[GHC] #11722: No TypeRep for unboxed tuples

[GHC]

#11722: No TypeRep for unboxed tuples
-------------------------------------+-------------------------------------
           Reporter:  goldfire       |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 This now crashes on GHC HEAD:

 {{{#!hs
 {-# LANGUAGE MagicHash #-}
 {-# LANGUAGE UnboxedTuples #-}
 module Main where

 import Data.Typeable
 import GHC.Exts

 main :: IO ()
 main = print $ typeOf (Proxy :: Proxy (# Int, Int #))
 }}}

 {{{
 $ /opt/ghc/head/bin/ghc -O2 -fforce-recomp Example.hs
 [1 of 1] Compiling Main             ( Example.hs, Example.o )
 ghc: panic! (the 'impossible' happened)
   (GHC version 8.1.20160317 for x86_64-unknown-linux):
         tyConRep (#,#)

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
 }}}

 (Previously, this was rejected with an error message, since you couldn't
 put an unlifted type as the argument of `Proxy`.)

 (Copied from comment:28:ticket:11471.)

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11722>
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