#1513: odd panic with [()] >>> ()
-------------------------------+--------------------------------------------
Reporter: [EMAIL PROTECTED] | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 6.6
Severity: normal | Keywords: panic
Difficulty: Unknown | Os: Linux
Testcase: | Architecture: x86
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While messing around with arrows in GHCi, I was surprised to see the
following (ill-typed) code cause a panic:
{{{
___ ___ _
/ _ \ /\ /\/ __(_)
/ /_\// /_/ / / | | GHC Interactive, version 6.6, for Haskell 98.
/ /_\\/ __ / /___| | http://www.haskell.org/ghc/
\____/\/ /_/\____/|_| Type :? for help.
Loading package base ... linking ... done.
Prelude> :m Control.Arrow
Prelude Control.Arrow> [1, 2] >>> pure (+1)
ghc-6.6: panic! (the 'impossible' happened)
(GHC version 6.6 for i386-unknown-linux):
nameModule it{v aIS}
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
}}}
Further experimentation revealed that
{{{
[] >>> ()
}}}
is a type-error as expected, whereas
{{{
[()] >>> ()
}}}
causes a panic.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1513>
GHC <http://www.haskell.org/ghc/>
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