[GHC] #13187: Strange debug output printed: isPredTy Const Int (, ) Bool Char

[GHC]

#13187: Strange debug output printed: isPredTy Const Int (,) Bool Char
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        Reporter:  RyanGlScott       |                Owner:
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler (Type    |              Version:  8.1
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Poor/confusing    |  Unknown/Multiple
  error message                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D3033
       Wiki Page:                    |
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Comment (by Ryan Scott <ryan.gl.scott@…>):

 In [changeset:"bc42e2b03a87e3f6c0d24584382f281c6580801b/ghc" bc42e2b/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="bc42e2b03a87e3f6c0d24584382f281c6580801b"
 Convert pprTrace in isPredTy to a WARN

 Summary:
 There was a `pprTrace` in `isPredTy` that could fire under certain
 scenarios, causing normal GHC users to see debugging output. This turns it
 into
 a less chatty `WARN`, and expounds on the comment below it to add the
 scenario
 in #13187 which triggered the `pprTrace`.

 Reviewers: goldfire, austin, bgamari

 Reviewed By: goldfire, bgamari

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D3033

 GHC Trac Issues: #13187
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13187#comment:4>
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