[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:  (none)
            Type:  task              |               Status:  new
        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):
       Wiki Page:                    |
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Comment (by ulysses4ever):

 As it seems to stale for a while, I'd like to give it a try.

 IIUC, the strategy laid by Simon suggests developing a `Tc`-less version
 of `lookupGlobal`. For this we need to identify ties to `Tc` inside it and
 then try to cut those.

 First tie (also spelled by Simon above) is “`tcg_type_env`, which was
 initialised by `initTcForLookup`”. I looked at `initTcForLookup` and its
 dependencies, and it seems to me that `tcg_type_env`is initialized with
 `emptyNameEnv` there. A question: does that mean that corresponding part
 of the `tcLookupGlobal` which queries `tcg_type_env` is not needed at all
 and can be omitted in the `Tc`-less version of `lookupGlobal`?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14391#comment:7>
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