December 2015 - ghc-tickets

Re: [GHC] #229: Integer overflow in array allocation
by GHC 03 Dec '15

03 Dec '15

#229: Integer overflow in array allocation -------------------------------------+------------------------------------- Reporter: josefs | Owner: rwbarton Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Core Libraries | Version: 7.9 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Old description: > When asked to create a sufficiently large array ghci > coredumps. > > {{{#!hs > import Data.Array.ST > import Control.Monad.ST > import GHC.Base > > example = runST (do arr <- newArray (minInt,maxInt) False > go arr) > where go :: STArray s Int Bool -> ST s Bool > go arr = readArray arr 3 > }}} > > Load this into ghci and type 'example'. New description: When asked to create a sufficiently large array ghci coredumps. Edit: new example {{{#!hs import Data.Array.MArray import Data.Array.IO import Data.Word main = do m <- newArray_ (0,2^62-1) :: IO (IOUArray Int Word32) -- allocates 0 bytes writeArray m 17 12345 -- write wherever you like mapM (\x -> writeArray m x 0) [1..10000] -- core dump }}} Load this into ghci and type 'main'. -- Comment (by thomie): Update description with example from comment:15. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/229#comment:25> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7602: Threaded RTS performing badly on recent OS X (10.8?)
by GHC 03 Dec '15

03 Dec '15

#7602: Threaded RTS performing badly on recent OS X (10.8?) -------------------------------------+------------------------------------- Reporter: simonmar | Owner: thoughtpolice Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Runtime System | Version: Resolution: | Keywords: thread-local | state, TLS clang Operating System: MacOS X | Architecture: x86_64 Type of failure: Runtime | (amd64) performance bug | Test Case: Blocked By: 7678 | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * milestone: 8.0.1 => 8.2.1 Comment: thoughtpolice, do you have a patch for this? If not I'd say this won't happen for 8.0. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7602#comment:52> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #229: Integer overflow in array allocation
by GHC 03 Dec '15

03 Dec '15

#229: Integer overflow in array allocation -------------------------------------+------------------------------------- Reporter: josefs | Owner: rwbarton Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Core Libraries | Version: 7.9 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * cc: ekmett (added) Old description: > When asked to create a sufficiently large array ghci > coredumps. > > {{{ > \begin{code} > import Data.Array.ST > import Control.Monad.ST > import GHC.Base > > example = runST (do arr <- newArray (minInt,maxInt) > False > go arr) > where go :: STArray s Int Bool -> ST s Bool > go arr = readArray arr 3 > \end{code} > }}} > > Load this into ghci and type 'example'. New description: When asked to create a sufficiently large array ghci coredumps. {{{#!hs import Data.Array.ST import Control.Monad.ST import GHC.Base example = runST (do arr <- newArray (minInt,maxInt) False go arr) where go :: STArray s Int Bool -> ST s Bool go arr = readArray arr 3 }}} Load this into ghci and type 'example'. -- -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/229#comment:24> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8582: Record syntax for pattern synonyms
by GHC 03 Dec '15

03 Dec '15

#8582: Record syntax for pattern synonyms ------------------------------------+------------------------------------- Reporter: cactus | Owner: cactus Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: 5144 | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Implement syntax for {{{ pattern Cons{car, cdr} = (car, cdr) }}} which can then be used just like a regular record constructor, so the following are all valid patterns: {{{ Cons (Just x) [] Cons{car = Just x} }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8582> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #8440: Get rid of the remaining static flags
by GHC 03 Dec '15

03 Dec '15

#8440: Get rid of the remaining static flags -------------------------------------+------------------------------------- Reporter: thoughtpolice | Owner: siddhanathan Type: task | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * priority: high => normal * milestone: 8.0.1 => 8.2.1 Comment: This doesn't appear to be critical for 8.0. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8440#comment:5> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #322: fromInteger-related pattern match overlap warnings
by GHC 03 Dec '15

03 Dec '15

#322: fromInteger-related pattern match overlap warnings -------------------------------------+--------------------------------- Reporter: ashley-y | Owner: simonpj Type: bug | Status: closed Priority: normal | Milestone: ⊥ Component: Compiler | Version: 6.4 Resolution: duplicate | Keywords: warnings Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Test Case: ds060 Blocked By: | Blocking: Related Tickets: | -------------------------------------+--------------------------------- Comment (by George Karachalias <george.karachalias@…>): In [changeset:"8a506104d5b5b71d5640afc69c992e0af40f2213/ghc" 8a506104/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="8a506104d5b5b71d5640afc69c992e0af40f2213" Major Overhaul of Pattern Match Checking (Fixes #595) This patch adresses several problems concerned with exhaustiveness and redundancy checking of pattern matching. The list of improvements includes: * Making the check type-aware (handles GADTs, Type Families, DataKinds, etc.). This fixes #4139, #3927, #8970 and other related tickets. * Making the check laziness-aware. Cases that are overlapped but affect evaluation are issued now with "Patterns have inaccessible right hand side". Additionally, "Patterns are overlapped" is now replaced by "Patterns are redundant". * Improved messages for literals. This addresses tickets #5724, #2204, etc. * Improved reasoning concerning cases where simple and overloaded patterns are matched (See #322). * Substantially improved reasoning for pattern guards. Addresses #3078. * OverloadedLists extension does not break exhaustiveness checking anymore (addresses #9951). Note that in general this cannot be handled but if we know that an argument has type '[a]', we treat it as a list since, the instance of 'IsList' gives the identity for both 'fromList' and 'toList'. If the type is not clear or is not the list type, then the check cannot do much still. I am a bit concerned about OverlappingInstances though, since one may override the '[a]' instance with e.g. an '[Int]' instance that is not the identity. * Improved reasoning for nested pattern matching (partial solution). Now we propagate type and (some) term constraints deeper when checking, so we can detect more inconsistencies. For example, this is needed for #4139. I am still not satisfied with several things but I would like to address at least the following before the next release: Term constraints are too many and not printed for non-exhaustive matches (with the exception of literals). This sometimes results in two identical (in appearance) uncovered warnings. Unless we actually show their difference, I would like to have a single warning. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/322#comment:12> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #3078: Erroneous warnings for -XPatternGuards
by GHC 03 Dec '15

03 Dec '15

#3078: Erroneous warnings for -XPatternGuards ------------------------------+------------------------------- Reporter: guest | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 6.10.1 Resolution: duplicate | Keywords: Operating System: Linux | Architecture: x86_64 (amd64) Test Case: | ------------------------------+------------------------------- Comment (by George Karachalias <george.karachalias@…>): In [changeset:"8a506104d5b5b71d5640afc69c992e0af40f2213/ghc" 8a506104/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="8a506104d5b5b71d5640afc69c992e0af40f2213" Major Overhaul of Pattern Match Checking (Fixes #595) This patch adresses several problems concerned with exhaustiveness and redundancy checking of pattern matching. The list of improvements includes: * Making the check type-aware (handles GADTs, Type Families, DataKinds, etc.). This fixes #4139, #3927, #8970 and other related tickets. * Making the check laziness-aware. Cases that are overlapped but affect evaluation are issued now with "Patterns have inaccessible right hand side". Additionally, "Patterns are overlapped" is now replaced by "Patterns are redundant". * Improved messages for literals. This addresses tickets #5724, #2204, etc. * Improved reasoning concerning cases where simple and overloaded patterns are matched (See #322). * Substantially improved reasoning for pattern guards. Addresses #3078. * OverloadedLists extension does not break exhaustiveness checking anymore (addresses #9951). Note that in general this cannot be handled but if we know that an argument has type '[a]', we treat it as a list since, the instance of 'IsList' gives the identity for both 'fromList' and 'toList'. If the type is not clear or is not the list type, then the check cannot do much still. I am a bit concerned about OverlappingInstances though, since one may override the '[a]' instance with e.g. an '[Int]' instance that is not the identity. * Improved reasoning for nested pattern matching (partial solution). Now we propagate type and (some) term constraints deeper when checking, so we can detect more inconsistencies. For example, this is needed for #4139. I am still not satisfied with several things but I would like to address at least the following before the next release: Term constraints are too many and not printed for non-exhaustive matches (with the exception of literals). This sometimes results in two identical (in appearance) uncovered warnings. Unless we actually show their difference, I would like to have a single warning. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3078#comment:2> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #2204: Improve 'patterns not matched' warnings
by GHC 03 Dec '15

03 Dec '15

#2204: Improve 'patterns not matched' warnings -------------------------------------+------------------------------------- Reporter: Deewiant | Owner: Type: feature request | Status: closed Priority: low | Milestone: ⊥ Component: Compiler | Version: 6.8.2 Resolution: duplicate | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): -------------------------------------+------------------------------------- Comment (by George Karachalias <george.karachalias@…>): In [changeset:"8a506104d5b5b71d5640afc69c992e0af40f2213/ghc" 8a506104/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="8a506104d5b5b71d5640afc69c992e0af40f2213" Major Overhaul of Pattern Match Checking (Fixes #595) This patch adresses several problems concerned with exhaustiveness and redundancy checking of pattern matching. The list of improvements includes: * Making the check type-aware (handles GADTs, Type Families, DataKinds, etc.). This fixes #4139, #3927, #8970 and other related tickets. * Making the check laziness-aware. Cases that are overlapped but affect evaluation are issued now with "Patterns have inaccessible right hand side". Additionally, "Patterns are overlapped" is now replaced by "Patterns are redundant". * Improved messages for literals. This addresses tickets #5724, #2204, etc. * Improved reasoning concerning cases where simple and overloaded patterns are matched (See #322). * Substantially improved reasoning for pattern guards. Addresses #3078. * OverloadedLists extension does not break exhaustiveness checking anymore (addresses #9951). Note that in general this cannot be handled but if we know that an argument has type '[a]', we treat it as a list since, the instance of 'IsList' gives the identity for both 'fromList' and 'toList'. If the type is not clear or is not the list type, then the check cannot do much still. I am a bit concerned about OverlappingInstances though, since one may override the '[a]' instance with e.g. an '[Int]' instance that is not the identity. * Improved reasoning for nested pattern matching (partial solution). Now we propagate type and (some) term constraints deeper when checking, so we can detect more inconsistencies. For example, this is needed for #4139. I am still not satisfied with several things but I would like to address at least the following before the next release: Term constraints are too many and not printed for non-exhaustive matches (with the exception of literals). This sometimes results in two identical (in appearance) uncovered warnings. Unless we actually show their difference, I would like to have a single warning. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2204#comment:8> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4139: Spurious non-exhaustive pattern match warnings are given using GADTs
by GHC 03 Dec '15

03 Dec '15

#4139: Spurious non-exhaustive pattern match warnings are given using GADTs -------------------------------------+------------------------------------- Reporter: blarsen | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.4.1 Resolution: duplicate | Keywords: GADTs, warnings, | pattern matching Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: Incorrect | Test Case: warning at compile-time | Blocked By: | Blocking: Related Tickets: #3927 | -------------------------------------+------------------------------------- Comment (by George Karachalias <george.karachalias@…>): In [changeset:"8a506104d5b5b71d5640afc69c992e0af40f2213/ghc" 8a506104/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="8a506104d5b5b71d5640afc69c992e0af40f2213" Major Overhaul of Pattern Match Checking (Fixes #595) This patch adresses several problems concerned with exhaustiveness and redundancy checking of pattern matching. The list of improvements includes: * Making the check type-aware (handles GADTs, Type Families, DataKinds, etc.). This fixes #4139, #3927, #8970 and other related tickets. * Making the check laziness-aware. Cases that are overlapped but affect evaluation are issued now with "Patterns have inaccessible right hand side". Additionally, "Patterns are overlapped" is now replaced by "Patterns are redundant". * Improved messages for literals. This addresses tickets #5724, #2204, etc. * Improved reasoning concerning cases where simple and overloaded patterns are matched (See #322). * Substantially improved reasoning for pattern guards. Addresses #3078. * OverloadedLists extension does not break exhaustiveness checking anymore (addresses #9951). Note that in general this cannot be handled but if we know that an argument has type '[a]', we treat it as a list since, the instance of 'IsList' gives the identity for both 'fromList' and 'toList'. If the type is not clear or is not the list type, then the check cannot do much still. I am a bit concerned about OverlappingInstances though, since one may override the '[a]' instance with e.g. an '[Int]' instance that is not the identity. * Improved reasoning for nested pattern matching (partial solution). Now we propagate type and (some) term constraints deeper when checking, so we can detect more inconsistencies. For example, this is needed for #4139. I am still not satisfied with several things but I would like to address at least the following before the next release: Term constraints are too many and not printed for non-exhaustive matches (with the exception of literals). This sometimes results in two identical (in appearance) uncovered warnings. Unless we actually show their difference, I would like to have a single warning. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4139#comment:10> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #3927: Incomplete/overlapped pattern warnings + GADTs = inadequate
by GHC 03 Dec '15

03 Dec '15

#3927: Incomplete/overlapped pattern warnings + GADTs = inadequate -------------------------------------+------------------------------------- Reporter: simonpj | Owner: simonpj Type: bug | Status: closed Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 6.12.1 Resolution: duplicate | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #4139 | Differential Rev(s): -------------------------------------+------------------------------------- Comment (by George Karachalias <george.karachalias@…>): In [changeset:"8a506104d5b5b71d5640afc69c992e0af40f2213/ghc" 8a506104/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="8a506104d5b5b71d5640afc69c992e0af40f2213" Major Overhaul of Pattern Match Checking (Fixes #595) This patch adresses several problems concerned with exhaustiveness and redundancy checking of pattern matching. The list of improvements includes: * Making the check type-aware (handles GADTs, Type Families, DataKinds, etc.). This fixes #4139, #3927, #8970 and other related tickets. * Making the check laziness-aware. Cases that are overlapped but affect evaluation are issued now with "Patterns have inaccessible right hand side". Additionally, "Patterns are overlapped" is now replaced by "Patterns are redundant". * Improved messages for literals. This addresses tickets #5724, #2204, etc. * Improved reasoning concerning cases where simple and overloaded patterns are matched (See #322). * Substantially improved reasoning for pattern guards. Addresses #3078. * OverloadedLists extension does not break exhaustiveness checking anymore (addresses #9951). Note that in general this cannot be handled but if we know that an argument has type '[a]', we treat it as a list since, the instance of 'IsList' gives the identity for both 'fromList' and 'toList'. If the type is not clear or is not the list type, then the check cannot do much still. I am a bit concerned about OverlappingInstances though, since one may override the '[a]' instance with e.g. an '[Int]' instance that is not the identity. * Improved reasoning for nested pattern matching (partial solution). Now we propagate type and (some) term constraints deeper when checking, so we can detect more inconsistencies. For example, this is needed for #4139. I am still not satisfied with several things but I would like to address at least the following before the next release: Term constraints are too many and not printed for non-exhaustive matches (with the exception of literals). This sometimes results in two identical (in appearance) uncovered warnings. Unless we actually show their difference, I would like to have a single warning. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3927#comment:44> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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