October 2014 - ghc-tickets

[GHC] #9510: Prelude.!! is not a good consumer
by GHC 28 Oct '14

28 Oct '14

#9510: Prelude.!! is not a good consumer -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: libraries/base | Version: 7.8.3 Keywords: fusion | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Runtime Blocked By: | performance bug Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- I think we can probably do something like this, but I haven't checked the Core yet: {{{#!hs xs !! n | n < 0 = error "Prelude.!!: Negative index" | otherwise = foldr go (error "Prelude.!!: index too large or list empty") xs n where go x _ 0 = x go _ f k = f (k - 1) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9510> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9733: Strange errors when using type families as parameters
by GHC 28 Oct '14

28 Oct '14

#9733: Strange errors when using type families as parameters -------------------------------------+------------------------------------- Reporter: crockeea | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: GHC Blocked By: | rejects valid program Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- I seem to have found a dark corner of GHC. In the process of finding a minimal example, I found a few different ways to trigger a bug. I'm assuming they are all related. == Example 1 == I started off with a GADT parameterized by a type list: {{{#!haskell {-# LANGUAGE TypeFamilies, GADTs, DataKinds, TypeOperators #-} module Foo where type TList = '[Float, Double] type family PrevElt (xs :: [*]) (a :: *) :: * where PrevElt (b ': a ': xs) a = b PrevElt (b ': c ': xs) a = PrevElt (c ': xs) a data FooList :: ([*] -> * -> *) where Bar :: FooList prevrp ((PrevElt prevrp rp) -> rp) test1 :: FooList TList ((PrevElt TList rp) -> rp) test1 = Bar }}} which compiles as expected. If I make a syntactic change and parameterize the GADT with the type family rather than the type list: {{{#!hs {-# LANGUAGE TypeFamilies, GADTs, DataKinds, TypeOperators #-} module Foo where type TList = '[Float, Double] type family PrevElt (xs :: [*]) (a :: *) :: * where PrevElt (b ': a ': xs) a = b PrevElt (b ': c ': xs) a = PrevElt (c ': xs) a data FooTF :: ((* -> *) -> * -> *) where Bar :: FooTF prevrp ((prevrp rp) -> rp) test2 :: FooTF (PrevElt TList) ((PrevElt TList rp) -> rp) test2 = Bar }}} I get a non-sensical error: {{{ Foo.hs:15:9: Couldn't match type `PrevElt TList rp' with `PrevElt TList rp' NB: `PrevElt' is a type function, and may not be injective Expected type: FooTF (PrevElt TList) (PrevElt TList rp -> rp) Actual type: FooTF (PrevElt TList) (PrevElt TList rp -> rp) Relevant bindings include test2 :: FooTF (PrevElt TList) (PrevElt TList rp -> rp) (bound at testsuite\Foo.hs:15:1) In the expression: Bar In an equation for `test2': test2 = Bar }}} As far as I know, this should compile. == Example 2 == Another simple example uses [https://hackage.haskell.org/package/syntactic syntactic], along with the type-family-parameterized GADT: {{{#!hs {-# LANGUAGE TypeFamilies, GADTs, DataKinds, TypeOperators #-} module Foo where import Data.Syntactic type family PrevElt (xs :: [*]) (a :: *) :: * where PrevElt (b ': a ': xs) a = b PrevElt (b ': c ': xs) a = PrevElt (c ': xs) a data FooTF :: ((* -> *) -> * -> *) where Const :: FooTF prevrp (Full rp) Bar :: FooTF prevrp ((prevrp rp) :-> Full rp) type T1 = Double type T2 = Float type Dom = FooTF (PrevElt '[T1, T2]) leaf = inj (Const :: Dom (Full T1)) :: ASTF Dom T1 t1 = inj (Bar :: Dom (T1 :-> Full T2)) :$ leaf :: ASTF Dom T2 }}} By only changing the types `T1` and `T2`: {{{#!hs {-# LANGUAGE TypeFamilies, GADTs, DataKinds, TypeOperators #-} module Foo where import Data.Syntactic type family PrevElt (xs :: [*]) (a :: *) :: * where PrevElt (b ': a ': xs) a = b PrevElt (b ': c ': xs) a = PrevElt (c ': xs) a data FooTF :: ((* -> *) -> * -> *) where Const :: FooTF prevrp (Full rp) Bar :: FooTF prevrp ((prevrp rp) :-> Full rp) data T type T1 = T Double type T2 = T Float type Dom = FooTF (PrevElt '[T1, T2]) leaf = inj (Const :: Dom (Full T1)) :: ASTF Dom T1 t1 = inj (Bar :: Dom (T1 :-> Full T2)) :$ leaf :: ASTF Dom T2 }}} GHC complains: {{{ Foo.hs:21:11: Couldn't match type ‘Double’ with ‘T Float’ Expected type: Dom (T1 :-> Full T2) Actual type: FooTF T (T Double :-> Full Double) In the first argument of ‘inj’, namely ‘(Bar :: Dom (T1 :-> Full T2))’ In the first argument of ‘(:$)’, namely ‘inj (Bar :: Dom (T1 :-> Full T2))’ Failed, modules loaded: none. }}} == Example 3 == I've also attached a larger example (also using [https://hackage.haskell.org/package/syntactic syntactic]) that has [more, different] errors, which I believe to be related to this problem. Errors for the attached file are: {{{ Foo.hs:32:6: Couldn't match type `NextElt TList (PrevElt ((':) * (T' Float) ('[] *)) Double)' with `Double' Expected type: Double Actual type: NextElt TList (PrevElt TList Double) In the first argument of `(:$)', namely `inj' Bar' In the expression: inj' Bar :$ leaf In an equation for `t1': t1 = inj' Bar :$ leaf Foo.hs:32:11: Couldn't match type `PrevElt TList' with T' Expected type: Dom (Foo (T' Double) T1 :-> Full (Foo Double T1)) Actual type: FooTF T' (Foo (T' Double) T1 :-> Full (Foo Double T1)) In the first argument of inj', namely `Bar' In the first argument of `(:$)', namely `inj' Bar' }}} In the first error, the `Actual type: NextElt TList (PrevElt TList Double)` is strange because `Double` only occurs as a parameter to `T'`, and never as a naked type that could be applied to type family. In the second error, GHC seems to be confusing two types of kind `(* -> *)`: `T'` and `PrevElt TList`. Changing the GADT from type-family-indexed to type-list-index (like in the first example) makes the attached code compile. I minimized the attached example as much as possible: any changes I made to simplify the code resulted in different errors, which may also be helpful for finding this bug. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9733> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #2465: View + Pattern Match not fused sufficiently
by GHC 28 Oct '14

28 Oct '14

#2465: View + Pattern Match not fused sufficiently -------------------------------------+------------------------------------- Reporter: ryani | Owner: Type: bug | Status: new Priority: low | Milestone: ⊥ Component: Compiler | Version: 6.8.2 Resolution: | Keywords: Operating System: | Architecture: x86 Unknown/Multiple | Difficulty: Unknown Type of failure: Runtime | Blocked By: performance bug | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by gintas): * os: Windows => Unknown/Multiple -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2465#comment:8> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #989: Build GHC on Windows using Microsoft toolchain (was: Windows "native" port)
by GHC 28 Oct '14

28 Oct '14

#989: Build GHC on Windows using Microsoft toolchain -------------------------------------+------------------------------------- Reporter: simonmar | Owner: Type: feature | Status: new request | Milestone: ⊥ Priority: normal | Version: Component: Build | Keywords: System | Architecture: x86 Resolution: | Difficulty: Project (more Operating System: Windows | than a week) Type of failure: | Blocked By: None/Unknown | Related Tickets: Test Case: N/A | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by gintas): * difficulty: Difficult (2-5 days) => Project (more than a week) * type: task => feature request * component: Compiler => Build System -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/989#comment:14> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #110: Cygwin binaries
by GHC 28 Oct '14

28 Oct '14

#110: Cygwin binaries -------------------------------------+------------------------------------- Reporter: fizzgig | Owner: Type: feature | Status: new request | Milestone: ⊥ Priority: normal | Version: None Component: None | Keywords: Resolution: None | Architecture: Unknown/Multiple Operating System: Windows | Difficulty: Unknown Type of failure: | Blocked By: None/Unknown | Related Tickets: Test Case: N/A | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by gintas): Are we sure we still want this? Mingw binaries are generally preferred on Windows, and the current ghc Windows build is quite usable. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/110#comment:11> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #2628: hIsTerminalDevice returns True for /dev/null (aka NUL) on Windows
by GHC 28 Oct '14

28 Oct '14

#2628: hIsTerminalDevice returns True for /dev/null (aka NUL) on Windows -----------------------------------------+--------------------------- Reporter: igloo | Owner: ekmett Type: bug | Status: closed Priority: normal | Milestone: ⊥ Component: Core Libraries | Version: 6.8.3 Resolution: wontfix | Keywords: Operating System: Windows | Architecture: x86 Type of failure: None/Unknown | Difficulty: Unknown Test Case: 2228 | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -----------------------------------------+--------------------------- Changes (by gintas): * cc: core-libraries-committee@… (added) * status: new => closed * resolution: => wontfix Comment: The test passes here in an msys2 window, which is the new official ghc build environment. Closing. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2628#comment:5> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5305: crash after writing around 40 gigabytes to stdout
by GHC 28 Oct '14

28 Oct '14

#5305: crash after writing around 40 gigabytes to stdout -------------------------------------+------------------------------------- Reporter: lava | Owner: Type: bug | Status: infoneeded Priority: low | Milestone: 7.10.1 Component: Compiler | Version: 7.0.3 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: Runtime | Difficulty: Unknown crash | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by gintas): * status: new => infoneeded * difficulty: => Unknown -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5305#comment:7> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7191: hsc2hs can't treat absolute path correctly on Windows.
by GHC 28 Oct '14

28 Oct '14

#7191: hsc2hs can't treat absolute path correctly on Windows. -------------------------------------+------------------------------------- Reporter: shelarcy | Owner: Type: bug | Status: infoneeded Priority: normal | Milestone: Component: hsc2hs | Version: 7.8.1-rc2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: | Difficulty: Unknown None/Unknown | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by gintas): * status: new => infoneeded Comment: Can someone confirm? I just tried to reproduce the bug on 2014.2.0.0 but did not run into any problems. Absolute paths worked fine both from cmd.exe and from msys2 bash. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7191#comment:8> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9676: Data.List.isSuffixOf can be very inefficient
by GHC 28 Oct '14

28 Oct '14

#9676: Data.List.isSuffixOf can be very inefficient -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: ekmett Type: bug | Status: new Priority: normal | Milestone: 7.10.1 Component: Core Libraries | Version: 7.8.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Easy (less than 1 | Type of failure: Runtime hour) | performance bug Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- `Data.List.isSuffixOf` reverses both lists it is given. Thus, for example, {{{#!hs [12] `isSuffixOf` [1::Int .. (10^9)] }}} will build the complete list `[10^9, (10^9-1)..1]` in memory. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9676> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #2104: Add Labels
by GHC 28 Oct '14

28 Oct '14

#2104: Add Labels -------------------------------------+------------------------------------- Reporter: barney | Owner: Type: feature | Status: closed request | Milestone: 7.10.1 Priority: lowest | Version: 6.8.2 Component: Compiler | Keywords: Resolution: fixed | Architecture: Unknown/Multiple Operating System: | Difficulty: Unknown Unknown/Multiple | Blocked By: Type of failure: | Related Tickets: None/Unknown | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by barney): * status: new => closed * failure: => None/Unknown * resolution: => fixed Comment: I set this as fixed, because it's completely subsumed by Symbol. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2104#comment:15> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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