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[GHC] #9033: Type error suppresses defaulting, causes spurious errors
by GHC 28 Apr '14

28 Apr '14

#9033: Type error suppresses defaulting, causes spurious errors -----------------------------------------+--------------------------------- Reporter: jun0 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: defaulting, ambiguous | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: -----------------------------------------+--------------------------------- I have a strong feeling this must have been reported already but I can't find a ticket for it, so here goes. If a source file contains a type error, like {{{#!haskell bad :: Bool bad = () }}} then GHC seems to turn off defaulting for ambiguous types in the remainder of the file. So if the same file contains for instance {{{#!haskell square :: Integral i => i -> i square x = x^2 }}} then GHC reports another type error at the ^2: {{{ test.hs:4:7: Couldn't match expected type ‘Bool’ with actual type ‘()’ In the expression: () In an equation for ‘bad’: bad = () test.hs:7:13: Could not deduce (Integral b0) arising from a use of ‘^’ from the context (Integral i) bound by the type signature for square :: Integral i => i -> i at test.hs:6:11-30 The type variable ‘b0’ is ambiguous Note: there are several potential instances: instance Integral Int -- Defined in ‘GHC.Real’ instance Integral Integer -- Defined in ‘GHC.Real’ instance Integral GHC.Types.Word -- Defined in ‘GHC.Real’ In the expression: x ^ 2 In an equation for ‘square’: square x = x ^ 2 test.hs:7:14: Could not deduce (Num b0) arising from the literal ‘2’ from the context (Integral i) bound by the type signature for square :: Integral i => i -> i at test.hs:6:11-30 The type variable ‘b0’ is ambiguous Note: there are several potential instances: instance Num Double -- Defined in ‘GHC.Float’ instance Num Float -- Defined in ‘GHC.Float’ instance Integral a => Num (GHC.Real.Ratio a) -- Defined in ‘GHC.Real’ ...plus three others In the second argument of ‘(^)’, namely ‘2’ In the expression: x ^ 2 In an equation for ‘square’: square x = x ^ 2 }}} The first error is a legitimate type mismatch and it's all fine, but the other two should be resolved with default instance selection -- and it is, once the type error in `bad` is fixed. For example, rewriting `bad` to {{{#!haskell bad :: () bad = () }}} makes *all* errors go away, including the ones on `square`. Default instance selection seems to be turned back on when square is made monomorphic, like {{{#!haskell squareMono :: Int -> Int squareMono x = x^2 }}} Note that the type of x is being fixed, not the 2 that GHC complains about in square. The effect of this is that in a file with a large number of `^2`, `^3`, and such, the error message pointing to the real type error is drowned in all the "could not deduce" messages. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9033> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9036: ghc: panic! (the 'impossible' happened) (Binder's type (SingI Symbol <a String>) /= RHS type (String))
by GHC 28 Apr '14

28 Apr '14

#9036: ghc: panic! (the 'impossible' happened) (Binder's type (SingI Symbol <a String>) /= RHS type (String)) --------------------------------+--------------------------------------- Reporter: ntc2 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: GHC.TypeLits | Operating System: Linux Architecture: x86 | Type of failure: Compile-time crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | --------------------------------+--------------------------------------- Compilation error message: {{{ ghc: panic! (the 'impossible' happened) (GHC version 7.6.3 for i386-unknown-linux): cgLookupPanic (probably invalid Core; try -dcore-lint) cobox{v a212} [lid] static binds for: local binds for: main:Debug.Trace.LogTree.Test.$p1AllShow{v r1pg} [gid[ClassOp]] main:Debug.Trace.LogTree.Test.$p2AllShow{v r1ph} [gid[ClassOp]] main:Debug.Trace.LogTree.Test.$p3AllShow{v r1pi} [gid[ClassOp]] main:Debug.Trace.LogTree.Test.$p4AllShow{v r1pj} [gid[ClassOp]] main:Debug.Trace.LogTree.Test.$p5AllShow{v r1pk} [gid[ClassOp]] main:Debug.Trace.LogTree.Test.$p6AllShow{v r1pl} [gid[ClassOp]] Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} Error in -dcore-lint: {{{ [10 of 10] Compiling Debug.Trace.LogTree.Test ( src/Debug/Trace/LogTree/Test.hs, tmp/Debug/Trace/LogTree/Test.o ) *** Core Lint errors : in result of Desugar (after optimization) *** {-# LINE 122 "src/Debug/Trace/LogTree/Test.hs #-}: Warning: [RHS of $dSingI_a20r :: GHC.TypeLits.SingI GHC.TypeLits.Symbol "h"] The type of this binder doesn't match the type of its RHS: $dSingI_a20r Binder's type: GHC.TypeLits.SingI GHC.TypeLits.Symbol "h" Rhs type: [GHC.Types.Char] }}} So, it looks like it's related to !TypeLits. The full -dcore-lint output is attached. To reproduce: 1. git clone https://github.com/ntc2/haskell-call-trace.git 2. cd haskell-call-trace 3. git checkout break-ghc 3. <install dependencies; see below> 4. make The dependencies from the .cabal file are: {{{ build-depends: base >=4.6 && <4.7 , template-haskell >=2.8 && <2.9 , ghc-prim >=0.3 && <0.4 , parsec >=3.1 && <3.2 , tagged >=0.7 && <0.8 , transformers >=0.3 && <0.4 , mtl >=2.1 && <2.2 }}} The problematic file is https://github.com/ntc2/haskell-call-trace/blob /break-ghc/src/Debug/Trace/LogTree/Test.hs . I was in the middle of a program-wide change when I ran into this GHC panic; I was using the type errors to guide my fixes. The Test.hs is not type correct, but I don't see how the stuff I changed as anything to do with my use of type-level strings (!TypeLits). The code in the previous commit compiles. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9036> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9042: List indenting in case fails
by GHC 27 Apr '14

27 Apr '14

#9042: List indenting in case fails ------------------------------------+------------------------------------- Reporter: laar | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | 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: | ------------------------------------+------------------------------------- The following code fails to parse {{{ module Temp where t = case [1..2] of [ 1 , 2 ] -> True _ -> False }}} with {{{ Temp.hs:5:9: parse error (possibly incorrect indentation or mismatched brackets) }}} Which relates to the line `, 2`. Indenting both that line and the next one is needed to parse the module. This is contrary to what I suspected. As this vertical layout for lists is allowed as expression, I would also expect it to work for patterns. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9042> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7730: :info and polykinds
by GHC 27 Apr '14

27 Apr '14

#7730: :info and polykinds --------------------------------------------+------------------------------ Reporter: monoidal | Owner: archblob Type: bug | Status: new Priority: normal | Milestone: 7.8.3 Component: Compiler (Type checker) | Version: 7.6.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: #8776 --------------------------------------------+------------------------------ Comment (by archblob): We could solve (2) by just adding another field to {{{IfaceConDecl}}} in order to also keep the original bang info and not just the representation one. I'm still investigating (1) and trying to find the corect way to distinguish kinds from types using the information we have available. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7730#comment:27> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #917: -O introduces space leak
by GHC 27 Apr '14

27 Apr '14

#917: -O introduces space leak -------------------------------------+------------------------------------ Reporter: claus.reinke@… | Owner: Type: bug | Status: new Priority: lowest | Milestone: ⊥ Component: Compiler | Version: 6.5 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Changes (by pivo): * cc: pivo@… (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/917#comment:17> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9026: [CID43163, CID43172] Use correct variable in NULL-check
by GHC 27 Apr '14

27 Apr '14

#9026: [CID43163, CID43172] Use correct variable in NULL-check ------------------------------------+------------------------------------- Reporter: nicolast | Owner: simonmar Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 7.8.2 Keywords: coverity | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- I *think* the attached patch fixes the issue reported by Coverity as CID43163, which then fixes CID43172 as a side-effect as well. Please give this a close look. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9026> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9024: [CID43166] Memleak in initProfiling2
by GHC 27 Apr '14

27 Apr '14

#9024: [CID43166] Memleak in initProfiling2 ------------------------------------+------------------------------------- Reporter: nicolast | Owner: simonmar Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 7.8.2 Keywords: coverity | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: Other Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- The Coverity scan discovered a (small) memory leak in the error-path of initProfiling2. The attached patch should fix this. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9024> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9027: [CID43165] Potential out-of-bounds memory access in hp2ps
by GHC 27 Apr '14

27 Apr '14

#9027: [CID43165] Potential out-of-bounds memory access in hp2ps ------------------------------------+------------------------------------- Reporter: nicolast | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: None | Version: 7.8.2 Keywords: coverity, hp2ps | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Coverity discovered a potential out-of-bound memory access scenario in hp2ps. I think the attached patch is a possible solution. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9027> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9028: [CID43167] Fix memleak in hp2ps
by GHC 27 Apr '14

27 Apr '14

#9028: [CID43167] Fix memleak in hp2ps ------------------------------------+------------------------------------- Reporter: nicolast | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: None | Version: 7.8.2 Keywords: coverity, hp2ps | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Coverity found a memleak in hp2ps, an allocated buffer not being freed. Attached patch adds the free call. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9028> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9029: [CID43142] Check return value of sigaction
by GHC 27 Apr '14

27 Apr '14

#9029: [CID43142] Check return value of sigaction ------------------------------------+------------------------------------- Reporter: nicolast | Owner: simonmar Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 7.8.2 Keywords: coverity | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Coverity pointed at a location where the return value of sigaction isn't checked, unlike other occurrences of the function call. This patch adds the call, in line with other code. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9029> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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