Re: [GHC] #1080: Arrows desguaring does not take account of bindings in patterns
#1080: Arrows desguaring does not take account of bindings in patterns -+-- Reporter: simonpj |Owner: ross Type: bug | Status: closed Priority: normal|Milestone: 6.8 Component: Compiler | Version: 6.7 Severity: normal| Resolution: fixed Keywords:| Difficulty: Unknown Os: Unknown | Testcase: arrowcase1 Architecture: Unknown | -+-- Changes (by ross): * resolution: = fixed * status: new = closed -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1080 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] #1080: Arrows desguaring does not take account of bindings in patterns
#1080: Arrows desguaring does not take account of bindings in patterns -+-- Reporter: simonpj |Owner: ross Type: bug | Status: new Priority: normal|Milestone: 6.8 Component: Compiler | Version: 6.7 Severity: normal| Resolution: Keywords:| Difficulty: Unknown Os: Unknown | Testcase: arrowcase1 Architecture: Unknown | -+-- Comment (by simonpj): Ross says he'll get to this in mid to late June 2007. Simon -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1080 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] #1080: Arrows desguaring does not take account of bindings in patterns
#1080: Arrows desguaring does not take account of bindings in patterns +--- Reporter: simonpj | Owner: ross Type: bug | Status: new Priority: normal | Milestone: 6.6.1 Component: Compiler|Version: 6.6 Severity: normal | Resolution: Keywords: | Difficulty: Unknown Testcase: arrowcase1 | Architecture: Unknown Os: Unknown | +--- Changes (by simonpj): * owner: Ross Paterson = ross Comment: See also #1124, which is a dup of this one. I've added its code as an attachment, `Ar.hs`. Simon -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1080 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] #1080: Arrows desguaring does not take account of bindings in patterns
#1080: Arrows desguaring does not take account of bindings in patterns +--- Reporter: simonpj | Owner: Ross Paterson Type: bug | Status: new Priority: normal | Milestone: 6.6.1 Component: Compiler|Version: 6.6 Severity: normal | Resolution: Keywords: | Difficulty: Unknown Testcase: arrowcase1 | Architecture: Unknown Os: Unknown | +--- Changes (by igloo): * milestone: = 6.6.1 -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1080 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
[GHC] #1080: Arrows desguaring does not take account of bindings in patterns
#1080: Arrows desguaring does not take account of bindings in patterns
-+--
Reporter: simonpj | Owner: Ross Paterson
Type: bug | Status: new
Priority: normal| Milestone:
Component: Compiler | Version: 6.6
Severity: normal|Keywords:
Difficulty: Unknown |Testcase:
Architecture: Unknown | Os: Unknown
-+--
The test arrows/should_compile/arrowcase1 is failing Lint. The bug is in
the desugarer.
Here’s a smaller test case:
{{{
h :: ArrowChoice a = Int - a (Int,Int) Int
h x = proc (y,z) - case compare x y of
GT - returnA - z+x
}}}
The type checker turns the case into
{{{
case compare x y of
GT { p77 = plusInt } - returnA - p77 z x
}}}
Here p77 is a local binding for the (+) operation. In general, patterns
can contain bindings (used to discharge constraints that are bound by the
pattern). In this case the binding isn’t strictly necessary, but in
general it is – consider existentials. It’s equivalent to adding a
‘let’ around the RHS, but since the patters are perhaps nested, and
one pattern might use a constraint that is bound by another, the pattern
is the right place to attach the binding.
This has come up because GHC is binding things a little earlier than
before, but an existential would have exposed it before.
The trouble is that the suspicious-looking replaceLeaves code in DsArrows
(line 528 or so) doesn’t know about these bindings.
I don’t understand DsArrows at all. Indeed the whole Arrows code feels
smelly to me. Maybe we tried to share too much code?
I'm hoping Ross will look at this.
--
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1080
GHC http://www.haskell.org/ghc/
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Re: [GHC] #1080: Arrows desguaring does not take account of bindings in patterns
#1080: Arrows desguaring does not take account of bindings in patterns +--- Reporter: simonpj | Owner: Ross Paterson Type: bug | Status: new Priority: normal | Milestone: Component: Compiler|Version: 6.6 Severity: normal | Resolution: Keywords: | Difficulty: Unknown Testcase: arrowcase1 | Architecture: Unknown Os: Unknown | +--- Changes (by simonpj): * testcase: = arrowcase1 -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1080 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
