[GHC] #10103: Outdated comment (or bug?) in TyCon.hs

[GHC]

#10103: Outdated comment (or bug?) in TyCon.hs
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              Reporter:  thomie      |             Owner:
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:  7.12.1
             Component:  Compiler    |           Version:  7.8.4
              Keywords:              |  Operating System:  Unknown/Multiple
          Architecture:              |   Type of failure:  None/Unknown
  Unknown/Multiple                   |        Blocked By:
             Test Case:              |   Related Tickets:
              Blocking:              |
Differential Revisions:              |
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 The docstring for `coreExpandTyCon_maybe` says it should do something
 different than `tcExpandTyCon_maybe`, but it doesn't:

 {{{#!haskell
 -- ^ Used to create the view the /typechecker/ has on 'TyCon's.
 -- We expand (closed) synonyms only, cf. 'coreExpandTyCon_maybe'
 tcExpandTyCon_maybe = ...

 -- ^ Used to create the view /Core/ has on 'TyCon's. We expand
 -- not only closed synonyms like 'tcExpandTyCon_maybe',
 -- but also non-recursive @newtype at s
 coreExpandTyCon_maybe tycon tys = tcExpandTyCon_maybe tycon tys
 }}}

 If the code is correct, and the comment is just outdated, than Note
 [Newtype eta] and the docstring for `Type.coreView` should be updated as
 well.

 The last big change to `coreExpandTyCon_maybe` was made in commit
 fdf8656855d26105ff36bdd24d41827b05037b91.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10103>
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