[GHC] #14391: Make the simplifier independent of the typechecker

[GHC]

#14391: Make the simplifier independent of the typechecker
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        Reporter:  nomeata           |                Owner:  ulysses4ever
            Type:  task              |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.3
      Resolution:                    |             Keywords:  newcomer
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D4503
       Wiki Page:                    |
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Comment (by ulysses4ever):

 Let's turn to `thNameToGhcName` now. We want to remove `initTcForLookup`
 from it, and for this we need to replace `lookupThName_maybe` with Tc-less
 version.

 The `lookupThName_maybe`, in turn, depends on `lookupGlobalOccRn_maybe`
 which seems to be very `Rn`-heavy inside. So I'm not sure how to proceed:
 should I try to rewrite `lookupGlobalOccRn_maybe` or leave it. In the
 latter case we need to find a way to run `RnM` in `thNameToGhcName`,
 which, I guess, not far from the dreaded `initTcForLookup`?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14391#comment:20>
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