September 2015 - ghc-tickets

[GHC] #9699: TH function to list names in scope
by GHC 07 Mar '16

07 Mar '16

#9699: TH function to list names in scope -------------------------------------+------------------------------------- Reporter: MikeIzbicki | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: 7.8.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- I [asked about this on stackoverflow](http://stackoverflow.com/questions/26394199/using- templatehaskell-to-list-all-names-in-a-namespace), and apparently it doesn't exist yet. I want a TemplateHaskell function `variablesInScope :: Q [Name]` that returns a list of the `Name`'s of all the variables in scope. TemplateHaskell obviously has this information available in order to implement functions like `reify :: Name -> Q Info` and `lookupValueName :: String -> Q (Maybe Name)`. So it seems like this might be a pretty simple function to add. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9699> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10472: SigOf tests fail following renamer tidy-up
by GHC 01 Mar '16

01 Mar '16

#10472: SigOf tests fail following renamer tidy-up -------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- I'm about to commit a patch that fixes #7672. Sadly, though, it causes these failures {{{ driver/sigof02 sigof02dmt [bad stderr] (normal) driver/sigof02 sigof02dt [bad stderr] (normal) driver/sigof02 sigof02mt [bad exit code] (normal) driver/sigof02 sigof02t [bad exit code] (normal) }}} with errors like {{{ Main.hs:8:13: error: Can't find interface-file declaration for variable empty Probable cause: bug in .hi-boot file, or inconsistent .hi file Use -ddump-if-trace to get an idea of which file caused the error In the second argument of ‘($)’, namely ‘empty’ In the expression: insert 0 "foo" . delete 1 . insert 1 undefined . insert (6 :: Int) "foo" $ empty In an equation for ‘x’: x = insert 0 "foo" . delete 1 . insert 1 undefined . insert (6 :: Int) "foo" $ empty Main.hs:10:12: error: Can't find interface-file declaration for variable toList Probable cause: bug in .hi-boot file, or inconsistent .hi file Use -ddump-if-trace to get an idea of which file caused the error In the first argument of ‘print’, namely ‘(toList x)’ In a stmt of a 'do' block: print (toList x) In the expression: do { let x = insert 0 "foo" . delete 1 . insert 1 undefined . insert (6 :: Int) "foo" $ empty; print (member 1 x); print (toList x); print x } }}} Clearly there is only one bug here, and it's in the signature-handling code, which I do not fully understand. Happily, it's Edward's territory, and he is also involved in #7672. So I plan to mark these tests as broken on this ticket, and hope that Edward can adapt the signature stuff (which in any case is in-flight) to the new code. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10472> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10873: Bad error message for incorrect pattern synonym signature
by GHC 29 Feb '16

29 Feb '16

#10873: Bad error message for incorrect pattern synonym signature -------------------------------------+------------------------------------- Reporter: mpickering | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 7.10.2 (Type checker) | Keywords: newcomer | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- Consider the following program {{{ {-# LANGUAGE PatternSynonyms #-} pattern Pat :: Show a => () => a -> Maybe a pattern Pat a = Just a }}} GHC complains that {{{ test.hs:4:9: No instance for (Show a) arising from a pattern }}} I think this is quite difficult to understand. The problem is that matching on `Just a` doesn't provide the show constraint (it provides no constraints). A better error message here would explain this fact and maybe a short explanation of the difference between prov/req in a pattern synonym signature. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10873> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9043: Add missing type class instances for data types in GHC.Generics
by GHC 27 Feb '16

27 Feb '16

#9043: Add missing type class instances for data types in GHC.Generics ------------------------------------+------------------------------------- Reporter: ocharles | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: libraries/base | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- GHC.Generics offers a bunch of data types which have valid instances of various type classes in base, such as Functor. There's no good reason not to have these instances, so they should be added. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9043> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10316: Move Typeable type-rep generation from use site to definition site
by GHC 27 Feb '16

27 Feb '16

#10316: Move Typeable type-rep generation from use site to definition site -------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.12.1 Component: Compiler | Version: 7.10.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- This ticket is a continuation of #9858. The interim solution for 7.10 was to generate `Typeable` data structures on the fly, as needed in client modules. This ticket is about moving the generation of the runtime representation of type constructors to their definition sites. (#9858 already has too much going on in it, so I started a fresh ticket for this refactoring.) The branch is `wip/T9858-typeable-spj`. In favour of (A) code at use site (as in 7.10): * Pay as you go. No code at all is generated unless you use `Typeable` In favour of (B) code at definition site: * More sharing. We make a `TyCon` (see `Data.Typeable.Internal`) for `T` (say) just once, in the module that defines `T`. * We may ultimately want the `TyCon` for `T` to include its source location, and perhaps more besides. If it is defined in `T` it becomes easier to do that. General observation: (B) is like `Typeable` was before, when it was an ordinary class. The difference now is that all types are `Typeable`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10316> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8710: Overlapping patterns warning misplaced
by GHC 27 Feb '16

27 Feb '16

#8710: Overlapping patterns warning misplaced -------------------------+------------------------------------------------- Reporter: | Owner: goldfire | Status: new Type: bug | Milestone: Priority: low | Version: 7.7 Component: | Operating System: Unknown/Multiple Compiler | Type of failure: Incorrect warning at Keywords: | compile-time Architecture: | Test Case: Unknown/Multiple | Blocking: Difficulty: | Unknown | Blocked By: | Related Tickets: | -------------------------+------------------------------------------------- Consider {{{ {-# OPTIONS_GHC -fwarn-overlapping-patterns #-} len [] = 0 len (_:t) = 1 + len t len _ = error "urk" }}} GHC reports the problem with this definition at the first line of it. I think it would be more helpful to have it at the last line, which is the pattern that will never match. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8710> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9917: ddump-llvm runs opt/llc even when -fllvm isnt set
by GHC 27 Feb '16

27 Feb '16

#9917: ddump-llvm runs opt/llc even when -fllvm isnt set -------------------------------------+------------------------------------- Reporter: carter | 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: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- to reproduce put {{{ main= putStrLn "hello world" }}} in hello.hs and then invoke `ghc hello.hs -O2 -v3 -fforce-recomp -ddump-llvm` then at some point you'll see something like {{{ *** LLVM Optimiser: opt-3.4 /var/folders/py/wgp_hj9d2rl3cx48yym_ynj00000gn/T/ghc88460_0/ghc88460_2.ll -o /var/folders/py/wgp_hj9d2rl3cx48yym_ynj00000gn/T/ghc88460_0/ghc88460_4.bc -O2 '--enable-tbaa=true' *** LLVM Compiler: llc-3.4 -O2 '-relocation-model=pic' /var/folders/py/wgp_hj9d2rl3cx48yym_ynj00000gn/T/ghc88460_0/ghc88460_4.bc -o /var/folders/py/wgp_hj9d2rl3cx48yym_ynj00000gn/T/ghc88460_0/ghc88460_5.lm_s '--enable-tbaa=true' '-mattr=+sse2' *** LLVM Mangler: }}} in the output -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9917> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10217: Provide link to GPG signature on download page.
by GHC 25 Feb '16

25 Feb '16

#10217: Provide link to GPG signature on download page. -------------------------------------+------------------------------------- Reporter: f-a | Owner: Type: feature | Status: new request | Milestone: Priority: normal | Version: 7.10.1 Component: | Operating System: Unknown/Multiple Documentation | Type of failure: Documentation Keywords: GPG, | bug signature | Blocked By: Architecture: | Related Tickets: Unknown/Multiple | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- As now, in the section "Binary packages" of GHC download page, you can read: > SHA-256 hashes for all the binary distributions are available here. with a link to the hashes' file. It would be great to provide a link to the signature of this file too, i.e.: > SHA-256 hashes for all the binary distributions are available here[link] (GPG signature available here[link], signed with key <keyID>). Hashes and Signatures are advertised in the mailing list release post, but I guess it would be nice for clarity's sake having them on the download page too. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10217> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10336: Support qualified self {-# SOURCE #-} import
by GHC 25 Feb '16

25 Feb '16

#10336: Support qualified self {-# SOURCE #-} import -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: feature | Status: new request | Milestone: ⊥ Priority: lowest | Version: 7.11 Component: Compiler | Operating System: Unknown/Multiple Keywords: | Type of failure: GHC rejects Architecture: | valid program Unknown/Multiple | Blocked By: 7672 Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- The source import in this module is a no-op and has no legitimate use: {{{ module A where import {-# SOURCE #-} A }}} It's also tricky to support properly, see #10182. So we will disable it. However, there is one mode of use which cannot be legitimately done in normal Haskell: a qualified source import: {{{ module A where import {-# SOURCE #-} qualified A as MyA }}} The intended semantics is that the boot entities defined in A.hs-boot are available under the qualification MyA. Fixing #7672 would get us most of the way here, but there is one more step to avoid regressing #10182. So this just seems not worth fixing, unless someone really wants it. (Note: regular self imports could also be supported this way, but it would be even more complicated to do, since we don't even know what OccNames to add provenances for.) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10336> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10398: Support consecutive named Haddock comments
by GHC 25 Feb '16

25 Feb '16

#10398: Support consecutive named Haddock comments -------------------------------------+------------------------------------- Reporter: dmcclean | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1 (Parser) | Operating System: Unknown/Multiple Keywords: | Type of failure: Other Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- (I don't sufficiently understand the manner in which this arises from a GHC issue, but reliable sources inform me that it does.) This haddock issue, https://github.com/haskell/haddock/issues/392, apparently is related to the manner in which GHC parses comments. The way it manifests is that {{{#!hs module Foo ( -- $chunk1 -- $chunk2 foo, -- $chunk3 bar ) where {- $chunk1 This is chunk 1. -} {- $chunk2 This is chunk 2. -} {- $chunk3 This is chunk 3. -} foo = 3 bar = 7 }}} The resulting haddock documentation will include chunks 1 and 3 but not 2. See the linked ticket for a discussion by Mateusz Kowalczyk explaining how this relates to GHC. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10398> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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