[GHC] #14118: Strangeness regarding STG alternative types and linter

[GHC]

#14118: Strangeness regarding STG alternative types and linter
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        Reporter:  bgamari           |                Owner:  (none)
            Type:  bug               |               Status:  patch
        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):  Phab:D3889
       Wiki Page:                    |
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Changes (by bgamari):

 * differential:  Phab:D3858 => Phab:D3889


Comment:

 Here is a patch fixing the linter to only check the invariant post-
 unarisation.

 > Incidentally, this should also be true of lambda binders, whether used
 or not; before Unarise they can be unboxed tuples, but not after.

 The StgLinter considers any `StgLam` expression to be an error, so this
 case should already be covered.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14118#comment:7>
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