patch applied (ghc): Fix constructor-specialisation bug

[Simon Peyton Jones]

Thu May  4 04:21:31 PDT 2006  simonpj at microsoft.com
  * Fix constructor-specialisation bug
  
  The constructor-specialisation optimisation was not dealing with the case
  of 
  	(letrec ... in f) a1 a2
  
  We need to apply constructor specialisation in the letrec; previously
  we were leaving it untouched on the grounds that the function part of
  an application is almost always a variable.
  
  But in fact, float-in immediately precedes SpecConstr, so we can get
  these odd-looking applications.
  
  

    M ./compiler/specialise/SpecConstr.lhs -12 +17