patch applied (ghc): FIX #1385: make sure tuple instances are loaded

[Simon Peyton Jones]

Wed Jun  6 06:00:56 PDT 2007  simonpj at microsoft.com
  * FIX #1385: make sure tuple instances are loaded
  
  Typechecking of explicit tuples is done "by hand" (rather than using
  boxySplitTyConApp) so that rigidity is maintained.  In making that change
  I'd forgotten to retain the call to checkWiredInTyCon, which is important
  to make sure instances are brought into scope.
  
  Test is tc227.
  
  

    M ./compiler/typecheck/TcExpr.lhs -3 +5