Re: [GHC] #3822: guards in arrow notation (Arrows extension) case statement cause compiler panic
#3822: guards in arrow notation (Arrows extension) case statement cause compiler panic -+-- Reporter: StephenBlackheath | Owner: ross Type: bug | Status: closed Priority: high| Milestone: 6.14.1 Component: Compiler|Version: 6.12.1 Resolution: fixed | Keywords: arrows guards case panic Difficulty: | Os: Unknown/Multiple Testcase: T3822 | Architecture: Unknown/Multiple Failure: Compile-time crash | -+-- Changes (by igloo): * status: merge = closed * testcase: patternGuard.hs = T3822 * resolution: = fixed * milestone: 6.12.3 = 6.14.1 Comment: Thanks! Test added. Not merging, as we won't be making another 6.12 release. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/3822#comment:12 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #3822: guards in arrow notation (Arrows extension) case statement cause compiler panic
#3822: guards in arrow notation (Arrows extension) case statement cause compiler
panic
-+--
Reporter: StephenBlackheath |Owner: ross
Type: bug | Status: merge
Priority: high |Milestone: 6.12.3
Component: Compiler | Version: 6.12.1
Keywords: arrows guards case panic | Difficulty:
Os: Unknown/Multiple | Testcase: patternGuard.hs
Architecture: Unknown/Multiple | Failure: Compile-time crash
-+--
Changes (by ross):
* status: new = merge
Comment:
I believe this is fixed by
{{{
Tue Jun 15 15:51:10 PDT 2010 Ross Paterson ross at soi.city.ac.uk
* fix #3822: desugaring case command in arrow notation
}}}
--
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/3822#comment:11
GHC http://www.haskell.org/ghc/
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Re: [GHC] #3822: guards in arrow notation (Arrows extension) case statement cause compiler panic
#3822: guards in arrow notation (Arrows extension) case statement cause compiler panic -+-- Reporter: StephenBlackheath |Owner: ross Type: bug | Status: new Priority: high |Milestone: 6.12.3 Component: Compiler | Version: 6.12.1 Keywords: arrows guards case panic | Difficulty: Os: Unknown/Multiple | Testcase: patternGuard.hs Architecture: Unknown/Multiple | Failure: Compile-time crash -+-- Comment(by simonmar): Ross: sorry for the delay in getting back to you. Which bit of code is responsible for recognising variables as being used? Is it arrows- specific, or somewhere else? Can you help us fix it? (Cheers, Simon Simon) -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/3822#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #3822: guards in arrow notation (Arrows extension) case statement cause compiler panic
#3822: guards in arrow notation (Arrows extension) case statement cause compiler
panic
-+--
Reporter: StephenBlackheath |Owner: ross
Type: bug | Status: new
Priority: normal|Milestone: 6.12.2
Component: Compiler | Version: 6.12.1
Keywords: arrows guards case panic | Difficulty:
Os: Unknown/Multiple | Testcase: patternGuard.hs
Architecture: Unknown/Multiple | Failure: Compile-time crash
-+--
Comment(by simonpj):
Slightly smaller test case
{{{
{-# LANGUAGE Arrows #-}
module T3822 where
import Control.Arrow
test :: Int - Int
test = proc x - do
let neg = x 0
case x of
x | neg - returnA - 0 -- GHC panics
_ - returnA - 10
}}}
Ross: can you see what is wrong? Core Lint gives the error below after
desugaring:
{{{
*** Core Lint errors : in result of Desugar ***
no location info:
[in body of letrec with binders fail_dnE :: GHC.Prim.State#
GHC.Prim.RealWorld
- Data.Either.Either ()
()]
neg_acJ is out of scope
*** Offending Program ***
Rec {
T3822.test :: GHC.Types.Int - GHC.Types.Int
[LclIdX]
T3822.test =
_aiG
@ GHC.Types.Int
@ GHC.Types.Int
@ GHC.Types.Int
(arr_aix
@ GHC.Types.Int
@ GHC.Types.Int
(\ (x_acI :: GHC.Types.Int) - x_acI))
(_aiG
@ GHC.Types.Int
@ GHC.Types.Int
@ GHC.Types.Int
(arr_aix
@ GHC.Types.Int
@ GHC.Types.Int
(\ (ds_dnJ :: GHC.Types.Int) -
let {
x_acI :: GHC.Types.Int
[LclId]
x_acI = ds_dnJ } in
letrec {
neg_acJ :: GHC.Bool.Bool
[LclId]
neg_acJ = _ai2 x_acI (GHC.Types.I# 0);
neg_ai3 :: GHC.Bool.Bool
[LclId]
neg_ai3 = neg_acJ; } in
x_acI))
(_aiG
@ GHC.Types.Int
@ (Data.Either.Either () ())
@ GHC.Types.Int
(arr_aix
@ GHC.Types.Int
@ (Data.Either.Either () ())
(\ (ds_dnH :: GHC.Types.Int) -
let {
x_acI :: GHC.Types.Int
[LclId]
x_acI = ds_dnH } in
let {
x_ahI :: GHC.Types.Int
[LclId]
x_ahI = x_acI } in
let {
fail_dnE
:: GHC.Prim.State# GHC.Prim.RealWorld -
Data.Either.Either () ()
[LclId]
fail_dnE =
\ (ds_dnF :: GHC.Prim.State# GHC.Prim.RealWorld) -
Data.Either.Right @ () @ () GHC.Unit.() } in
case neg_acJ of wild_B1 {
GHC.Bool.False - fail_dnE GHC.Prim.realWorld#;
GHC.Bool.True - Data.Either.Left @ () @ () GHC.Unit.()
}))
(|||_aiK
@ ()
@ GHC.Types.Int
@ ()
(_aiG
@ ()
@ GHC.Types.Int
@ GHC.Types.Int
(arr_aix
@ ()
@ GHC.Types.Int
(\ (ds_dnB :: ()) -
case ds_dnB of ds_dnB { () - GHC.Types.I# 0 }))
returnA_aig)
(_aiG
@ ()
@ GHC.Types.Int
@ GHC.Types.Int
(arr_aix
@ ()
@ GHC.Types.Int
(\ (ds_dnD :: ()) -
case ds_dnD of ds_dnD { () - GHC.Types.I# 10 }))
returnA_ain
|||_aiK
:: forall b_ami d_amj c_amk.
(b_ami - d_amj)
- (c_amk - d_amj)
- Data.Either.Either b_ami c_amk
- d_amj
[LclId]
|||_aiK = Control.Arrow.||| @ (-) $dArrowChoice_anx
$dArrow_anw :: Control.Arrow.Arrow (-)
[LclId]
$dArrow_anw = $dArrow_anq
first_aiH
:: forall b_aiN c_aiO d_aiP.
(b_aiN - c_aiO) - (b_aiN, d_aiP) - (c_aiO, d_aiP)
[LclId]
first_aiH = Control.Arrow.first @ (-) $dArrow_anw
$dArrow_anv :: Control.Arrow.Arrow (-)
[LclId]
$dArrow_anv = $dArrow_anq
_aiG
:: forall a_aiD b_aiE c_aiF.
(a_aiD - b_aiE) - (b_aiE - c_aiF) - a_aiD - c_aiF
[LclId]
_aiG = GHC.Desugar. @ (-) $dArrow_anv
$dArrow_anu :: Control.Arrow.Arrow (-)
[LclId]
$dArrow_anu = $dArrow_anq
arr_aix :: forall b_aiL c_aiM. (b_aiL - c_aiM) - b_aiL - c_aiM
[LclId]
arr_aix = Control.Arrow.arr @ (-)
Re: [GHC] #3822: guards in arrow notation (Arrows extension) case statement cause compiler panic
#3822: guards in arrow notation (Arrows extension) case statement cause compiler panic -+-- Reporter: StephenBlackheath |Owner: ross Type: bug | Status: new Priority: normal|Milestone: 6.12.2 Component: Compiler | Version: 6.12.1 Keywords: arrows guards case panic | Difficulty: Os: Unknown/Multiple | Testcase: patternGuard.hs Architecture: Unknown/Multiple | Failure: Compile-time crash -+-- Comment(by ross): Replying to [comment:7 simonpj]: Ross: can you see what is wrong? Core Lint gives the error below after desugaring: Yes, variables occurring only in guards are not being recognized as being used, so they're discarded from the pipeline before reaching the case. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/3822#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #3822: guards in arrow notation (Arrows extension) case statement cause compiler panic
#3822: guards in arrow notation (Arrows extension) case statement cause compiler
panic
-+--
Reporter: StephenBlackheath |Owner: ross
Type: bug | Status: new
Priority: normal|Milestone:
Component: Compiler | Version: 6.12.1
Keywords: arrows guards case panic | Difficulty:
Os: Unknown/Multiple | Testcase: patternGuard.hs
Architecture: Unknown/Multiple | Failure: Compile-time crash
-+--
Description changed by igloo:
Old description:
The attached test case causes this panic message:
-
ghc: panic! (the 'impossible' happened)
(GHC version 6.12.1 for x86_64-unknown-linux):
initC: srt_lbl
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
-
The offending line is the one with '| neg'. It doesn't panic if you use
the commented out line below it instead.
This kind of case statement is specific to arrow notation (provided by
the Arrows extension) - the compiler uses ArrowChoice to implement it.
New description:
The attached test case causes this panic message:
{{{
ghc: panic! (the 'impossible' happened)
(GHC version 6.12.1 for x86_64-unknown-linux):
initC: srt_lbl
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
}}}
The offending line is the one with '| neg'. It doesn't panic if you use
the commented out line below it instead.
This kind of case statement is specific to arrow notation (provided by the
Arrows extension) - the compiler uses ArrowChoice to implement it.
--
--
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/3822#comment:5
GHC http://www.haskell.org/ghc/
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Re: [GHC] #3822: guards in arrow notation (Arrows extension) case statement cause compiler panic
#3822: guards in arrow notation (Arrows extension) case statement cause compiler panic -+-- Reporter: StephenBlackheath |Owner: ross Type: bug | Status: new Priority: normal|Milestone: 6.12.2 Component: Compiler | Version: 6.12.1 Keywords: arrows guards case panic | Difficulty: Os: Unknown/Multiple | Testcase: patternGuard.hs Architecture: Unknown/Multiple | Failure: Compile-time crash -+-- Changes (by igloo): * milestone: = 6.12.2 -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/3822#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #3822: guards in arrow notation (Arrows extension) case statement cause compiler panic (was: pattern guards in arrow notation (Arrows extension) case statement cause compiler panic)
#3822: guards in arrow notation (Arrows extension) case statement cause compiler panic --+- Reporter: StephenBlackheath | Owner: ross Type: bug| Status: new Priority: normal | Component: Compiler Version: 6.12.1 |Keywords: arrows guards case panic Os: Unknown/Multiple |Testcase: patternGuard.hs Architecture: Unknown/Multiple | Failure: Compile-time crash --+- Changes (by ross): * keywords: arrows pattern guards case panic = arrows guards case panic * os: Linux = Unknown/Multiple * architecture: x86_64 (amd64) = Unknown/Multiple -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/3822#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
