July 2017 - ghc-tickets

Re: [GHC] #5218: Add unpackCStringLen# to create Strings from string literals
by GHC 12 Jul '17

12 Jul '17

#5218: Add unpackCStringLen# to create Strings from string literals -------------------------------------+------------------------------------- Reporter: tibbe | Owner: thoughtpolice Type: feature request | Status: patch Priority: normal | Milestone: Component: Compiler | Version: 7.0.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: #5877 #10064 | Differential Rev(s): Phab:D2443 #11312 | Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * related: #5877 #10064 => #5877 #10064 #11312 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5218#comment:72> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12089: :kind command allows unsaturated type family,
by GHC 12 Jul '17

12 Jul '17

#12089: :kind command allows unsaturated type family, -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: 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: -------------------------------------+------------------------------------- {{{#!hs data A = B type family F a where F B = String infixr 9 `Compose` class (f (g x)) => (f `Compose` g) x instance (f (g x)) => (f `Compose` g) x }}} GHCi accepts {{{ ghci> :kind Compose Eq F Compose Eq F :: A -> Constraint }}} but when used in code it gets rejected {{{ -- tvI6.hs:13:8-33: error: … -- • The type family ‘F’ should have 1 argument, but has been given none -- • In the type signature: -- foo :: (Eq `Compose` F) a => String -- Compilation failed. foo :: (Eq`Compose`F) a => String foo = undefined }}} Bug? Version 8.0.0.20160511 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12089> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #605: Optimisation: strict enumerations
by GHC 12 Jul '17

12 Jul '17

#605: Optimisation: strict enumerations -------------------------------------+------------------------------------- Reporter: simonmar | Owner: (none) Type: task | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: None Resolution: None | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: N/A Blocked By: | Blocking: Related Tickets: #6135 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by tom-bop): * cc: tom-bop (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/605#comment:25> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8346: Rank 1 type signature still requires RankNTypes
by GHC 11 Jul '17

11 Jul '17

#8346: Rank 1 type signature still requires RankNTypes ----------------------------+---------------------------------------------- Reporter: | Owner: tinctorius | Status: new Type: bug | Milestone: Priority: normal | Version: 7.6.3 Component: Compiler | Operating System: Unknown/Multiple Keywords: | Type of failure: GHC rejects valid program Architecture: | Test Case: Unknown/Multiple | Blocking: Difficulty: Unknown | Blocked By: | Related Tickets: #2605 | ----------------------------+---------------------------------------------- When trying to figure out which type variable names are *actually* bound in `ScopedTypeVariables`, I tried floating `forall`s into the covariant argument of the function type. Essentially, I ran into the problem that programs like the following are rejected: {{{ #!hs {-# LANGUAGE ExplicitForAll #-} tuple :: forall a. a -> (forall b. b -> (a, b)) tuple = (,) }}} The message is as follows: {{{ Main.hs:2:10: Illegal polymorphic or qualified type: forall b. b -> (a, b) Perhaps you intended to use -XRankNTypes or -XRank2Types In the type signature for `tuple': tuple :: forall a. a -> (forall b. b -> (a, b)) }}} As far as I know, the rank of a type is defined by how deep quantifiers are nested in contravariant parts of that type. Or something like that. Also, as far as I know, `forall a. a -> (forall b. b -> (a, b))` is equivalent to `forall a b. a -> b -> (a, b)`, and more importantly, both are rank-1 polymorphic. There should be no need to use extensions that allow higher-ranked polymorphism. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8346> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13949: Haddock fails to typecheck an example with TemplateHaskell
by GHC 11 Jul '17

11 Jul '17

#13949: Haddock fails to typecheck an example with TemplateHaskell -------------------------------------+------------------------------------- Reporter: duog | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.3 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: -------------------------------------+------------------------------------- Reported by leftaroundabout at [https://github.com/haskell/haddock/issues/650] Surely this is a bug in GhcMake.enableCodegenForTH introduced in 53c78be0aab76a3107c4dacbb1d177afacdd37fa. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13949> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13818: ANN pragmas and -static fail to compile
by GHC 11 Jul '17

11 Jul '17

#13818: ANN pragmas and -static fail to compile -------------------------------------+------------------------------------- Reporter: duog | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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: -------------------------------------+------------------------------------- A Haskell source file with an ANN pragma will fail to compile with -static if any packages do not have dynamic libraries installed. Reproduction: {{{ $ echo "module Bug where {-# ANN module "just a string" #-}" > Bug.hs $ cabal sandbox init $ cabal install transformers-compat --disable-shared $ ghc -static -package db ./.cabal-sandbox/x86_64-linux- ghc-8.2.0.20170522-packages.conf.d -package transformers-compat -c Bug.hs <command line>: can't load .so/.DLL for: libHStransformers- compat-0.5.1.4-DQiwI4tzfvoKHf8rERr8Q2.so (libHStransformers- compat-0.5.1.4-DQiwI4tzfvoKHf8rERr8Q2.so: cannot open shared object file: No such file or directory) $ cabal install transformers-compat --enable-shared --reinstall $ ghc -static -package db ./.cabal-sandbox/x86_64-linux- ghc-7.10.3-packages.conf.d -package transformers-compat -c Bug.hs -fforce-recomp }}} Presumably the ANN pragma causes ghci to load with all libraries which must be dynamic. Not sure which category is correct for Type of failure. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13818> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13937: @progbits is used incorrectly throughout GHC
by GHC 11 Jul '17

11 Jul '17

#13937: @progbits is used incorrectly throughout GHC -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) 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: -------------------------------------+------------------------------------- GHC uses `.section $SECTION_NAME,$FLAGS,@progbits` directives throughout its produced assembler. However, some architectures (e.g. ARM) use `@` as a comment character and therefore must use some other prefix for section types. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13937> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13568: Name is reported as ambiguous and not in scope
by GHC 11 Jul '17

11 Jul '17

#13568: Name is reported as ambiguous and not in scope -------------------------------------+------------------------------------- Reporter: mpickering | Owner: (none) 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: -------------------------------------+------------------------------------- {{{ module A where data T = A }}} {{{ module B where import A data S = A foo :: A -> () foo = undefined }}} Compiling this example, the usage of `A` in `foo` is reported as both ambiguous and out of scope. I haven't mentioned data kinds at all so `A` should certainly refer to a type constructor which isn't in scope. The problem is that `DataKinds` is checked too late in `lookup_demoted`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13568> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13922: Sort output of failed tests.
by GHC 11 Jul '17

11 Jul '17

#13922: Sort output of failed tests. -------------------------------------+------------------------------------- Reporter: AndreasK | Owner: (none) Type: task | Status: new Priority: lowest | Milestone: Component: Test Suite | Version: 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: -------------------------------------+------------------------------------- The summary for failed tests can vary between runs. Sorting the output of {{{ "Unexpected results from: TEST="t1 t2..." }}} makes it easier to check for specific tests and to compare one run quickly with the result of another. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13922> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12390: List rules for `Coercible` instances
by GHC 11 Jul '17

11 Jul '17

#12390: List rules for `Coercible` instances -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: 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: -------------------------------------+------------------------------------- `:info` on [https://downloads.haskell.org/~ghc/7.8.2/docs/html/libraries/base-4.7.0.0 /Data-Coerce.html#t:Coercible Data.Coerce.Coercible] doesn't display any instances, it's a special class so it should be special-cased {{{ ghci> :i Coercible type role Coercible representational representational class a ~R# b => Coercible (a :: k) (b :: k) -- Defined in ‘GHC.Types’ }}} The base case would be easy to display: {{{#!hs instance Coercible a a -- Generated on the fly }}} but it's trickier to describe the … instance succinctly: {{{#!hs instance Coercible b b' => Coercible (D a b c) (D a b' c') }}} same for newtypes. ---- Maybe it's better to list concrete examples {{{#!hs coerce @(Reader _ _) :: Reader a b -> (a -> Identity b) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12390> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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