[GHC] #14761: Incorrect diagnostic for UNPACK/missing strictness

[GHC]

#14761: Incorrect diagnostic for UNPACK/missing strictness
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        Reporter:  dminuoso          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect         |  Unknown/Multiple
  error/warning at compile-time      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #7210             |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by dminuoso):

 The problem only seems to trigger when there's a type constructor.
 {{{#!hs
 data A = A { a :: {-# UNPACK #-} Maybe Int}     -- Wrong diagnostic
 data A = A { a :: {-# UNPACK #-} (,) Int Int }  -- Wrong diagnostic
 }}}

 But not with the special type syntax or unary types
 {{{#!hs
 data A = A { a :: {-# UNPACK #-} (Int, Int) } -- Works
 data A = A { a :: {-# UNPACK #-} Int }        -- Works
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14761#comment:1>
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