: Could not find module ‘Control.Monad.Random’ Perhaps you meant Control.Monad.Reader (from mtl-2.2.2) Control.Monad.Cont (from mtl-2.2.2) Control.Monad.Error (from mtl-2.2.2) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4806#comment:23> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

[GHC] #15125: Typeclass instance selection depends on the optimisation level
by GHC 09 May '18

09 May '18

#15125: Typeclass instance selection depends on the optimisation level -------------------------------------+------------------------------------- Reporter: nicuveo | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.2.2 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: -------------------------------------+------------------------------------- (See the attached files for a minimal case.) A file A defines a typeclass, and gives an incoherent instance for all types a, and exports a function relying on said typeclass. A file B defines some data types, makes them specific instances of that class. Which instance ends up being picked depends on the optimisation level they're compiled with. //A.hs// {{{#!hs class A a where someValue :: a -> Maybe Int instance {-# INCOHERENT #-} A a where someValue = const Nothing getInt :: A a => a -> Int getInt x = fromMaybe 0 $ someValue x }}} //B.hs// {{{#!hs data B = B Int instance A B where someValue (B x) = Just x getBInt :: Int getBInt = getInt $ B 42 }}} //Main.hs// {{{#!hs main = print getBInt }}} **Upon compiling with -O0, this prints 42; upon compiling with -O2, this print 0.** (Interestingly, if the redundant class constraint is removed from getInt, then it always prints 0.) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15125> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 12