[commit: ghc] master: In type or data instances, check that all variables are bound (e89f3ba)

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/e89f3bac94f513841f46346528183920783ce1f9

>---------------------------------------------------------------

commit e89f3bac94f513841f46346528183920783ce1f9
Author: Simon Peyton Jones <[email protected]>
Date:   Wed Jan 2 08:26:28 2013 +0000

    In type or data instances, check that all variables are bound
    
    Trac #7536 points out that it's possible for the LHS to *look*
    as if it binds variables, but does not acutally do so
    
             type T a = Int
             type instance F (T a) = a
    
    This patch makes it an error.

 compiler/typecheck/TcInstDcls.lhs   |   43 ++++++++++++++++++-----------------
 compiler/typecheck/TcMType.lhs      |   36 ++++++++++++++++++++++-------
 compiler/typecheck/TcTyClsDecls.lhs |   23 ++++++------------
 3 files changed, 57 insertions(+), 45 deletions(-)


Diff suppressed because of size. To see it, use:

    git show e89f3bac94f513841f46346528183920783ce1f9