September 2014 - ghc-tickets

[GHC] #8165: Use GeneralizedNewtypeDeriving to automatically create associated type families
by GHC 13 Apr '18

13 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 30 Mar '18

30 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] #8542: Suggest NegativeLiterals
by GHC 14 Mar '18

14 Mar '18

#8542: Suggest NegativeLiterals ------------------------------------+------------------------------------- Reporter: monoidal | 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: | ------------------------------------+------------------------------------- If we write -128 :: Int8, we get a useful warning (#7895), but it would be even better to suggest NegativeLiterals. Patch incoming. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8542> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8772: ghci should safe history more often
by GHC 05 Mar '18

05 Mar '18

#8772: ghci should safe history more often ----------------------------------------------+---------------------------- Reporter: nomeata | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: GHCi | Version: 7.6.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Moderate (less than a day) | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: ----------------------------------------------+---------------------------- It is very annoying if `ghci` crashes (due to using a foreign library wrongly, for example), and then the history is lost. It should be simple to save each line to history before it is being executed. Maybe a good task for new contributors? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8772> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8597: Git Hook script to prevent large binary blobs being checked in
by GHC 24 Feb '18

24 Feb '18

#8597: Git Hook script to prevent large binary blobs being checked in ------------------------------------+------------------------------------- Reporter: hvr | Owner: hvr Type: task | Status: new Priority: normal | Milestone: Component: Trac & Git | Version: Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- It has already occurred in the past in `testsuite.git` repo, that executables were checked in by accident, and caused the Git history to get bloated. In order to avoid such accidents in the future a Git hook script in the style of [http://stackoverflow.com/questions/20226132/is-there-a-git-hook- which-can-prevent-binary-check-ins this] might be useful, but taking also into account the size, and/or possibly with a magic safeword to be put in the commit message, to override the check for a single commit, if the author really knows what (s)he's doing. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8597> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9429: Alternative to type family Any
by GHC 19 Feb '18

19 Feb '18

#9429: Alternative to type family Any -------------------------------------+------------------------------------- Reporter: mboes | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.9 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: 9097, 9380 | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- In GHC HEAD, `Any` is no longer a datatype. There are good reasons for this change, one of which was explained in #9097, the original ticket, and another in #9380. Unfortunately, a casualty of this change is that it is no longer easy to generalize the [https://hackage.haskell.org/package/rank1dynamic|rank1dynamic package] to rank-1 types with type variables of arbitrary kind (not just `*`). We submitted a way to do so [here], that exploits the fact that `Any` has the very magical property of inhabiting *all* kinds, including closed ones. This works for GHC 7.8, but won't work in HEAD, because we require that there exists a `Typeable` instance for `Any`, just as there are `Typeable` instances for any other type one wishes to have instances for. The reason is that now that `Any` is a type family, `Any` is no longer a legal instance head. There are several possible solutions that I see: * while it's clearly dangerous for the compiler to be inserting the old `Any` during typechecking from the moment that we have computation in types over closed kinds, we may still want the old `Any`, say under a different name, as a backdoor. It wouldn't be used by the compiler during type checking - only by packages such as rank1dynamic. I believe that furthermore, if we restrict the old `Any` to not inhabit closed kinds, then none of the problems cited in the above tickets arise. * Instead of making the new `Any` a type family, keep it a datatype, but ban it from inhabiting closed kinds. I don't know if such an `Any` would be sufficient for the purposes of GHC, however. * Hardwire a `Typeable` instance for the `Any` type family (not sure if this makes sense). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9429> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8258: GHC accepts `data Foo where` in H2010 mode
by GHC 15 Feb '18

15 Feb '18

#8258: GHC accepts `data Foo where` in H2010 mode --------------------------+------------------------------------------------ Reporter: hvr | Owner: Type: bug | Status: new Priority: low | Milestone: 7.8.1 Component: | Version: 7.0.4 Compiler | Operating System: Unknown/Multiple Keywords: | Type of failure: GHC accepts invalid program Architecture: | Test Case: Unknown/Multiple | Blocking: Difficulty: | Unknown | Blocked By: | Related Tickets: | --------------------------+------------------------------------------------ According to the Haskell2010 report, The grammar productions relevant for `data` declarations are the following: {{{ topdecl → data [context =>] simpletype [= constrs] [deriving] }}} (from [http://www.haskell.org/onlinereport/haskell2010/haskellch4.html#x10-680004.2 4.2.1 Algebraic Datatype Declarations]) However, GHC 7.0.4/7.4.2/7.6.3/HEAD all happily compile the following Haskell module without any warning when using `-XHaskell2010 -Wall`, even though this is not valid Haskell2010 afaik: {{{#!hs module Foo where data Foo where }}} The trailing `where` in the `data` declaration is not valid Haskell2010 (without language extensions such as `GADT`). At the very least, this divergence from the Haskell Report should be mentioned in [http://www.haskell.org/ghc/docs/latest/html/users_guide /bugs-and-infelicities.html#haskell-standards-divergence 14.1.1. Divergence from Haskell 98 and Haskell 2010]. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8258> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9269: Type families returning quantified types
by GHC 14 Feb '18

14 Feb '18

#9269: Type families returning quantified types ------------------------------------+------------------------------------- Reporter: pumpkin | Owner: Type: feature request | 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: | ------------------------------------+------------------------------------- Is there a fundamental reason for not being able to use quantification in a type family? I'd very much like to be able to do it, obviously turning on RankNTypes if necessary. I'm looking for things like this: {{{#!haskell type family Foo (x :: Bool) where Foo True = forall a. [a] Foo False = () }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9269> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8684: hWaitForInput cannot be interrupted by async exceptions on unix
by GHC 05 Feb '18

05 Feb '18

#8684: hWaitForInput cannot be interrupted by async exceptions on unix ------------------------------------+------------------------------------- Reporter: nh2 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: libraries/base | 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: | ------------------------------------+------------------------------------- http://hackage.haskell.org/package/base-4.6.0.1/docs/System-Timeout.html claims that {{{timeout}}} can interrupt {{{hWaitForInput}}}, but in fact that's false (e.g. mentioned in https://ghc.haskell.org/trac/ghc/ticket/7353#comment:4) {{{ -- import Control.Concurrent import System.IO import System.Timeout main = timeout (1 * 1000000) $ hWaitForInput stdin (5 * 1000) }}} will not be killed after 1 second, but instead wait for the full 5 seconds timeout passed to {{{hWaitForInput}}}. The implementation is {{{ready}}} at http://www.haskell.org/ghc/docs/latest/html/libraries/base/src/GHC-IO- FD.html, where we have two foreign calls: {{{safe fdReady}}} and {{{unsafe unsafe_fdReady}}}. The actual C implementation is at https://github.com/haskell- suite/base/blob/master/cbits/inputReady.c#L16. It uses {{{select}}} on Unix, and does check for {{{EINTR}}}, so I believe that according to http://www.haskell.org/ghc/docs/7.6.3/html/users_guide/ffi.html#ffi- interruptible both foreign calls can be replaced by a single {{{interruptible}}} one. Is that true? If not, it's a documentation bug in {{{timeout}}} at least. Also, does {{{interruptible}}}, apart from allowing the function to be interrupted, behave more like {{{safe}}} or {{{unsafe}}}? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8684> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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