[GHC] #14608: Different GHCi error messages for similar scenarios

[GHC]

#14608: Different GHCi error messages for similar scenarios
-------------------------------------+-------------------------------------
        Reporter:  mb64              |                Owner:  (none)
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  GHCi              |              Version:  8.2.2
      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):  Phab:D4276
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"ecff651fc2f6d9833131e3e7fbc9a37b5b2f84ee/ghc"
 ecff651f/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="ecff651fc2f6d9833131e3e7fbc9a37b5b2f84ee"
 Fix #14608 by restoring an unboxed tuple check

 Commit 714bebff44076061d0a719c4eda2cfd213b7ac3d removed
 a check in the bytecode compiler that caught illegal uses of unboxed
 tuples (and now sums) in case alternatives, which causes the program
 in #14608 to panic. This restores the check (using modern,
 levity-polymorphic vocabulary).

 Test Plan: make test TEST=T14608

 Reviewers: hvr, bgamari, dfeuer, simonpj

 Reviewed By: dfeuer, simonpj

 Subscribers: simonpj, rwbarton, thomie, carter

 GHC Trac Issues: #14608

 Differential Revision: https://phabricator.haskell.org/D4276
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14608#comment:4>
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