[GHC] #7445: template-haskell : the impossible happened

[GHC]

#7445: template-haskell : the impossible happened
-------------------------------+--------------------------------------------
Reporter:  erikd               |          Owner:                  
    Type:  bug                 |         Status:  new             
Priority:  normal              |      Component:  Template Haskell
 Version:  7.4.2               |       Keywords:                  
      Os:  Unknown/Multiple    |   Architecture:  Unknown/Multiple
 Failure:  Compile-time crash  |      Blockedby:                  
Blocking:                      |        Related:                  
-------------------------------+--------------------------------------------
 Will attach two files to this bug, quasi-arithmetic.hs and QuasiArith.hs.

 Running:

 {{{
 ghc --make quasi-arithmetic.hs -o quasi-arithmetic
 }}}

 on these files results in:

 {{{
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.4.2 for x86_64-unknown-linux):
         mkUsage
     main:QuasiArith BinopExpr{d}[(0B, base:System.IO.print{v 0B}),
                                   (32I, ghc-prim:GHC.Types.IO{tc 32I}),
                                   (40, ghc-prim:GHC.Tuple.(){(w) tc 40}),
                                   (rwP, main:QuasiArith.MulOp{d rwP}),
                                   (rwR, main:QuasiArith.AddOp{d rwR}),
                                   (rwU, main:QuasiArith.BinopExpr{d rwU}),
                                   (rwW, main:QuasiArith.IntExpr{d rwW}),
                                   (r2Ha, main:Main.main{v r2Ha})]
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7445>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler