ghc: panic! (the 'impossible' happened)
simonpj at microsoft.com
Sun Oct 28 19:51:25 CET 2012
Thanks. Certainly a bug. I've created a ticket http://hackage.haskell.org/trac/ghc/ticket/7372.
Turns out that it's fixed in HEAD already, and I *think* the fix is in http://hackage.haskell.org/trac/ghc/ticket/7312, which should get into 7.6.2.
| -----Original Message-----
| From: glasgow-haskell-users-bounces at haskell.org [mailto:glasgow-haskell-users-
| bounces at haskell.org] On Behalf Of Sjoerd Visscher
| Sent: 28 October 2012 11:46
| To: José Romildo Malaquias
| Cc: glasgow-haskell-users at haskell.org
| Subject: Re: ghc: panic! (the 'impossible' happened)
| You can avoid the error by replacing
| eval :: Exp -> (->) Memory Integer
| eval :: Exp -> Memory -> Integer
| which should be the same, but apparently isn't internally in GHC. This is definitely
| a bug.
| On Oct 28, 2012, at 4:55 AM, José Romildo Malaquias <j.romildo at gmail.com>
| > Hello.
| > Today I wrote a small program to experiment with the Applicative
| > class. The program is supposed to use an "applicative reader", similar
| > to a "monad reader", to evaluate arithmetic expressions.
| > But when compiling the program with ghc-7.6.1, I get the following message:
| > $ ghc --make applicative-eval
| > [1 of 1] Compiling Main ( applicative-eval.hs, applicative-eval.o )
| > ghc: panic! (the 'impossible' happened)
| > (GHC version 7.6.1 for x86_64-unknown-linux):
| > expectJust cpeBody:collect_args
| > Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
| > If the line
| > eval (Let s a b) = \m -> eval b ((s,eval a m):m)
| > is commented out, the program compiles without problems.
| > Is this a known issue with the compiler?
| > The source code is attached.
| > Romildo
| > <applicative-
| > Glasgow-haskell-users mailing list
| > Glasgow-haskell-users at haskell.org
| > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
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