[GHC] #15932: DeriveFunctor and GeneralizedNewtypeDeriving instances never reporting as covered

[GHC]

#15932: DeriveFunctor and GeneralizedNewtypeDeriving instances never reporting as
covered
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           Reporter:  davean         |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  low            |         Milestone:  8.6.3
          Component:  Code Coverage  |           Version:  8.6.2
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  Other
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 When testing coverage of test cases, HPC does not report some instances as
 receiving coverage even though it seems they are. Particularly, when one
 hand derives the functions they show full coverage. The specific instances
 in question appear to be ones derived via DeriveFunctor and
 GeneralizedNewtypeDeriving. Problems have been observed with at least
 Functor, Applicative, and Monad.

 A minimal example is attached, and available as a cabal project at
 https://code.xkrd.net/davean/minimal-coverage-test. To reproduce, run
 "cabal v2-test --enable-coverage" and view the resulting coverage HTML
 files.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15932>
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