cvs commit: fptools/ghc/compiler/typecheck TcMatches.lhs

[Simon Peyton Jones]

simonpj     2001/10/22 04:37:45 PDT

  Modified files:
    ghc/compiler/typecheck TcMatches.lhs 
  Log:
  	-------------------------------
  	Correct a nasty existential bug
  	-------------------------------
  
  	MERGE WITH STABLE BRANCH
  
  Thanks to Volker Stolz for finding this existential bug.
  Again, it's amazing that it hasn't shown up before.
  GHC 5.02 allows this utterly bogus program to get past
  the type checker
  
    data DS = forall a. C (a -> Int)
  
    call (C f) arg = f arg
  
  The existential-tyvar-escape check was wrong. Easily fixed, though.
  
  	tcfail099 now tests for this
  
  Revision  Changes    Path
  1.53      +14 -6     fptools/ghc/compiler/typecheck/TcMatches.lhs