[GHC] #12655: Bizarre parser problem: "Illegal bang-pattern" (something to do with CPP?)

[GHC]

#12655: Bizarre parser problem: "Illegal bang-pattern" (something to do with CPP?)
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        Reporter:  edsko             |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.4.2
      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:                    |
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Comment (by ezyang):

 Well, you can certainly jiggle around the preprocessor output until the
 lexer accepts it correctly, but the particular output depends a lot on
 system configuration so someone else might run into the issue. hvr has
 suggested that if you increase the default buffer size much larger, you're
 unlikely to run into the problem, but that requires a recompile of GHC.
 Another possibility is to put all the LANGUAGE flags in a single pragma so
 there is only one `{-` token to lex.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12655#comment:4>
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