November 2015 - ghc-tickets

[GHC] #10785: ghc-pkg appends colon to db path when piped/redirected
by GHC 12 Dec '15

12 Dec '15

#10785: ghc-pkg appends colon to db path when piped/redirected -------------------------------------+------------------------------------- Reporter: jgertm | Owner: jgertm Type: bug | Status: new Priority: normal | Milestone: Component: ghc-pkg | Version: 7.10.2 Keywords: colon pipe | Operating System: Unknown/Multiple redirect ghc-pkg list | Architecture: | Type of failure: Other Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- Quite simple. Compare the first line of output from {{{#!sh ghc-pkg list ghc-pkg list | head }}} In the second command's output, a colon gets appended at the end of the first line, compared to the first command. This is generally undesired behaviour, since the intent of redirection is to further process the output of the original command. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10785> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11142: Type-level skolem capture leads to core lint error
by GHC 12 Dec '15

12 Dec '15

#11142: Type-level skolem capture leads to core lint error -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 (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 following ill-typed code is accepted. {{{ {-# LANGUAGE PolyKinds, RankNTypes #-} module Bug where data SameKind :: k -> k -> * foo :: forall b. (forall (a :: k). SameKind a b) -> () foo = undefined }}} Indeed, Core Lint catches this. But the type-checker should. The problem is that `SameKind` forces `a` and `b` to have the same kind. But they can't, because `a`'s kind is out of scope at `b`'s binding site. The program should be rejected. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11142> 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] #10937: "ghc -no-link --make A.hs -o foo" does something silly
by GHC 11 Dec '15

11 Dec '15

#10937: "ghc -no-link --make A.hs -o foo" does something silly -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: new Priority: lowest | Milestone: Component: Compiler | Version: 7.10.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | -------------------------------------+------------------------------------- If I run "ghc -no-link --make A.hs -o foo" it puts the first object file it compiles into the `-o` location, and then fails because the object is not where is expected. {{{ [ezyang@hs01 ghc-fat-interface]$ ghc -no-link --make B.hs -o foo [1 of 2] Compiling A ( A.hs, A.o ) ./A.o: getFileStatus: does not exist (No such file or directory) }}} Without `-no-link` I get a more reasonable warning, and object files are not redirected. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10937> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11146: Manual eta expansion leads to orders of magnitude less allocations
by GHC 10 Dec '15

10 Dec '15

#11146: Manual eta expansion leads to orders of magnitude less allocations -------------------------------------+------------------------------------- Reporter: niteria | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 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: -------------------------------------+------------------------------------- While working on deterministic free variable computation I run into some performance issues. I narrowed it down to code that when eta expanded performed less allocations. I ended up writing a benchmark and for large examples the eta expanded versions performs orders of magnitude less allocations. The results of my test: {{{ EtaExpanded test3 50,450,112 bytes allocated in the heap real 0.89 EtaReduced test3 3,661,740,240 bytes allocated in the heap real 3.66 }}} The whole source is here: https://github.com/niteria/deterministic-fvs, I'm also attaching the two interesting implementations. I experimented with it a little and GHC eta-expanded when I didn't have mutually recursive bindings. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11146> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10527: Panic Simplifier ticks exhausted with type families
by GHC 08 Dec '15

08 Dec '15

#10527: Panic Simplifier ticks exhausted with type families -------------------------------------+------------------------------------- Reporter: sopvop | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1-rc1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- I've tried to compile my vinyl-like records with 7.10.2-rc1 and got: {{{ ghc: panic! (the 'impossible' happened) (GHC version 7.10.1.20150612 for x86_64-unknown-linux): Simplifier ticks exhausted When trying RuleFired Class op rreplace To increase the limit, use -fsimpl-tick-factor=N (default 100) If you need to do this, let GHC HQ know, and what factor you needed To see detailed counts use -ddump-simpl-stats Total ticks: 225484 Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} Attached self contained test compiles with 7.10.1, but fails with 7.10.2-rc1 when compiled with optimizations. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10527> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10653: PatternSynonyms should be imported/exported as part of the wildcard notation
by GHC 08 Dec '15

08 Dec '15

#10653: PatternSynonyms should be imported/exported as part of the wildcard notation -------------------------------------+------------------------------------- Reporter: gridaphobe | Owner: Type: feature | Status: new request | Milestone: 7.12.1 Priority: normal | Version: 7.11 Component: Compiler | Operating System: Unknown/Multiple Keywords: pattern | Type of failure: None/Unknown synonyms | Blocked By: Architecture: | Related Tickets: Unknown/Multiple | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Suppose I have the following two modules. {{{#!hs {-# LANGUAGE PatternSynonyms #-} module A where data A = A2 Int Int pattern A1 a <- A2 a _ where A1 a = A2 a 0 }}} {{{#!hs module B where import A ( A(..) ) a = A1 0 }}} When I try to compile `B.hs` I get an error because `A1` is unbound in module `B`. {{{ $ ghc --make B.hs [1 of 2] Compiling A ( A.hs, A.o ) [2 of 2] Compiling B ( B.hs, B.o ) B.hs:5:5: Not in scope: data constructor ‘A1’ Perhaps you meant ‘A2’ (imported from A) }}} The issue is that the import `A(..)` brings all of `A`s data constructors and accessors into scope, but not any associated pattern synonyms. Instead I have to enable `PatternSynonyms` in module `B` (or just import everything from `A`). {{{#!hs {-# LANGUAGE PatternSynonyms #-} module B where import A ( A(..), pattern A1 ) a = A1 0 }}} I'd like to propose that we extend the semantics of the `A(..)` import/export notation to include any associated pattern synonyms. I think this is in line with the spirit of `PatternSynonyms`, that the extension should allow internal refactoring without causing API breakage, and that the extension should only need to be enabled to *define* pattern synonyms. FYI, this issue does appear in the wild, I ran into it while working on https://phabricator.haskell.org/D861 and had to modify two import lists in Cabal. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10653> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10444: Tex.Read.Lex.lex broken
by GHC 07 Dec '15

07 Dec '15

#10444: Tex.Read.Lex.lex broken -------------------------------------+------------------------------------- Reporter: strake888 | Owner: ekmett Type: bug | Status: new Priority: normal | Milestone: Component: Core | Version: 7.10.1 Libraries | Operating System: Unknown/Multiple Keywords: | Type of failure: Incorrect result Architecture: | at runtime Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- {{{ Prelude> lex "&) = mempty" [("&",") = mempty")] Prelude> lex "∘) = mempty" [] }}} I traced this problem to Text.Read.Lex.lex -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10444> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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