December 2013 - ghc-tickets

[GHC] #8266: Dynamic linking on Mac
by GHC 04 Feb '15

04 Feb '15

#8266: Dynamic linking on Mac ------------------------------+-------------------------------------------- Reporter: kazu- | Owner: yamamoto | Status: new Type: bug | Milestone: Priority: highest | Version: 7.7 Component: Build | Operating System: MacOS X System | Type of failure: GHC doesn't work at all Keywords: | Test Case: Architecture: | Blocking: Unknown/Multiple | Difficulty: Unknown | Blocked By: | Related Tickets: | ------------------------------+-------------------------------------------- Many dynamic libraries refer to the build tree. (1) Every ".dylib" installed with GHC head refers to itself in its build directory. E.g. {{{ % otool -L libHSbase-4.7.0.0-ghc7.7.20130909.dylib | grep base libHSbase-4.7.0.0-ghc7.7.20130909.dylib: /Users/kazu/work/ghc/libraries/base/dist- install/build/libHSbase-4.7.0.0-ghc7.7.20130909.dylib (compatibility version 0.0.0, current version 0.0.0) }}} (2) Some ".dylib" installed with GHC head refers to other libraries in their build directories. E.g. {{{ % otool -L libHSvector-0.9.1-ghc7.7.20130909.dylib | grep /Users /Users/kazu/work/ghc/libraries/vector/dist- install/build/libHSvector-0.9.1-ghc7.7.20130909.dylib (compatibility version 0.0.0, current version 0.0.0) /Users/kazu/work/ghc/libraries/primitive/dist- install/build/libHSprimitive-0.4.0.1-ghc7.7.20130909.dylib (compatibility version 0.0.0, current version 0.0.0) }}} (3) All user installed libraries by cabal-install refer to other libraries in their build directories. E.g. {{{ % otool -L libHSghc-paths-0.1.0.9-ghc7.7.20130909.dylib| grep Users /Users/kazu/Library/Haskell/ghc-7.7.20130909/lib/ghc- paths-0.1.0.9/lib/libHSghc-paths-0.1.0.9-ghc7.7.20130909.dylib (compatibility version 0.0.0, current version 0.0.0) /Users/kazu/work/ghc/libraries/base/dist- install/build/libHSbase-4.7.0.0-ghc7.7.20130909.dylib (compatibility version 0.0.0, current version 0.0.0) /Users/kazu/work/ghc/libraries/integer-gmp/dist-install/build /libHSinteger-gmp-0.5.1.0-ghc7.7.20130909.dylib (compatibility version 0.0.0, current version 0.0.0) /Users/kazu/work/ghc/libraries/ghc-prim/dist-install/build /libHSghc-prim-0.3.1.0-ghc7.7.20130909.dylib (compatibility version 0.0.0, current version 0.0.0) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8266> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8624: -ddump-splices-file
by GHC 19 Jan '15

19 Jan '15

#8624: -ddump-splices-file ------------------------------------+------------------------------------- Reporter: GregWeber | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- I am proposing an additional feature, `-ddump-splices-file` that generates a corresponding `.hs.th` file for every `.hs` file that uses Template Haskell. `-ddump-splices` is an invaluable but a frustrating way to look at generated Haskell code. If TH generation were some kind of error message, the current output would make sense. However, TH is generating code that we rely on and would be easier to comprehend if we could see it in a way the most similar to our existing Haskell code. There is a valid complaint that when TH defines something you can't just grep for it, you have to know what TH is defining by reading documentation and imagining something that isn't in front of you. If you have a file `Foo.hs` `-ddump-splices-file` will generate `Foo.hs.th`. Then whenever someone greps after buliding they will find the declaration. If you check these files in they can grep even before building. Similarly, an IDE can show these files as the source of a declaration. Also, if the TH generation changes in some way when a TH function changes, that will be visible. This seems like a relatively easy feature to add. Any pointers on where to get started? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8624> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8486: cannot derive new-typeable instances for promoted data types taking parameters
by GHC 07 Jan '15

07 Jan '15

#8486: cannot derive new-typeable instances for promoted data types taking parameters ------------------------------------+------------------------------------- Reporter: aavogt | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Hi, The following code shows the issue: {{{ {-# LANGUAGE DataKinds, DeriveDataTypeable, KindSignatures, PolyKinds, StandaloneDeriving #-} import Data.Typeable import GHC.TypeLits data T (a :: [*]) = T deriving (Typeable) t = T :: T [Int, Double] deriving instance Typeable '[] {- *Main> typeOf t <interactive>:24:1: No instance for (Typeable (* -> [*] -> [*]) ((':) *)) arising from a use of ‛typeOf’ In the expression: typeOf t In an equation for ‛it’: it = typeOf t -} }}} ghc7.7-20131004 doesn't allow either of the following: {{{ deriving instance (Typeable a, Typeable b) => Typeable (a ': b) -- or deriving instance Typeable (':) }}} On ghc-7.6 I could write my own `instance Typeable (T a)`, but this has been disabled it seems. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8486> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8525: lib/integer/integerConstantFolding fails with -DDEBUG
by GHC 17 Dec '14

17 Dec '14

#8525: lib/integer/integerConstantFolding fails with -DDEBUG -------------------------------+------------------------------------------- Reporter: nomeata | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Test Suite | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: integerConstantFolding Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | -------------------------------+------------------------------------------- Hi, with `-DDEBUG` in `GhcStage2HcOpts`, the test integerConstantFolding fails: {{{ =====> integerConstantFolding(normal) 1103 of 3814 [0, 1, 0] cd ./lib/integer && $MAKE -s --no-print-directory integerConstantFolding </dev/null >integerConstantFolding.run.stdout 2>integerConstantFolding.run.stderr Actual stderr output differs from expected: --- /dev/null 2013-11-12 10:54:14.804286745 +0100 +++ ./lib/integer/integerConstantFolding.run.stderr 2013-11-12 15:33:12.384669953 +0100 @@ -0,0 +1,62 @@ +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl{v r3Ok} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl4{v r3Oo} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl8{v r3Os} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl12{v r3Ow} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + ww1{v r3OO} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl48{v r3P7} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl52{v r3Pb} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl56{v r3Pf} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl60{v r3Pj} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl64{v r3Pn} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl68{v r3Pr} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + ww2{v r3Pv} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + ww3{v r3Pw} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + ww4{v r3PG} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + ww5{v r3PH} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl90{v r3PR} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl94{v r3PV} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl98{v r3PZ} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl102{v r3Q3} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl106{v r3Q7} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl110{v r3Qb} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl134{v r3Qz} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl138{v r3QD} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl142{v r3QH} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl146{v r3QL} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl153{v r3QS} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl161{v r3R0} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl165{v r3R4} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl169{v r3R8} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl173{v r3Rc} [gid] True False +WARNING: file compiler/stgSyn/CoreToStg.lhs, line 269 + lvl177{v r3Rg} [gid] True False *** unexpected failure for integerConstantFolding(normal) }}} The warning is in `consistentCafInfo` source:compiler/stgSyn/CoreToStg.lhs and was was last touched by SPJ in [fdf86568], and originally introduced by simmonmar in 2e6d322e130a8c37807a14699bbcbf9eb08fc970. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8525> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8584: Pattern synonym type signatures
by GHC 17 Dec '14

17 Dec '14

#8584: Pattern synonym type signatures ------------------------------------+------------------------------------- Reporter: cactus | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: 5144 | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Currently, the only way to specify a type signature for a pattern synonym is by adding type annotations to the right-hand side, like this: {{{ {-# LANGUAGE PatternSynonyms, ScopedTypeVariables #-} pattern Single x = ([x] :: [Int]) }}} Bespoke syntax for adding type signatures for pattern synonyms would probably be useful. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8584> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8240: Better error messages for type family constraints
by GHC 11 Dec '14

11 Dec '14

#8240: Better error messages for type family constraints ------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Consider this constraint {{{ F Int ~ Bool -- Arising (say) on line 5 F Int ~ Char -- Arising (say) on line 10 }}} At the moment we'll combine the two to {{{ F Int ~ Bool -- Arising on line 5 Bool ~ Char -- Arising on line 10 }}} The second of these errors is "insoluble" and is reported first. But it's totally misleading: nowhere in the program did we directly need `Int~Char`. Another variant of this came up in Trac #8227. There we get the constraint {{{ Scalar (V a) ~ t0 Scalar (V a) ~ t0 -> t0 }}} which leads to {{{ Scalar (V a) ~ t0 -> t0 t0 ~ t0 -> t0 -- Occurs check }}} which gives the confusing error {{{ T8227.hs:16:44: Occurs check: cannot construct the infinite type: t0 ~ t0 -> t0 Expected type: Scalar (V (t0 -> t0)) Actual type: Scalar (V a) }}} I think the solution is * Do not combine two Wanteds {{{ [W] F tys ~ t1 [W] F tys ~ t2 }}} unless t1 and t2 are both touchable unification variables. * Instead (perhaps) generate a Derived constraint {{{ [D] t1 ~ t2 }}} to express the fact that t1 and t2 had better end up equal. * To do this the inert set would need to contain many `CTyFunEq` constraints with the same LHS. I'm not very sure about this, and no time now, so I'm just making this ticket to record the issue. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8240> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8548: Coercible does not resolve type family application
by GHC 02 Dec '14

02 Dec '14

#8548: Coercible does not resolve type family application -------------------------------------------+------------------------------- Reporter: nomeata | Owner: nomeata Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type checker) | Version: 7.6.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: #8503 | Test Case: | Blocking: -------------------------------------------+------------------------------- With GND implemented using `Coercible` (See #8503) the test for #4185 fails. A minimal example is: {{{ {-# LANGUAGE TypeFamilies #-} module CoerceNewtypeFamily where import GHC.Exts data family Foo k newtype instance Foo Int = FooInt Int x :: Foo Int -> Int x = coerce }}} yielding {{{ [1 of 1] Compiling CoerceNewtypeFamily ( CoerceNewtypeFamily.hs, CoerceNewtypeFamily.o ) CoerceNewtypeFamily.hs:11:5: No instance for (Coercible (Foo Int) Int) because ‛Foo Int’ and ‛Int’ are different types. arising from a use of ‛coerce’ In the expression: coerce In an equation for ‛x’: x = coerce }}} I guess the `Coercible` finding code needs to simply type family equations if possible. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8548> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8304: more lenient operator sections (RelaxedSections extension)
by GHC 01 Dec '14

01 Dec '14

#8304: more lenient operator sections (RelaxedSections extension) -------------------------------------+------------------------------------- Reporter: aavogt | Owner: Type: feature request | Status: new Priority: lowest | Milestone: Component: Compiler (Parser) | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | -------------------------------------+------------------------------------- Some operator sections are rejected which could have some meaning. {{{ (a ++ b ++ ) could mean \x -> a ++ b ++ c (++ a ++) could mean \x y -> x ++ a ++ y }}} The attached quasiquoter implements this, but for various reasons it would be better if ghc supported this directly. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8304> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8100: Standalone deriving using template haskell
by GHC 01 Dec '14

01 Dec '14

#8100: Standalone deriving using template haskell ------------------------------------+------------------------------------- Reporter: acube | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Currently, there seems to be no support for standalone deriving in TemplateHaskell: {{{ Prelude Data.Typeable Language.Haskell.TH> :set -XStandaloneDeriving Prelude Data.Typeable Language.Haskell.TH> data Weird a (b :: * -> * -> *) c = Weird Prelude Data.Typeable Language.Haskell.TH> runQ $ [d| deriving instance Typeable Weird |] [] }}} ''Use case'': The library [http://hackage.haskell.org/package/typeable-th typeable-th] can already generate Typeable instances using TH for GHC 7.4 and 7.6. To add support for GHC 7.8 in a way that the user doesn't have to care about the version, there has to be a way to make Typeable instances via TH in GHC 7.8. This is currently impossible, but with StandaloneDeriving support for TH, it would be possible. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8100> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8323: explore ways to possibly use more tag bits in x86_64 pointers
by GHC 28 Nov '14

28 Nov '14

#8323: explore ways to possibly use more tag bits in x86_64 pointers ------------------------------------+------------------------------------- Reporter: carter | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- on x86_64, pointers only use 48 bits! currently we use 3bits for tagging / arity etc info on x86_64, we should explore more uses! -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8323> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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