[GHC] #14252: ApplicativeDo: Add compiler message about irrefutable pattern matches and Monad constraints

[GHC]

#14252: ApplicativeDo: Add compiler message about irrefutable pattern matches and
Monad constraints
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        Reporter:  mutantmell        |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:  8.4.1
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:
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 mutantmell):

 I changed the wording of the ticket to be more clear with my original
 intent: add a message when a user provided signature clashes with what
 ApplicativeDo allows, similar to when enabling an extension would allow
 code to compile.  This should be less obtrusive for users who don't want
 to be bugged, while providing a message that would help people make their
 code compile.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14252#comment:5>
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