Re: [GHC] #14371: ghc: panic! when reloading file with code

18 Oct 2017

      #14371: ghc: panic! when reloading file with code
-------------------------------------+-------------------------------------
        Reporter:  xvrbka1           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Description changed by xvrbka1:

Old description:
...
Hello,
\\
**
This code:**
{{{
countSame :: (Ord a) => (a -> Bool) [a] -> Int
countSame _ [] = 0;
countSame p (x:s) = (if p x then 1 else 0) + (countSame p s)
}}}
\\
**gives me an error:**\\
''ghc: panic! (the 'impossible' happened)
  (GHC version 8.2.1 for x86_64-unknown-linux):
        repSplitAppTys
  a_a6Xb[sk:1]
  Bool
  []
  Call stack:
      CallStack (from HasCallStack):
        prettyCurrentCallStack, called at
compiler/utils/Outputable.hs:1133:58 in ghc:Outputable
        callStackDoc, called at compiler/utils/Outputable.hs:1137:37 in
ghc:Outputable
        pprPanic, called at compiler/types/Type.hs:808:9 in ghc:Type''
\\
- All works when header is gone.
- I put this code in separate file and error still occurs so it should
not have any dependencies.

...
I hope I found u a bug :)
\\
Have a nice day
New description:

 Hello,

 \\
 **
 This code:**
 {{{
 countSame :: (Ord a) => (a -> Bool) [a] -> Int
 countSame _ [] = 0;
 countSame p (x:s) = (if p x then 1 else 0) + (countSame p s)
 }}}
 \\
 (There is a mistake in heared countSame :: (Ord a) => (a -> Bool) **->**
 [a] -> Int)
 \\

 **gives me an error:**\\

 ''ghc: panic! (the 'impossible' happened)
   (GHC version 8.2.1 for x86_64-unknown-linux):
         repSplitAppTys
   a_a6Xb[sk:1]
   Bool
   []
   Call stack:
       CallStack (from HasCallStack):
         prettyCurrentCallStack, called at
 compiler/utils/Outputable.hs:1133:58 in ghc:Outputable
         callStackDoc, called at compiler/utils/Outputable.hs:1137:37 in
 ghc:Outputable
         pprPanic, called at compiler/types/Type.hs:808:9 in ghc:Type''
 \\

 - On some machines correctly recognized as broken header
 - I put this code in separate file and error still occurs so it should not
 have any dependencies.

 I hope I found u a bug :)
 \\
 Have a nice day

--

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14371#comment:5
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