May 2017 - ghc-tickets

[GHC] #13271: GHC Panic With Injective Type Families
by GHC 12 May '17

12 May '17

#13271: GHC Panic With Injective Type Families ----------------------------------------+--------------------------------- Reporter: wayofthepie | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Linux Architecture: Unknown/Multiple | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ----------------------------------------+--------------------------------- The following causes GHC to panic: {{{ {-# LANGUAGE DataKinds #-} {-# LANGUAGE TypeFamilyDependencies #-} module T where import GHC.TypeLits data T1 = T1 type T2 = TypeError (Text "You can't do that!") type family X i = r | r -> i where X 1 = T1 X 2 = T2 }}} {{{ $ ghc T.hs [1 of 1] Compiling T ( T.hs, T.o ) ghc: panic! (the 'impossible' happened) (GHC version 8.0.1 for x86_64-unknown-linux): isInjectiveTyCon sees a TcTyCon T2 }}} This may be related to https://ghc.haskell.org/trac/ghc/ticket/11560. Without injectivity it gives the expected type error with the message "You can't do that!" {{{ {-# LANGUAGE DataKinds #-} {-# LANGUAGE TypeFamilies #-} module T where import GHC.TypeLits data T1 = T1 type T2 = TypeError (Text "You can't do that!") type family X i where X 1 = T1 X 2 = T2 }}} {{{ $ ghc T.hs [1 of 1] Compiling T ( T.hs, T.o ) T.hs:9:1: error: • You can't do that • In the type synonym declaration for ‘T2’ }}} This isn't something anyone would intentionally write, as it could never type check with the type synonym T2 being a TypeError, but a panic is a panic so I said I'd raise it anyway. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13271> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13545: Remove duplication between lookupSubBndrOcc and lookupExportChild
by GHC 11 May '17

11 May '17

#13545: Remove duplication between lookupSubBndrOcc and lookupExportChild -------------------------------------+------------------------------------- Reporter: mpickering | Owner: (none) Type: task | 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: -------------------------------------+------------------------------------- `lookupSubBndrOcc` is used in expressions such as `x { y = 5 }` to resolve field labels such as `y`. `lookupExportChild` is used in export lists such as `T(A, x)` to lookup `A` and `x`. They contain very similar logic but it is duplicated in two places which caused #13528. It should be easy to refactor them them to deduplicate the logic. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13545> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13688: Allow splices in definition of pattern synonym
by GHC 11 May '17

11 May '17

#13688: Allow splices in definition of pattern synonym -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Template | Version: 8.0.1 Haskell | Keywords: | Operating System: Unknown/Multiple PatternSynonyms | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- shlevy requests the ability to write, {{{#!hs pattern MyUUID = [uuid|dbf20a11-b04a-47a5-a7d6-a6f9ae7ff895|] }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13688> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13417: piResultTys1
by GHC 11 May '17

11 May '17

#13417: piResultTys1 -------------------------------------+------------------------------------- Reporter: ralf | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Compile-time (amd64) | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Error provoked by attached H98 program (which is generated by a program); compiles fine without optimizations; compilation with -O2 crashes: $ ghc --make -O2 FactorialSequ.lhs [1 of 1] Compiling FactorialSequ ( FactorialSequ.lhs, FactorialSequ.o ) ghc: panic! (the 'impossible' happened) (GHC version 8.0.2 for x86_64-unknown-linux): piResultTys1 Sequ7 t_a2zl [a_a2zm] -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13417> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11722: No TypeRep for unboxed tuples
by GHC 11 May '17

11 May '17

#11722: No TypeRep for unboxed tuples -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 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: -------------------------------------+------------------------------------- This now crashes on GHC HEAD: {{{#!hs {-# LANGUAGE MagicHash #-} {-# LANGUAGE UnboxedTuples #-} module Main where import Data.Typeable import GHC.Exts main :: IO () main = print $ typeOf (Proxy :: Proxy (# Int, Int #)) }}} {{{ $ /opt/ghc/head/bin/ghc -O2 -fforce-recomp Example.hs [1 of 1] Compiling Main ( Example.hs, Example.o ) ghc: panic! (the 'impossible' happened) (GHC version 8.1.20160317 for x86_64-unknown-linux): tyConRep (#,#) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} (Previously, this was rejected with an error message, since you couldn't put an unlifted type as the argument of `Proxy`.) (Copied from comment:28:ticket:11471.) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11722> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9450: GHC instantiates Data instances before checking hs-boot files
by GHC 11 May '17

11 May '17

#9450: GHC instantiates Data instances before checking hs-boot files -------------------------------------+------------------------------------- Reporter: alanz | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Keywords: boot,deriving | Operating System: Architecture: x86_64 (amd64) | Unknown/Multiple Difficulty: Unknown | Type of failure: Compile- Blocked By: | time crash Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- When compiling a file with deriving instances in it and making use of boot files, it appears that the derivation is attempted before the boot files are checked for consistency. This can lead to GHC panics, as when compiling GHC after this commit https://github.com/alanz/ghc/commit/c73182ca7345f0debba47d0b17a907bcac27c41f In the attached files, if you try to load HsLit.lhs into ghci it will complain about the missing Data instance, not about the boot file inconsistency. If you remove the Data from the deriving clause of HsOverLit, it complains about the boot file inconsistency. I have not managed to reproduce the original panic in this stripped down environment, but if it is needed to more fully understand the problem I can try again to do that. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9450> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13686: Compile a few modules for profiling unconditionally
by GHC 11 May '17

11 May '17

#13686: Compile a few modules for profiling unconditionally -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: 8.4.1 Component: Build System | 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: -------------------------------------+------------------------------------- When GHC is built without enabling profiling of the libraries, it is utterly impossible to compile anything ''with'' profiling. I would like to compile just enough libraries with profiling, unconditionally, to be able to compile any module with profiling as long as it satisfies approximately three conditions: 1. It uses `NoImplicitPrelude`. 2. It does not import any modules from a boot package. 3. It does not use `TemplateHaskell` (I'm not sure if this is necessary, but I wouldn't be surprised if it were). To make this work, I think we would need to compile at least `GHC.Types` and the `Data.Typeable.Internal` for profiling in all cases. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13686> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5777: core lint error with arrow notation and GADTs
by GHC 11 May '17

11 May '17

#5777: core lint error with arrow notation and GADTs -------------------------------------+------------------------------------- Reporter: benmos | Owner: ross Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 7.4.2 checker) | Keywords: arrows, Resolution: | GADTs, Arrows Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash | Test Case: Blocked By: | Blocking: Related Tickets: #13547 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * related: => #13547 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5777#comment:17> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13685: ghc: panic
by GHC 11 May '17

11 May '17

#13685: ghc: panic -------------------------------------+------------------------------------- Reporter: Iceland_jack | 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: -------------------------------------+------------------------------------- A friendly compiler asked me to report {{{#!hs {-# Language KindSignatures, TypeInType, MagicHash #-} module A where import Data.Kind import GHC.Types i :: (a :: TYPE DoubleRep) -> a i x = x main = print (D# (i 3.0##)) }}} panics {{{ $ ghci -ignore-dot-ghci /tmp/A.hs GHCi, version 8.0.1: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling A ( /tmp/A.hs, interpreted ) ghc: panic! (the 'impossible' happened) (GHC version 8.0.1 for x86_64-unknown-linux): getIdFromTrivialExpr 3.0## Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13685> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12850: Panic with unboxed integers and ghci
by GHC 11 May '17

11 May '17

#12850: Panic with unboxed integers and ghci -------------------------------------+------------------------------------- Reporter: monoidal | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: GHCi crash Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Attempting to load the following file in ghci causes a panic in getIdFromTrivialExpr. Tested in GHC 8.0.1 and HEAD. {{{ {-# LANGUAGE ExplicitForAll, MagicHash, KindSignatures #-} import GHC.Types (RuntimeRep(..), TYPE) f :: forall (x :: TYPE 'IntRep). x -> x f x = x g = () where h = f 0# }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12850> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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