[GHC] #16305: When should -Wmissed-specializations fire?

[GHC]

#16305: When should -Wmissed-specializations fire?
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        Reporter:  crockeea          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.7
      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):
       Wiki Page:                    |
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Comment (by crockeea):

 I should point out that the fact that `-Wmissed-specs` doesn't create a
 warning in the example above seems to (according to the code) be due to
 `showsPrec` not having any type of inline pragma. The following evaluates
 to `False` on `f=showsPrec`:

 `has_inline_prag f = isAnyInlinePragma (idInlinePragma f)`

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16305#comment:1>
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