#845: irrefutable pattern matching on unboxed tuple causes panic
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Reporter: Jason McCarty <[EMAIL PROTECTED]> | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 6.4.2
Severity: normal | Keywords:
Os: Linux | Difficulty: Unknown
Architecture: x86 |
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Compiling the following program with -fglasgow-exts
main = case (# (), () #) of ~(# _, _ #) -> return ()
causes GHC to fail with the message
ghc-6.4.2: panic! (the `impossible' happened, GHC version 6.4.2):
dsLExpr: tuple pattern:
return @ () GHC.Base.()
The equivalent (I think) expression
main = let (# _, _ #) = (# (), () #) in return ()
compiles without complaint.
This is GHC version 6.4.2 on i386 Debian with a 2.6.17.6 Linux kernel. I
didn't test with any other unboxed types.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/845>
GHC <http://www.haskell.org/ghc/>
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