[GHC] #11303: Pattern matching against sets of strings sharing a prefix blows up pattern checker

[GHC]

#11303: Pattern matching against sets of strings sharing a prefix blows up pattern
checker
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        Reporter:  bgamari           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.11
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:  T11303
      Blocked By:                    |             Blocking:
 Related Tickets:  #11302            |  Differential Rev(s):  Phab:D1716,
       Wiki Page:                    |  Phab:D1719
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Comment (by gkaracha):

 Replying to [comment:12 RyanGlScott]:
 > Another reason it's probably #11276 instead is because the same
 workaround can be applied to `text-icu`:
 > {...}
 > Adding a type signature makes the rest of `text-icu` compile.

 Ah, great! So `flag'` is the source of the problem. Then yes, they are
 definitely
 connected, probably something goes wrong with the types I assign to the
 initial
 uncovered set (I get it from the signature/inferred type). Thanks!

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11303#comment:14>
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