[GHC] #15617: Unboxed tuples/sum error message on `a = show 5` in expression evaluation and interactive modes

[GHC]

#15617: Unboxed tuples/sum error message on `a = show 5` in expression evaluation
and interactive modes
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        Reporter:  ChaiTRex          |                Owner:
                                     |  JulianLeviston
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.6.1-beta1
      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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Changes (by osa1):

 * cc: RolandSenn (added)


Comment:

 I think you're right. This is another example of problems caused by not
 having the information of whether we're in interpreter or not in the
 compiler (we only have information derived from the flags but that
 information can't tell reliably whether we're in interpreter, as in this
 ticket). @RolandSenn has a good summary of the problem in Phab:D5122 which
 also links to a few other issues caused by this problem. Perhaps we should
 do the refactoring to add a field to DynFlags about whether we're in
 interepreter.

 If we do this then maybe we should revisit some of the fixed tickets and
 fix them "properly" by using the new field.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15617#comment:9>
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