April 2016 - ghc-tickets

[GHC] #10333: hs-boot modification doesn't induce recompilation
by GHC 16 May '16

16 May '16

#10333: hs-boot modification doesn't induce recompilation -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC accepts Unknown/Multiple | invalid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- Consider these modules: X.hs-boot {{{ module X where }}} Y.hs {{{ module Y where import {-# SOURCE #-} X data T = T data S = S T }}} X.hs {{{ module X where import Y }}} `ghc --make Y.hs` will compile fine. Now, modify `X.hs-boot` to add a `data T` (which will cause an ambiguous identifier error in Y.hx`. Run `ghc --make Y.hs` and nothing happens! (You might also notice something else a bit funny, which is that `X.hs` gets compiled, even though it's not directly in the import chain of Y. I think this might be intentional but I'm not sure.) Discovered this while poking around #10182. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10333> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11768: Need a way to attach Haddock documentation to derived instances
by GHC 12 May '16

12 May '16

#11768: Need a way to attach Haddock documentation to derived instances -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: feature | Status: new request | Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 7.10.3 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: -------------------------------------+------------------------------------- In the case of `base` we'd like to be able to attach Haddock `@since` annotations on new typeclass instances. Unfortunately many instances are derived, which we can't currently attach Haddock documentation to. Fix this. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11768> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11099: Incorrect warning about redundant constraints
by GHC 12 May '16

12 May '16

#11099: Incorrect warning about redundant constraints -------------------------------------+------------------------------------- Reporter: diatchki | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 (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: -------------------------------------+------------------------------------- The following program results in an incorrect warning about a redundant constraint: {{{ {-# LANGUAGE TypeFamilies #-} type family SomeFun a f :: (SomeFun i ~ [a], Read a) => proxy i -> a f _ = read "HELLO" }}} This is the warning: {{{ Redundant constraint: SomeFun i ~ [a] In the type signature for: f :: (SomeFun i ~ [a], Read a) => proxy i -> a }}} I tried it on GHC version 7.11.20151029 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11099> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10181: Lint check: arity invariant
by GHC 11 May '16

11 May '16

#10181: Lint check: arity invariant -------------------------------------+------------------------------------- Reporter: nomeata | Owner: nomeata Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- The Arity of an ID should not exceed the arity of its type, nor the arity of its strictness signature, if it is a bottoming signatures. This should be checked by a lint check (suggested by SPJ in https://phabricator.haskell.org/D747?id=2498#inline-6058) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10181> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11746: I encountered an: internal error: evacuate: strange closure type 803645000
by GHC 11 May '16

11 May '16

#11746: I encountered an: internal error: evacuate: strange closure type 803645000 --------------------------------------+------------------------------- Reporter: hkBst | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 Keywords: | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: GHCi crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------------+------------------------------- I encountered an: internal error: evacuate: strange closure type 803645000 after loading and running the attached code under GHCi. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11746> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9478: Partial type signatures
by GHC 10 May '16

10 May '16

#9478: Partial type signatures -------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: | Differential Revisions: Phab:D168 -------------------------------------+------------------------------------- This ticket tracks progress on '''partial type signatures'''. * Wiki page [wiki:PartialTypeSignatures] * Phabricator link: Phab:D168 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9478> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11432: Cannot export operator newtype
by GHC 10 May '16

10 May '16

#11432: Cannot export operator newtype -------------------------------------+------------------------------------- Reporter: phadej | Owner: Type: bug | Status: new Priority: normal | Milestone: 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: -------------------------------------+------------------------------------- {{{#!hs {-# LANGUAGE TypeOperators #-} module Main (main, (-.->)(..)) where main :: IO () main = return () newtype (f -.-> g) a = Fn { apFn :: f a -> g a } }}} Fails to compile with {{{ [1 of 1] Compiling Main ( fn.hs, interpreted ) fn.hs:2:20: error: Not in scope: ‘-.->’ fn.hs:2:20: error: The export item ‘(-.->)(..)’ attempts to export constructors or class methods that are not visible here }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11432> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11961: PatBind test suite failure with `-DDEBUG`
by GHC 10 May '16

10 May '16

#11961: PatBind test suite failure with `-DDEBUG` -------------------------------------+------------------------------------- Reporter: nomeata | Owner: Type: bug | Status: new Priority: high | 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: -------------------------------------+------------------------------------- I get {{{ Compile failed (status 256) errors were: ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.1.20160420 for x86_64-unknown-linux): ASSERT failed! CallStack (from HasCallStack): assertPprPanic, called at compiler/types/TyCoRep.hs:2082:56 in ghc:TyCoRep checkValidSubst, called at compiler/types/TyCoRep.hs:2118:17 in ghc:TyCoRep substTy, called at compiler/types/TyCoRep.hs:2060:3 in ghc:TyCoRep in_scope InScope {a_apN t_apW a_apX} tenv [apC :-> t_apW[tau:3], apN :-> a_apX[tau:3]] tenvFVs [apD :-> t_apD[tau:3], apW :-> t_apW[tau:3], apX :-> a_apX[tau:3]] cenv [] cenvFVs [] tys [a_apN[sk] -> a_apN[sk]] cos [] Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug *** unexpected failure for PatBind(normal) }}} with a `-DDEBUG` build, e.g. on travis: https://s3.amazonaws.com/archive .travis-ci.org/jobs/124426776/log.txt -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11961> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11802: Make a Win32 release
by GHC 07 May '16

07 May '16

#11802: Make a Win32 release -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: task | Status: new Priority: high | Milestone: 8.0.1 Component: Compiler | Version: 8.0.1-rc3 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/11802> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11692: Suggest default definition of Applicative
by GHC 07 May '16

07 May '16

#11692: Suggest default definition of Applicative -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: GHCi | Version: 8.1 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: -------------------------------------+------------------------------------- {{{#!hs ghci> data A a = A a deriving (Show, Functor) ghci> instance Monad A <interactive>:3:10: error: • No instance for (Applicative A) arising from the superclasses of an instance declaration • In the instance declaration for ‘Monad A’ }}} could suggest defining it in terms of `Monad`: {{{#!hs <interactive>:3:10: error: • No instance for (Applicative A) arising from the superclasses of an instance declaration • In the instance declaration for ‘Monad A’ • Default implementation given a `Monad` instance: instance Applicative A where pure = return (<*>) = Control.Monad.ap }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11692> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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