Re: [GHC] #11184: panic tcMonoExpr _ with bad indentation in TH code

9 Dec 2015

      #11184: panic tcMonoExpr _ with bad indentation in TH code
-------------------------------------+-------------------------------------
        Reporter:  TeroLaitinen      |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Runtime crash     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by phadej):

 This happens because some "grammar" checks happen after the parsing phase:

 This fails with parse error:
 {{{
 foo = \x -> case x of
                "foo" -> "bar"
                   _ -> x

 {-
 bar.hs:32:21: parse error on input ‘->’
 -}
 }}}

 But this, which is triggered in TH slice, is something different:
 {{{
 foo = (\x -> case x of
                "foo" -> "bar"
                   _ -> x)

 {-
 bar.hs:20:8:
     Pattern syntax in expression context:
         \ x -> case x of { "foo" -> "bar" (...) } -> x
 -}
 }}}

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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11184#comment:1
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