[GHC] #11179: Allow plugins to access "dead code"

[GHC]

#11179: Allow plugins to access "dead code"
-------------------------------------+-------------------------------------
        Reporter:  lerkok            |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.2
      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:                    |
-------------------------------------+-------------------------------------
Changes (by nomeata):

 * related:  #10823 =>


Comment:

 I have his this problem as well now. I don’t like any solution that
 requires unwieldy interaction from the user. That leaves
  * not removing dead code in the desugarer or
  * adding a hook to the plugins interface to interact with the code before
 desugaring (and maybe mark bindings as “please keep”)

 While the second one would surely be useful for many other things, I
 wonder why we not simply do the first one. We remove dead code later
 anyways (do we?), and the extra cost of desugaring dead code seems to be
 neglectible, as there usually is no dead code. (And if there is, then most
 likely for a good reason – e.g. to be picked up by plugins).

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11179#comment:7>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler