May 2016 - ghc-tickets

[GHC] #10068: Make the runtime reflection API for names, modules, locations more systematic
by GHC 19 Mar '18

19 Mar '18

#10068: Make the runtime reflection API for names, modules, locations more systematic -------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: high | Milestone: 7.12.1 Component: Compiler | Version: 7.8.4 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Currently in `base` we have * `GHC.SrcLoc`: the data type `SrcLoc` contains `srcLocPackage` and `srcLocModule` * `Data.Typeable.Internals`: the data type `TyCon` contains `tyConPackage`, `tyConModule` and `tyConName. * `GHC.Generics`: the data type `Datatype` contains `dataTypePackage`, `dataTypeModule` and `dataTypeName` * `Data.Data`: the data type `DataType` (yes the capitalisation differs!) contains a field `tycon :: String`, and there are functions `tyconModule :: String -> String`, and `tyconUQname :: String -> String`, for parsing that string and extracting the module name and tycon name. * `GHC.StaticPtr`: the data type `StaticPtrInfo` contains `spInfoPackageKey`, `spInfoModuleName`, `spInfoName` (all `String`s). Oh, and `spInfoSrcLoc :: (Int,Int)` too! This is madness! Five different representations for the same information in one package! Let's fix this by defining some shared data types, for * `Module` = `ModuleName` + package * `Entity` = `Module` + unqualified name There would be a tiresome changeover period; but `Typeable` and `StaticPtr` are in flux anyway. Would anyone be willing to lead on this? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10068> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11382: Optimize Data.Char
by GHC 19 Mar '18

19 Mar '18

#11382: Optimize Data.Char -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Core | Version: 7.10.3 Libraries | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Runtime Unknown/Multiple | performance bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Many of the predicates in `Data.Char` do full Unicode category lookups which turns out to be quite expensive. Ideally we would handle some of the more common ASCII characters with cheaper tests before falling back to the full Unicode treatment. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11382> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11260: Re-compilation tests fail on powerpc64
by GHC 19 Mar '18

19 Mar '18

#11260: Re-compilation tests fail on powerpc64 -------------------------------------+------------------------------------- Reporter: trommler | Owner: trommler Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 7.11 Keywords: | Operating System: Linux Architecture: powerpc64 | Type of failure: Compile-time | performance bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- recomp011: {{{ [1 of 1] Compiling Main ( Main.hs, Main.o ) [A.hsinc changed] Linking Main ... 4343 +Linking Main ... 4343 }}} recomp015: {{{ [1 of 1] Compiling Main ( Main.hs, Main.o ) Linking Main ... Running main... +Linking Main ... Running main... }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11260> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11495: TH_spliceE5_prof is failing with release candidate 8.0.1
by GHC 19 Mar '18

19 Mar '18

#11495: TH_spliceE5_prof is failing with release candidate 8.0.1 -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 8.0.1-rc1 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: -------------------------------------+------------------------------------- `TH_spliceE5_prof` looks like this: {{{ TH_spliceE5_prof:: $(RM) TH_spliceE5_prof*.o TH_spliceE5_prof*.hi TH_spliceE5_prof*.dyn_o TH_spliceE5_prof*.dyn_hi TH_spliceE5_prof '$(TEST_HC)' $(TEST_HC_OPTS) $(HC_OPTS) $(ghcThWayFlags) --make -v0 TH_spliceE5_prof.hs -c '$(TEST_HC)' $(TEST_HC_OPTS) $(HC_OPTS) --make -v0 TH_spliceE5_prof.hs -prof -auto-all -osuf .p.o -o $@ ./$@ }}} In 4905b83a2d448c65ccced385343d4e8124548a3b, Simon added that `$(ghcThWayFlags)` to the first compilation command. With a release compiler, `ghcThWayFlags` defaults to `-dynamic`. But compiling with `-dynamic` doesn't produce `.dyn_o` files (you need `-dynamic-too` for that, which is enabled by `-XTemplateHaskell`, but **not** when compiling with `-dynamic`), so the second compilation results in: {{{ TH_spliceE5_prof.hs:8:17: fatal: cannot find object file ‘./TH_spliceE5_prof_Lib.dyn_o’ while linking an interpreted expression make[1]: *** [TH_spliceE5_prof] Error 1 *** unexpected failure for TH_spliceE5_prof(normal) }}} Not passing `-dynamic` fixes the test. But in the function `failNonStd` in `compiler/ghci/Linker.hs` Simon suggests that passing `-dynamic`: {{{ Cannot load -prof objects when GHC is built with -dynamic To fix this, either: (1) Use -fexternal-interprter, or (2) Build the program twice: once with -dynamic, and then with -prof using -osuf to set a different object file suffix. }}} Some ideas for a solution: * change that message to not mention `-dynamic` * always turn on `-dynamic-too` when `-XTemplateHaskell` is on, also when using `-dynamic` * find the place where `.dyn_o` is expected, and teach it that `.o` might also be ok. * make `-fexternal-interpreter` the default. Delete the test and a whole bunch of other stuff. It's all such a mess. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11495> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11827: InteractiveEval error handling gets a boot ModSummary instead of normal ModSummary
by GHC 19 Mar '18

19 Mar '18

#11827: InteractiveEval error handling gets a boot ModSummary instead of normal ModSummary -------------------------------------+------------------------------------- Reporter: darchon | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 8.0.1-rc3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Incorrect Unknown/Multiple | warning at compile-time Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Given: A.hs {{{#!hs module A where data A = A f :: A -> Bool f C = False }}} A.hs-boot {{{#!hs module A where data A f :: A -> Bool }}} B.hs {{{#!hs module B where import {-# SOURCE #-} A data B = B A g :: B -> Bool g (B a) = f a }}} ghci reports: {{{ $ ghci B.hs GHCi, version 8.0.0.20160411: http://www.haskell.org/ghc/ :? for help [1 of 3] Compiling A[boot] ( A.hs-boot, interpreted ) [2 of 3] Compiling A ( A.hs, interpreted ) A.hs:6:3: error: Not in scope: data constructor ‘C’ *** Exception: expectJust showModule CallStack (from HasCallStack): error, called at compiler/utils/Maybes.hs:48:27 in ghc:Maybes > }}} So instead of a normal error telling me that the C constructor does not exist, I get an additional exception from expectJust because something went wrong in GHCs internal error reporting routine. Looking at https://github.com/ghc/ghc/blob/master/compiler/main/InteractiveEval.hs#L956, the expectJust exception is due to the fact that while reporting an error about A.hs, GHCi somehow got a hold of the ModSummary of A.hs-boot instead of A.hs -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11827> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11773: linux/powepc : ghc-stage1 segfaults when building unregisterised
by GHC 19 Mar '18

19 Mar '18

#11773: linux/powepc : ghc-stage1 segfaults when building unregisterised --------------------------------+---------------------------------------- Reporter: erikd | Owner: erikd Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 8.1 Keywords: | Operating System: Unknown/Multiple Architecture: powerpc | Type of failure: Building GHC failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------+---------------------------------------- Building unregisterised to test code paths that don't get tested in the registerised compile mode. The segfault: {{{ "inplace/bin/ghc-stage1" -static -O -H64m -Wall -Iincludes -Iincludes/dist \ -Iincludes/dist-derivedconstants/header -Iincludes/dist- ghcconstants/header \ -Irts -Irts/dist/build -DCOMPILING_RTS -this-unit-id rts -optc-DNOSMP \ -dcmm-lint -i -irts -irts/dist/build -irts/dist/build/autogen \ -Irts/dist/build -Irts/dist/build/autogen -O2 -Wnoncanonical-monad- instances \ -c rts/StgStartup.cmm -o rts/dist/build/StgStartup.o }}} seems to occur on powerpc, but not on x86_64 or armhf. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11773> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11765: Allow documentary type signatures
by GHC 19 Mar '18

19 Mar '18

#11765: Allow documentary type signatures -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: Type: feature | Status: new request | Priority: normal | Milestone: 8.2.1 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: -------------------------------------+------------------------------------- In some cases (e.g., `lens`) it's useful to document a binding with a more specific type signature than the true one, to show a useful special case. Unfortunately, this documentation can potentially be wrong or go out of date. I'd like to propose a pragma for this: {{{#!hs {-# Documentary #-} f :: T -> U }}} would ask the type checker to verify that `f :: T -> U`. Specifically, it would have the effect of creating and type checking, but then discarding, a hidden binding {{{#!hs f_doc :: T -> U f_doc t = f t }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11765> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12038: Shutdown interacts badly with requestSync()
by GHC 19 Mar '18

19 Mar '18

#12038: Shutdown interacts badly with requestSync() -------------------------------------+------------------------------------- Reporter: simonmar | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Runtime | Version: 7.10.3 System | 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: -------------------------------------+------------------------------------- -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12038> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10774: Use `Natural` rather than `Integer` in `GHC.TypeLits`
by GHC 19 Mar '18

19 Mar '18

#10774: Use `Natural` rather than `Integer` in `GHC.TypeLits` -------------------------------------+------------------------------------- Reporter: hvr | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.12.1 Component: | Version: 7.10.2 libraries/base | Keywords: TypeLits | Operating System: Unknown/Multiple Natural | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- When the numeric type-literals were implement via `GHC.TypeLits` there was no `Natural` type in `base` yet. But since GHC 7.10 we finally have `Natural` available in base! Specifically, the following 3 type-signatures in `GHC.TypeLits` cpmtaom `Integer` that ought rather be `Natural`s: {{{#!hs someNatVal :: Integer -> Maybe SomeNat natVal :: forall n proxy. KnownNat n => proxy n -> Integer natVal' :: forall n. KnownNat n => Proxy# n -> Integer }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10774> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9671: Allow expressions in patterns
by GHC 16 Mar '18

16 Mar '18

#9671: Allow expressions in patterns -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.10.1 Component: Compiler | Version: Keywords: patterns, pattern | Operating System: synonyms | Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: Difficulty: Unknown | None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- I've outlined a proposal for extending pattern synonyms to depend on terms (PatternFamilies), the name is less than ideal but I'll keep the page under that name for now. The proposal's introduction has been rewritten. The simplest use case are patterns that matches only when a set contains an element (`IsMember`) or when a set does not contain an element (`NotMember`): [[Image(wiki:PatternFamilies:member.png)]] {{{#!hs hasKeys :: Set Item -> IO () hasKeys (IsMember "keys") = leaveHouse hasKeys (NotMember "keys") = findKeys >> leaveHouse }}} or a pattern that matches a map if the key exists: [[Image(wiki:PatternFamilies:lookup.png)]] used like this: {{{#!hs age :: Map Person Age -> String age (Lookup "Alice" 60) = "Alice is 60 years old!" age (Lookup "Alice" age) = "Alice is " ++ show age ++ "." age (Lookup "Bob" _) = "No info on Alice but we know how old Bob is." age _ = "..." }}} Further details and examples can be found here: PatternFamilies, I discussed it with several people ICFP 2014. This would not require a new extension but would extend PatternSynonyms. This feature can be quite useful, especially when working with deeply nested structures (ASTs, JSON, XML, ...). If people are fine with it I will implement it. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9671> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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