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[GHC] #11220: Stack overflow instead of type check failure in Servant route
by GHC 15 Dec '15

15 Dec '15

#11220: Stack overflow instead of type check failure in Servant route -------------------------------------+------------------------------------- Reporter: sopvop | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 (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: -------------------------------------+------------------------------------- GHC 7.10.3 eats a lot of memory and segfaults compiling this. {{{#!hs {-# LANGUAGE DataKinds #-} {-# LANGUAGE EmptyDataDecls #-} {-# LANGUAGE TypeOperators #-} module Main where import Data.Proxy import Servant.API -- requires servant data A apiP :: Proxy Api apiP = Proxy -- Users type Api = "variants" :> Get '[JSON] () routeL :: URI routeL = safeLink apiP (Proxy :: Proxy ("variants" :> Get '[A] ())) -- Should result in type error -- '[JSON] in route but '[A] here main = print routeL }}} There is '[ JSON ] in Api type, but '[A] in Proxy type passed to safeLink, so it should result in type error. Correct program compiles without problems. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11220> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4426: Simplify the rules for implicit quantification
by GHC 15 Dec '15

15 Dec '15

#4426: Simplify the rules for implicit quantification -------------------------------------+------------------------------------- Reporter: simonpj | Owner: bgamari Type: feature request | Status: patch Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 6.12.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #7880 | Differential Rev(s): Phab:D211, Wiki Page: | Phab:D1615 -------------------------------------+------------------------------------- Changes (by bgamari): * status: new => patch * differential: Phab:D211 => Phab:D211, Phab:D1615 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4426#comment:27> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11202: T10667 is broken on OS X
by GHC 14 Dec '15

14 Dec '15

#11202: T10667 is broken on OS X -------------------------------------+------------------------------------- Reporter: bgamari | 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: -------------------------------------+------------------------------------- It fails with, {{{ =====> T10667(normal) 2 of 18 [0, 1, 0] cd ./codeGen/should_compile && "/Users/bgamari/ghc/inplace/test spaces /ghc-stage2" -c T10667.hs -fforce-recomp -dcore-lint -dcmm-lint -dno- debug-output -no-user-package-db -rtsopts -fno-warn-tabs -fno-warn-missed- specialisations -fno-ghci-history -g > T10667.comp.stderr 2>&1 Compile failed (status 256) errors were: /var/folders/4l/06tjh3z978l_b5plmkq08ff80000gq/T/ghc56547_0/ghc_1.s:101:2: error: error: unknown directive .hword 3 ^ /var/folders/4l/06tjh3z978l_b5plmkq08ff80000gq/T/ghc56547_0/ghc_1.s:129:2: error: error: unknown directive .hword 1 ^ /var/folders/4l/06tjh3z978l_b5plmkq08ff80000gq/T/ghc56547_0/ghc_1.s:131:2: error: error: unknown directive .hword 13 ^ . . . }}} [[https://developer.apple.com/library/mac/documentation/DeveloperTools/Refere…]] we should be using `.short` on Darwin. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11202> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11121: Introduce `-XTemplateHaskellQuotes` pragma for subset of TH
by GHC 14 Dec '15

14 Dec '15

#11121: Introduce `-XTemplateHaskellQuotes` pragma for subset of TH -------------------------------------+------------------------------------- Reporter: hvr | Owner: Type: feature | Status: new request | Priority: normal | Milestone: 8.0.1 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: #10382, #11102 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- TODO: describe why we need this -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11121> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10250: API Annotations : add Locations in hsSyn were layout occurs
by GHC 14 Dec '15

14 Dec '15

#10250: API Annotations : add Locations in hsSyn were layout occurs -------------------------------------+------------------------------------- Reporter: alanz | Owner: alanz Type: task | Status: new Priority: normal | Milestone: 7.10.2 Component: Compiler | Version: 7.10.1 Keywords: | Operating System: Unknown/Multiple ApiAnnotations | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- At the moment ghc-exactprint, which uses the GHC API Annotations to provide a framework for roundtripping Haskell source code with optional AST edits, has to implement a horrible workaround to manage the points where layout needs to be captured. These are MatchGroup HsDo HsCmdDo HsLet LetStmt HsCmdLet GRHSs To provide a more natural representation, the contents subject to layout rules need to be wrapped in a SrcSpan. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10250> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10238: Update libffi shortly before first GHC 7.12.1 RC
by GHC 14 Dec '15

14 Dec '15

#10238: Update libffi shortly before first GHC 7.12.1 RC -------------------------------------+------------------------------------- Reporter: hvr | Owner: hvr Type: task | Status: new Priority: highest | Milestone: 7.12.1 Component: Runtime | Version: System | Operating System: Unknown/Multiple Keywords: libffi | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Making this ticket so I don't forget to check for the latest libffi release shortly before the first RC (like I missed that "libffi-3.2.1 was released on November 12, 2014" which would have been in time for 7.10.1RC1) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10238> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10845: Incorrect behavior when let binding implicit CallStack object
by GHC 14 Dec '15

14 Dec '15

#10845: Incorrect behavior when let binding implicit CallStack object -------------------------------------+------------------------------------- Reporter: | Owner: nitromaster101 | Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- I'm trying out ghc HEAD at 062feee4e7408ad5b9d882e5fed2c700e337db72. {{{#!hs {-# LANGUAGE ImplicitParams #-} import GHC.Types f :: (?loc :: CallStack) => Int f = let y = length $ getCallStack ?loc in if y < 2 then 3 else 4 f2 :: (?loc :: CallStack) => Int f2 = if (length $ getCallStack ?loc) < 2 then 3 else 4 f3 :: (?loc :: [Int]) => Int f3 = let y = length ?loc in if y < 2 then 3 else 4 }}} produces: {{{ [1 of 1] Compiling Main ( Bug.hs, interpreted ) Bug.hs:5:6: warning: Redundant constraint: ?loc::CallStack In the type signature for: f :: (?loc::CallStack) => Int }}} f3 doesn't produce an error which makes me think it's related to CallStack handling. The warning seems accurate: the returned callstack only contains the entry at f. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10845> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10819: Can't generate data decls deriving multiparam type classes with TH
by GHC 14 Dec '15

14 Dec '15

#10819: Can't generate data decls deriving multiparam type classes with TH -------------------------------------+------------------------------------- Reporter: spinda | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Template | Version: 7.10.2 Haskell | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- This applies to both data declarations and (more commonly) newtypes. Example: {{{ {-# LANGUAGE GeneralizedNewtypeDeriving #-} newtype T a = X { unT :: State Int a } deriving (MonadState Int) }}} The newtype declaration is impossible to express in Template Haskell's AST, as the field for the derived classes is {{{[Name]}}} when it should really be {{{Cxt}}}. A workaround is to generate a {{{StandaloneDerivD}}} for each derived multiparam class, but this requires that the user enable the {{{StandaloneDeriving}}} extension which can be unintuitive, especially as there's no way (as far as I can tell) to detect whether this extension is enabled and report a proper error message if it isn't. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10819> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #3738: Typechecker floats stuff out of INLINE right hand sides
by GHC 14 Dec '15

14 Dec '15

#3738: Typechecker floats stuff out of INLINE right hand sides -------------------------------------+------------------------------------- Reporter: rl | Owner: igloo Type: bug | Status: closed Priority: normal | Milestone: 7.0.1 Component: Compiler | Version: 6.13 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: T3738 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Description changed by bgamari: Old description: > Small program: > {{{ > foo :: Num a => [a] -> a > {-# INLINE foo #-} > foo = go 0 > where > go m (n:ns) = m `seq` go (m+n) ns > go m [] = m > > bar :: [Int] -> Int > {-# INLINE bar #-} > bar = foo > }}} > Here is what `bar` looks like in the interface file: > {{{ > a6de4c46e53e565ed25ab5a38910e9cb > $wgo :: GHC.Prim.Int# -> [GHC.Types.Int] -> GHC.Prim.Int# > {- Arity: 2, HasNoCafRefs, Strictness: LS -} > 6838e3faa095285614477ebc92f54987 > bar :: [GHC.Types.Int] -> GHC.Types.Int > {- Arity: 1, HasNoCafRefs, Strictness: Sm, Inline: INLINE, > Unfolding: InlineRule: (arity 0 False) (Foo.bar_foo) -} > 5d06906ae99b9aefa1c6d251c3f2fc46 > bar_foo :: [GHC.Types.Int] -> GHC.Types.Int > {- Arity: 1, HasNoCafRefs, Strictness: Sm, > Unfolding: InlineRule: (arity 0 True) (\ w :: [GHC.Types.Int] -> > case @ GHC.Types.Int > Foo.$wgo 0 w of ww { DEFAULT -> > GHC.Types.I# ww }) -} > }}} > Note that the loop has disappeared from `bar`'s unfolding. Also, > `bar_foo` doesn't have an INLINE pragma. > > Incidentally, GHC specialises `foo` here and the specialisation doesn't > get an INLINE pragma, either: > {{{ > foo :: forall a. GHC.Num.Num a => [a] -> a > {- Arity: 1, HasNoCafRefs, Strictness: L, Inline: INLINE, > Unfolding: InlineRule: (arity 1 False) ... -} > > foo_$sfoo :: [GHC.Types.Int] -> GHC.Types.Int > {- Arity: 1, HasNoCafRefs, Strictness: Sm, > Unfolding: InlineRule: (arity 0 False) ... -} > > "SPEC Foo.foo [GHC.Types.Int]" ALWAYS forall $dNum :: GHC.Num.Num > GHC.Types.Int > Foo.foo @ GHC.Types.Int $dNum = Foo.foo_$sfoo > }}} New description: Small program: {{{#!hs foo :: Num a => [a] -> a {-# INLINE foo #-} foo = go 0 where go m (n:ns) = m `seq` go (m+n) ns go m [] = m bar :: [Int] -> Int {-# INLINE bar #-} bar = foo }}} Here is what `bar` looks like in the interface file: {{{ a6de4c46e53e565ed25ab5a38910e9cb $wgo :: GHC.Prim.Int# -> [GHC.Types.Int] -> GHC.Prim.Int# {- Arity: 2, HasNoCafRefs, Strictness: LS -} 6838e3faa095285614477ebc92f54987 bar :: [GHC.Types.Int] -> GHC.Types.Int {- Arity: 1, HasNoCafRefs, Strictness: Sm, Inline: INLINE, Unfolding: InlineRule: (arity 0 False) (Foo.bar_foo) -} 5d06906ae99b9aefa1c6d251c3f2fc46 bar_foo :: [GHC.Types.Int] -> GHC.Types.Int {- Arity: 1, HasNoCafRefs, Strictness: Sm, Unfolding: InlineRule: (arity 0 True) (\ w :: [GHC.Types.Int] -> case @ GHC.Types.Int Foo.$wgo 0 w of ww { DEFAULT -> GHC.Types.I# ww }) -} }}} Note that the loop has disappeared from `bar`'s unfolding. Also, `bar_foo` doesn't have an INLINE pragma. Incidentally, GHC specialises `foo` here and the specialisation doesn't get an INLINE pragma, either: {{{ foo :: forall a. GHC.Num.Num a => [a] -> a {- Arity: 1, HasNoCafRefs, Strictness: L, Inline: INLINE, Unfolding: InlineRule: (arity 1 False) ... -} foo_$sfoo :: [GHC.Types.Int] -> GHC.Types.Int {- Arity: 1, HasNoCafRefs, Strictness: Sm, Unfolding: InlineRule: (arity 0 False) ... -} "SPEC Foo.foo [GHC.Types.Int]" ALWAYS forall $dNum :: GHC.Num.Num GHC.Types.Int Foo.foo @ GHC.Types.Int $dNum = Foo.foo_$sfoo }}} -- -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3738#comment:10> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11053: Add a warning for pattern synonyms without signatures
by GHC 14 Dec '15

14 Dec '15

#11053: Add a warning for pattern synonyms without signatures -------------------------------------+------------------------------------- Reporter: mpickering | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 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 is accepted as good style that top-level definitions should have type signatures. Pattern synonyms seem no different to me in this regard so I think it would be good if GHC warned if there was a pattern synonym definition which lacked a type signature. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11053> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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