November 2016 - ghc-tickets

[GHC] #11501: Building nofib/fibon returns permission denied
by GHC 08 Jun '17

08 Jun '17

#11501: Building nofib/fibon returns permission denied -------------------------------------+------------------------------------- Reporter: rem | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: NoFib | Version: 7.10.3 benchmark suite | Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: None/Unknown (amd64) | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Building nofib/fibon returns permission denied: {{{ == make boot - --no-print-directory; in /h/ywang30/nofib/fibon/Hackage/Bzlib ------------------------------------------------------------------------ // Codec/Compression/BZip/Stream.hsc make[3]: execvp: //: Permission denied make[3]: *** [Codec/Compression/BZip/Stream.hs] Error 127 }}} Steps to reproduce: Edit nofib/mk/boilerplate.mk:35 to NoFibSubDirs = fibon make clean && make boot in nofib/ -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11501> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11317: Test prog003 fails with segfault on Windows (GHCi)
by GHC 07 Jun '17

07 Jun '17

#11317: Test prog003 fails with segfault on Windows (GHCi) --------------------------------------+------------------------------- Reporter: rdragon | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 7.11 Keywords: | Operating System: Windows Architecture: x86_64 (amd64) | Type of failure: GHCi crash Test Case: | Blocked By: Blocking: | Related Tickets: #11234 Differential Rev(s): | Wiki Page: --------------------------------------+------------------------------- On my `x86_64` Windows machine test `prog003` fails with a segfault: {{{ cd ./ghci/prog003 && ghciWayFlags=-static HC="/home/Rik/ghc/inplace/bin /ghc-stage2.exe" HC_OPTS="-dcore-lint -dcmm-lint -dno-debug-output -no- user-package-db -rtsopts -fno-warn-tabs -fno-warn-missed-specialisations -fno-ghci-history " "/home/Rik/ghc/inplace/bin/ghc-stage2.exe" -dcore-lint -dcmm-lint -dno-debug-output -no-user-package-db -rtsopts -fno-warn-tabs -fno-warn-missed-specialisations -fno-ghci-history --interactive -v0 -ignore-dot-ghci +RTS -I0.1 -RTS <prog003.script > prog003.run.stdout 2> prog003.run.stderr >> prog003.run.stdout 2>> prog003.run.stderr Wrong exit code (expected 0 , actual 1 ) Stdout: Run 1 a :: Int -> Int 168 Run 2 (A.a,B.b,C.c,D.d) :: (Float -> Float, Float -> Float, Float -> Float, Float -> Float) 28.0 Run 3 (A.a,B.b,C.c,D.d) :: (Float -> Float, Float -> Float, Float -> Float, Float -> Float) 28.0 Run 4 (A.a,B.b,C.c,D.d) :: (Float -> Float, Float -> Float, Float -> Float, Float -> Float) 28.0 Run 5 (A.a,B.b,C.c,D.d) :: (Float -> Float, Float -> Float, Float -> Float, Float -> Float) 28.0 Run 6 (A.a,B.b,C.c,D.d) :: (Float -> Float, Float -> Float, Float -> Float, Float -> Float) 28.0 Run 7 (A.a,B.b,C.c,D.d) :: (Float -> Float, Float -> Float, Float -> Float, Float -> Float) 28.0 Run 8 Segmentation fault/access violation in generated code Stderr: *** unexpected failure for prog003(ghci) }}} (I do not think it is an access violation error since when I remove [https://github.com/ghc/ghc/blob/c2fab84239299176a8e72aa26ae894019d677bd9/te… line 65] and everything below line 70, the same stdout is generated.) This looks related to ticket #11234. The GHC version used was [http://git.haskell.org/ghc.git/commit/df6cb57b32d94b7f6f7c9a86207adfeee9712… df6cb57b32d94b7f6f7c9a86207adfeee9712ed6], although I already noticed the problem with a version a few days older. If someone could point me to information about how to install GDB suitable for debugging GHC on my Windows machine I will try to post the stack trace. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11317> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8703: Use guard pages rather than heap checks
by GHC 07 Jun '17

07 Jun '17

#8703: Use guard pages rather than heap checks ------------------------------------+------------------------------------- Reporter: schyler | Owner: simonmar Type: feature request | Status: new Priority: normal | Milestone: Component: Runtime System | Version: Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- By mmap'ing memory using MAP_ANONYMOUS (or /dev/zero) as PROT_NONE (Windows has an equivalent functionality with VirtualAlloc), it's possible to create a page that will fault when read or written to. It may be possible to remove the heap checks in the runtime, speeding up allocations, and instead expand the heap when a fault is raised. This is likely cheaper for large pages full of many small allocations than the cost of the heap checking branch. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8703> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12778: Expose variables bound in quotations to reify
by GHC 06 Jun '17

06 Jun '17

#12778: Expose variables bound in quotations to reify -------------------------------------+------------------------------------- Reporter: | Owner: facundo.dominguez | Type: bug | Status: new 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: -------------------------------------+------------------------------------- Consider the following program: {{{ {-# LANGUAGE TemplateHaskell #-} module A where import Language.Haskell.TH as TH import Language.Haskell.TH.Syntax as TH foo :: IO () foo = $([| let x = True in $(do addModFinalizer $ do Just name <- TH.lookupValueName "x" TH.reify name >>= runIO . print [| return () |] ) |]) }}} When compiled, {{{TH.lookupValueName}}} fails to find {{{x}}}. {{{ $ inplace/bin/ghc-stage2 A.hs -fforce-recomp [1 of 1] Compiling A ( A.hs, A.o ) A.hs:7:9: error: • Pattern match failure in do expression at A.hs:9:23-31 • In the expression: (let x_a3Jy = True in return ()) In an equation for ‘foo’: foo = (let x_a3Jy = True in return ()) }}} It would make producing bindings in {{{inline-java}}} better if the type of {{{x}}} could be found in the finalizer. According to comments in ghc, {{{[| \x -> $(f [| x |]) |]}}} desugars to {{{ gensym (unpackString "x"#) `bindQ` \ x1::String -> lam (pvar x1) (f (var x1)) }}} which erases any hint that a splice point existed at all. This information is necessary to know which variables were in scope. How about we add a some new methods to the `Q` monad for the sake of marking inner splices: {{{ class Q m where ... qSpliceE :: m Exp -> m Exp qSpliceP :: m Pat -> m Pat qSpliceT :: m Type -> m Type ... }}} Now {{{[| \x -> $(f [| x |]) |]}}} would desugar to {{{ gensym (unpackString "x"#) `bindQ` \ x1::String -> lam (pvar x1) (qSpliceE (f (var x1))) }}} When the renamer executes these primitives, it would be aware of the inner splices and could treat them similarly to top-level splices. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12778> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12710: Make some reserved Unicode symbols "specials"
by GHC 06 Jun '17

06 Jun '17

#12710: Make some reserved Unicode symbols "specials" -------------------------------------+------------------------------------- Reporter: JoshPrice247 | Owner: JoshPrice247 Type: feature | Status: new request | Priority: low | Milestone: Component: Compiler | Version: 8.0.1 (Parser) | Keywords: Unicode, | Operating System: Unknown/Multiple UnicodeSyntax | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The following comment is in `compiler/parser/Lexer.x`: > ToDo: ideally, → and ∷ should be "specials", so that they cannot > form part of a large operator. This would let us have a better > syntax for kinds: ɑ∷*→* would be a legal kind signature. (maybe). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12710> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10600: -fwarn-incomplete-patterns doesn't work with -fno-code
by GHC 05 Jun '17

05 Jun '17

#10600: -fwarn-incomplete-patterns doesn't work with -fno-code -------------------------------------+------------------------------------- Reporter: akio | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Incorrect Unknown/Multiple | warning at compile-time Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- `-fwarn-incomplete-patterns` doensn't seem to generate any warnings when `-fno-code` is specified. To reproduce, save this module as `foo.hs`. {{{#!hs module Foo where foo True = 4 }}} and compile with `-fwarn-incomplete-patterns`, with and without `-fno- code`. {{{ % ghc -fwarn-incomplete-patterns -fforce-recomp foo.hs [1 of 1] Compiling Foo ( foo.hs, foo.o ) foo.hs:2:1: Warning: Pattern match(es) are non-exhaustive In an equation for ‘foo’: Patterns not matched: False % ghc -fwarn-incomplete-patterns -fforce-recomp -fno-code foo.hs [1 of 1] Compiling Foo ( foo.hs, nothing ) % }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10600> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11032: Missing result type handling for State# s in foreign import prim.
by GHC 03 Jun '17

03 Jun '17

#11032: Missing result type handling for State# s in foreign import prim. -------------------------------------+------------------------------------- Reporter: ekmett | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 (FFI) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I've been using `foreign import prim` for a while now to craft custom primops on an as-needed basis. Attempting to write {{{#!hs {-# LANGUAGE MagicHash #-} {-# LANGUAGE UnboxedTuples #-} {-# LANGUAGE UnliftedFFITypes #-} {-# LANGUAGE GHCForeignImportPrim #-} {-# LANGUAGE ForeignFunctionInterface #-} foreign import prim "pinThreadzh" pinThread# :: State# s -> (# State# s, Int#, Int# #) foreign import prim "unpinThreadzh" unpinThread# :: State# s -> State# s }}} threw me for a loop when it didn't work. The former works fine. The latter complains that `State# s` isn't a valid result type! {{{ src/Concurrent/Internal/Thread.hs:23:1: Unacceptable result type in foreign declaration: ‘State# s’ cannot be marshalled in a foreign call When checking declaration: foreign import prim safe "static unpinThreadzh" unpinThread# :: State# s -> State# s }}} Builtin primitives work this way all the time, so I'm guessing we just missed it in a case statement somewhere inside the compiler when dealing with `foreign import prim` support. I can likely hack around it by giving back something like `(# State# s #)` for now but that is a rather unsatisfying solution. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11032> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12499: Support multiple library import libs
by GHC 02 Jun '17

02 Jun '17

#12499: Support multiple library import libs -------------------------------------+------------------------------------- Reporter: Phyx- | Owner: Type: feature | Status: new request | Priority: normal | Milestone: 8.2.1 Component: Runtime | Version: 8.0.1 System (Linker) | Keywords: | Operating System: Windows Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Our implementation of import libraries only support single library import libs. These are by far the most common ones. However it is possible to make multi library import libraries. E.g. one import library pointing to multiple dlls. `binutils` correct supports these and with #5987 GHC will be relying on them to work. It makes sense that we are able to load them in GHCi as well. This will be required for a fully working dynamic GHC on Windows. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12499> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12237: Constraint resolution vs. type family resolution vs. TypeErrors
by GHC 01 Jun '17

01 Jun '17

#12237: Constraint resolution vs. type family resolution vs. TypeErrors -------------------------------------+------------------------------------- Reporter: cactus | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple CustomTypeErrors | Architecture: | Type of failure: Other Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Via http://stackoverflow.com/q/37769351/477476, given the following setup: {{{#!hs {-# LANGUAGE DataKinds, TypeFamilies, TypeOperators #-} {-# LANGUAGE FlexibleContexts, MultiParamTypeClasses, UndecidableInstances #-} import Data.Proxy import GHC.TypeLits type family TEq a b where TEq a a = a TEq a b = TypeError (Text "TEq error") type family F a where F () = () F (a, b) = TEq (F a) (F b) F a = TypeError (Text "Unsupported type: " :<>: ShowType a) }}} and the following usages of `F` and `TEq`: {{{#!hs class (repr ~ F a) => C repr a foo :: (C (F a) a) => proxy a -> () foo _ = () main :: IO () main = print $ foo (Proxy :: Proxy (Int, ())) }}} This results in {{{ * No instance for (C (TEq (TypeError ...) ()) (Int, ())) arising from a use of `foo' * In the second argument of `($)', namely `foo (Proxy :: Proxy (Int, ()))' In the expression: print $ foo (Proxy :: Proxy (Int, ())) In an equation for `main': main = print $ foo (Proxy :: Proxy (Int, ())) }}} but it would be preferable to bail out earlier when `F Int` is resolved to `TypeError ...` instead of propagating that all the way to the `C` constraint. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12237> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12820: Regression around pattern synonyms and higher-rank types
by GHC 31 May '17

31 May '17

#12820: Regression around pattern synonyms and higher-rank types -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 (Type checker) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- GHC 8.0.1 accepts, but HEAD rejects: {{{#!hs {-# LANGUAGE PatternSynonyms, RankNTypes, ViewPatterns #-} module Bug where pattern P :: (forall a. a -> a) -> String pattern P x <- (\ _ -> id -> x) }}} (Sidenote: kudos to the parser on figuring out my view pattern.) HEAD gives this error: {{{ Bug.hs:6:30: error: • Couldn't match expected type ‘forall a. a -> a’ with actual type ‘a0 -> a0’ • In the declaration for pattern synonym ‘P’ • Relevant bindings include x :: a0 -> a0 (bound at Bug.hs:6:30) }}} The code looks correct to me. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12820> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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