January 2014 - ghc-tickets

[GHC] #8656: Identical functions in Templeta Haskell
by GHC 10 Jan '14

10 Jan '14

#8656: Identical functions in Templeta Haskell -------------------------------------------+------------------------------- Reporter: jstolarek | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: 7.7 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Easy (less than 1 hour) | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: -------------------------------------------+------------------------------- I noticed that module `Language.Haskell.TH.Lib` in template-haskell library contains duplicate functions: {{{ global :: Name -> ExpQ global s = return (VarE s) varE :: Name -> ExpQ varE s = return (VarE s) }}} If this is intended it should be documented why it is so and I think it would be good to express one function in terms of another. If this is accidental we should just get rid of one function. I never used TH so I have no idea whether this is done on purpose or not, thus leaving it to devs more experienced with TH. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8656> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8651: 'Untouchable' error when using type function in class constraint in rank-2 type
by GHC 10 Jan '14

10 Jan '14

#8651: 'Untouchable' error when using type function in class constraint in rank-2 type -------------------------------------------+------------------------------- Reporter: sbarclay | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type checker) | Version: 7.7 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: #8644 #7594 | Test Case: | Blocking: -------------------------------------------+------------------------------- I noticed there are some cases that no longer compile after the recent fix for #8644, such as the following: {{{#!haskell {-# LANGUAGE RankNTypes, FlexibleContexts, TypeFamilies #-} import Data.Monoid type family Id a type instance Id a = a --type instance Id [a] = [Id a] foo :: (Monoid (Id String) => r) -> r foo x = x main :: IO () main = print $ foo "Hello" }}} Attempting to compile this on HEAD produces the same error in 'main' as reported in the earlier ticket: {{{ Couldn't match expected type ‛s0’ with actual type ‛[Char]’ ‛s0’ is untouchable }}} However, it compiles fine if the commented-out type family instance is used instead. It also compiles fine if the type family is replaced with an ordinary type synonym: {{{#!haskell type Id a = a }}} I guess that the problem is caused by equalities of the form t ~ [Char] introduced by the type family instance. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8651> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5498: Generalized newtype deriving allows creating of instances I can't create by hand
by GHC 10 Jan '14

10 Jan '14

#5498: Generalized newtype deriving allows creating of instances I can't create by hand -----------------------------------------------+--------------------------- Reporter: dterei | Owner: Type: bug | Status: closed Priority: normal | Milestone: 7.6.2 Component: Compiler | Version: 7.3 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Test Case: deriving/should_fail/T5498 | Difficulty: Unknown Blocking: | Blocked By: 1496 | Related Tickets: -----------------------------------------------+--------------------------- Comment (by Simon Peyton Jones <simonpj@…>): In [changeset:"1285af76c32c84332835d5d430146403bf610796/testsuite"]: {{{ #!CommitTicketReference repository="testsuite" revision="1285af76c32c84332835d5d430146403bf610796" Test Trac #5498 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5498#comment:11> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8644: 'Untouchable' error with constraint variable in rank-2 type
by GHC 10 Jan '14

10 Jan '14

#8644: 'Untouchable' error with constraint variable in rank-2 type -------------------------------------+------------------------------------- Reporter: sbarclay | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 7.7 checker) | Operating System: Unknown/Multiple Keywords: | Type of failure: GHC rejects Architecture: Unknown/Multiple | valid program Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | -------------------------------------+------------------------------------- The following program compiles fine with GHC 7.6.3: {{{#!haskell {-# LANGUAGE ConstraintKinds, RankNTypes, GADTs #-} data Dict c where Dict :: c => Dict c foo :: Dict c -> (c => r) -> r foo Dict x = x bar :: Dict () bar = Dict main :: IO () main = print $ foo bar "Hello" }}} However, it produces the following error with HEAD: {{{ ConstraintIssue.hs:12:8: No instance for (Show s0) arising from a use of ‛print’ The type variable ‛s0’ is ambiguous Note: there are several potential instances: instance Show Double -- Defined in ‛GHC.Float’ instance Show Float -- Defined in ‛GHC.Float’ instance (Integral a, Show a) => Show (GHC.Real.Ratio a) -- Defined in ‛GHC.Real’ ...plus 24 others In the expression: print In the expression: print $ foo bar "Hello" In an equation for ‛main’: main = print $ foo bar "Hello" ConstraintIssue.hs:12:24: Couldn't match expected type ‛s0’ with actual type ‛[Char]’ ‛s0’ is untouchable inside the constraints (()) bound by a type expected by the context: (()) => s0 at ConstraintIssue.hs:12:16-30 In the second argument of ‛foo’, namely ‛"Hello"’ In the second argument of ‛($)’, namely ‛foo bar "Hello"’ In the expression: print $ foo bar "Hello" }}} If the type signature of 'main' is removed, the code compiles OK. If the empty constraint () is replaced with an equality constraint such as Int ~ Int, then the above error occurs with both 7.6.3 and HEAD, which I guess is intended behaviour. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8644> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7021: Tuple (and other exotic predicates) not yet handled in Template Haskell
by GHC 10 Jan '14

10 Jan '14

#7021: Tuple (and other exotic predicates) not yet handled in Template Haskell -------------------------+------------------------------------------------- Reporter: | Owner: goldfire | Status: new Type: | Milestone: 7.8.1 feature request | Version: 7.5 Priority: | Keywords: ConstraintKinds normal | TemplateHaskell Component: | Architecture: Unknown/Multiple Template Haskell | Difficulty: Unknown Resolution: | Blocked By: Operating System: | Related Tickets: Unknown/Multiple | Type of failure: | None/Unknown | Test Case: | Blocking: | -------------------------+------------------------------------------------- Comment (by goldfire): Do you have patches posted somewhere? And I'm surprised that you didn't have to modify `compiler/deSugar/DsMeta.lhs` to get this working -- that file handles translation of TH quotes, which should support the new kinds of predicates. Where is your test case? Have you run the testsuite? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7021#comment:7> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8659: GHCi told me to tell you that it crashed
by GHC 10 Jan '14

10 Jan '14

#8659: GHCi told me to tell you that it crashed ------------------------------+------------------------------------- Reporter: ishkabible | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 7.4.2 Keywords: | Operating System: Unknown/Multiple Architecture: x86 | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------+------------------------------------- I'm using an x86 build of GHCi version 7.4.2 on Windows 7 professional. I attempted to interpret the following code and GHC crashed and told me to report the issue. {{{ module ConstructorTypes where import Data.List (intercalate) import VarGenMonad data ConstructorSpec = Spec { parrentType :: ConstructorSpec, specName :: String, specArgs :: [Type] } deriving(Eq, Ord) data ConstructorTypeSpec = ConTypeSpec { conTypeName :: String, conSpecs :: [ConstructorSpec], numParams :: Int } data Pattern = Pat ConstructorSpec [Pattern] | Id String deriving(Eq, Ord) --this holds data Type = Poly Type | DeBruijnTypeVar Int | ConType ConstructorTypeSpec | Type :-> Type deriving(Eq, Ord, show) --define Eq and Ord to break infinte chain of type/spec/type/spec/... instance Eq ConstructorTypeSpec where t1 == t2 = conTypeName t1 == conTypeName t2 instance Ord ConstructorTypeSpec where t1 <= t2 = conTypeName t1 <= conTypeName t2 --create own show types to give a nice syntax and avoid infinite loops instance Show ConstructorSpec where show (Spec ty name args) = name ++ (concatMap ((' ':) . show) args) ++ " :: " ++ conTypeName ty instance Show ConstructorTypeSpec where show (ConTypeSpec name specs vars) = name ++ "=" ++ (concatMap (("\n\t" ++) . show) specs) genUniqueVars lst n = take n $ runVarGen lst gen where gen = do x <- drawVar return $ x : gen {-- toString env (Poly t) = do a <- drawVar --should advance to next varible b <- toString (a:env) t --any calls to drawVar in toString should advance it as well return $ "(forall " ++ a ++ ")" ++ b toString env (DeBruijn x) = do return $ env !! x --no changes are made here however toString env (ConType spec) = do names <- mapM_ (toString env) (typeVars spec) --each call to drawVar in each call toString should advance the internal state return $ conTypeName spec ++ intercalate " " names toString env (x :-> y) = do t1 <- toString env x t2 <- toString env y return $ "(" ++ t1 ++ ") -> " ++ t2 --} }}} "VarGenMonad" is the following code {{{ module VarGenMonad (VarGen, runVarGen, runVarGenWith, drawVar) where import Control.Monad --effectivlly a state monad of type State a [String] newtype VarGen a = VarGen { getFunc :: [String] -> (a, [String]) } --just gets the resulting value (this is what users will interface to) runVarGen vl vg = runVarGenWith showInt where showInt 0 = "" showInt x = show x --another function the user can interacte with runVarGenWith f vl vg = fst $ runState vg (makeVarListWith f vl) --gets the result from a var gen monad after telling it what varibles to use runState :: VarGen a -> [String] -> (a, [String]) runState vg vl = (getFunc vg) vl --creates an infinte list of unique varibles from a finite one makeVarListWith :: Integral a => (a -> String) -> [String] -> [String] makeVarListWith f lst = gen lst lst 0 where gen t [] c = gen t t (c + 1) gen t (x:xs) c = (x ++ f c) : gen t xs c --implements the monad operations in same fashion as a state monad instance Monad VarGen where return x = VarGen $ \s -> (x, s) cur >>= transform = VarGen func where func s = runState (transform v) nextList where (v, nextList) = runState cur s drawVar :: VarGen String drawVar = VarGen $ \(x:xs) -> (x, xs) }}} this worked before I added "show" (note that it is lowercase cuz I messed up) to the deriving cluase of my 'Type' type. After fixing it to make it an upper case S GHC promptly told me what else I had messed up in my code (that is, it worked correctly). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8659> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7021: Tuple (and other exotic predicates) not yet handled in Template Haskell
by GHC 09 Jan '14

09 Jan '14

#7021: Tuple (and other exotic predicates) not yet handled in Template Haskell -------------------------+------------------------------------------------- Reporter: | Owner: goldfire | Status: new Type: | Milestone: 7.8.1 feature request | Version: 7.5 Priority: | Keywords: ConstraintKinds normal | TemplateHaskell Component: | Architecture: Unknown/Multiple Template Haskell | Difficulty: Unknown Resolution: | Blocked By: Operating System: | Related Tickets: Unknown/Multiple | Type of failure: | None/Unknown | Test Case: | Blocking: | -------------------------+------------------------------------------------- Comment (by yoeight): Thanks for your advices ! I made Pred a type synonym of TH.Type. Impacted files sum up: {{{ dph-lifted-copy/Data/Array/Parallel/Lifted/TH/Repr.hs compiler/hsSyn/Convert.lhs compiler/typecheck/TcSplice.lhs Language/Haskell/TH.hs Language/Haskell/TH/Lib.hs Language/Haskell/TH/Ppr.hs Language/Haskell/TH/Syntax.hs }}} I have also made a test case based on description snippet Yorick -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7021#comment:6> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7942: aarch64 support in ghc
by GHC 09 Jan '14

09 Jan '14

#7942: aarch64 support in ghc --------------------------------------------+--------------------------- Reporter: jcapik | Owner: kgardas Type: feature request | Status: new Priority: normal | Milestone: 7.10.1 Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Operating System: Linux | Architecture: arm Type of failure: GHC doesn't work at all | Difficulty: Unknown Test Case: | Blocked By: 7623 Blocking: | Related Tickets: --------------------------------------------+--------------------------- Comment (by carter): @karel, step 1 of that link says "make sure the unregisterized C build works" :) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7942#comment:18> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7942: aarch64 support in ghc
by GHC 09 Jan '14

09 Jan '14

#7942: aarch64 support in ghc --------------------------------------------+--------------------------- Reporter: jcapik | Owner: kgardas Type: feature request | Status: new Priority: normal | Milestone: 7.10.1 Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Operating System: Linux | Architecture: arm Type of failure: GHC doesn't work at all | Difficulty: Unknown Test Case: | Blocked By: 7623 Blocking: | Related Tickets: --------------------------------------------+--------------------------- Comment (by kgardas): Replying to [comment:16 carter]: > @karel, > unregisterized builds use GCC specific C code, in which case you'll have to use GCC. > > GCC 4.8 and newer, when built with multi target support, seems to have aarch 64 support. > > clang/llvm wont work. > > cheers > -Carter Carter, this is misunderstanding IMHO. I'm not dealing with unregisterised via C, but instead with unregisterised via LLVM build here. Please read the GHC/LLVM porting document I linked above for more information. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7942#comment:17> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7942: aarch64 support in ghc
by GHC 09 Jan '14

09 Jan '14

#7942: aarch64 support in ghc --------------------------------------------+--------------------------- Reporter: jcapik | Owner: kgardas Type: feature request | Status: new Priority: normal | Milestone: 7.10.1 Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Operating System: Linux | Architecture: arm Type of failure: GHC doesn't work at all | Difficulty: Unknown Test Case: | Blocked By: 7623 Blocking: | Related Tickets: --------------------------------------------+--------------------------- Comment (by carter): @karel, unregisterized builds use GCC specific C code, in which case you'll have to use GCC. GCC 4.8 and newer, when built with multi target support, seems to have aarch 64 support. clang/llvm wont work. cheers -Carter -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7942#comment:16> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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