patch applied (ghc): Make tyConSingleDataCon_maybe more forgiving

[Simon Peyton Jones]

Thu Oct  8 09:23:29 PDT 2009  simonpj at microsoft.com
  * Make tyConSingleDataCon_maybe more forgiving
  Ignore-this: f60ab4d3e79b2c18499d0bfcf1949c85
  
  This function was barfing on a type family tycon; which in turn
  crashed the compiler (when -ticky is in use) because of the use in
  CmmTicky.hs.  There's no need for it to reject such tycons, so I just
  made it return Nothing rather than falling over.
  

    M ./compiler/types/TyCon.lhs -7 +4

View patch online:
http://darcs.haskell.org/ghc/_darcs/patches/20091008162329-1287e-c2182063c26ca9a7eee4022abe76c161535beaf2.gz