[GHC] #10908: -fwarn-missing-exported-sigs doesn't respect qualified names

[GHC]

#10908: -fwarn-missing-exported-sigs doesn't respect qualified names
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              Reporter:  goldfire    |             Owner:
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Compiler    |           Version:  7.10.2
              Keywords:              |  Operating System:  Unknown/Multiple
          Architecture:              |   Type of failure:  Incorrect
  Unknown/Multiple                   |  warning at compile-time
             Test Case:              |        Blocked By:
              Blocking:              |   Related Tickets:
Differential Revisions:              |
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 Trying to help @mpickering with Phab:D1258, I looked at the code in
 `tcRnSrcDecls` and was surprised to see that exports are renamed after
 this function is complete. This didn't make any sense to me. And, indeed,
 it's wrong, witness by this example:

 {{{
 {-# OPTIONS_GHC -fwarn-missing-exported-sigs #-}

 module Bug (Data.List.intercalate, x) where

 import qualified Data.List

 intercalate = True

 x :: Bool
 x = intercalate
 }}}

 This produces

 {{{
 Bug.hs:7:1: Warning:
     Top-level binding with no type signature: intercalate :: Bool
 }}}

 This warning should not be emitted.

 I'm not all that concerned about this scenario biting in the wild, but it
 suggests that refactoring this code is a good thing, and not something
 Phab:D1258 should take pains to avoid.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10908>
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