[GHC] #10547: feature request: expanding type synonyms in error messages

[GHC]

#10547: feature request: expanding type synonyms in error messages
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              Reporter:  osa1        |             Owner:  osa1
                  Type:  feature     |            Status:  new
  request                            |         Milestone:  7.12.1
              Priority:  low         |           Version:
             Component:  Compiler    |  Operating System:  Unknown/Multiple
  (Type checker)                     |   Type of failure:  None/Unknown
              Keywords:              |        Blocked By:
          Architecture:              |   Related Tickets:
  Unknown/Multiple                   |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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 Type errors sometimes becoming confusing because of synonyms, for example,
 expected type and found type sometimes use different synonyms or sometimes
 only one of them use a synonym etc.

 We discussed this in the mailing list: https://mail.haskell.org/pipermail
 /ghc-devs/2015-June/009247.html
 And also moved it to the Wiki to collect examples:
 https://wiki.haskell.org/Expanding_type_synonyms_in_error_messages_proposal

 I'm currently working on a patch, I made some progress and I'll hopefully
 submit something for reviews in a couple of days.

 This ticket is for further discussions and keep track of the progress.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10547>
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