#1552: GHCi thinks large list literals impossible?
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Reporter: SamB | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: GHCi | Version: 6.6
Severity: normal | Keywords:
Difficulty: Unknown | Os: Unknown
Testcase: | Architecture: Unknown
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{{{
Prelude> :set -fth
Prelude> $(let s = replicate 26227 'x' in [| s |])
Loading package template-haskell ... linking ... done.
ghc-6.6: panic! (the 'impossible' happened)
(GHC version 6.6 for i386-unknown-linux):
mkProtoBCO: stack use won't fit in 16 bits 131145
}}}
Note: I ran into this with a far more interestinng string, which I
actually used TH to generate, but the code was a lot longer. I think this
happens partly because {{{String}}}s are lifted as {{{ListE}}s of {{{(LitE
. CharL)}}}s, rather than as {LitE . StrinL}s, but even if you changed
that I could still get the same thing to happen by replacing {{{'x'}}}
with {{{(1::Int)}}}, so obviously that isn't the whole problem. (Why in
the world does the code for long list literals need an enormous stack
anyway?)
On a side note, this also crashes -ddump-ds, though that's probably
reasonable...
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1552>
GHC <http://www.haskell.org/ghc/>
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