[haddock] #94: Give a warning message instead of an error when encountering unexpected Haddock comments

[haddock]

#94: Give a warning message instead of an error when encountering unexpected
Haddock comments
------------------------+---------------------------------------------------
Reporter:  waern        |       Owner:     
    Type:  enhancement  |      Status:  new
Priority:  major        |   Milestone:  _|_
 Version:               |    Keywords:     
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 See this failure when processing XMonad:
 {{{
 XMonad/Layout.hs:55:19: parse error on input `!' haddock: Failed to check
 module: XMonad.Layout

 The relevant lines:

 data Tall a = Tall !Int -- ^ The default number of windows in the master
 pane (default: 1) !Rational -- ^ Default proportion of screen occupied by
 master pane (default: 1/2) !Rational; -- ^ Percent of screen to increment
 by when resizing panes (default: 3/100)
 }}}

 Since we don't support Haddock comments on individual arguments of
 constructors, this just fails with a parse error. Perhaps we should just
 give a warning in case like this, where a Haddock comment is encountered
 at an unexpected place.

 I think this is hard to implement, given the way things currently work.
 Haddock comments are just ordinary tokens that are fed to the parser, and
 we clearly don't want put them all over the grammar. If we should move to
 a design where Haddock comments are not in the grammar, but are collected
 elsewhere, implement this ticket would be a lot easier.

-- 
Ticket URL: <http://trac.haskell.org/haddock/ticket/94>
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