Changes to ghc(7)

Changes to ghc:
commit 9c621e9b1c7d8a02b48f06f041da605ce27f4d80
Author: Simon Peyton Jones <simonpj@microsoft.com>
Date:   Thu Jun 19 17:26:11 2014 +0100

    Reject forall types in constraints in signatures

    Fixes Trac #9196.  Thanks to archblob for an initial stab at this.
    In the end I fixed it in the kind checker rather than the subsequent
    validity check, (a) so that the error messages look more uniform,
    and (b) so that I did not need to meddle with isPredTy.

commit 64224f19d1cccd1104e323016a1481ddaa9db464
Author: Simon Peyton Jones <simonpj@microsoft.com>
Date:   Thu Jun 19 14:11:07 2014 +0100

    Comment typo

commit 2e362ddebf2286409b7423d3dd49152117c1ae56
Author: Simon Peyton Jones <simonpj@microsoft.com>
Date:   Thu Jun 19 09:46:24 2014 +0100

    Make splitStrProdDmd (and similarly Use) more robust

    The issue here is avoiding a GHC crash when a program uses
    unsafeCoerce is a dangerous (or even outright-wrong) way.

    See Trac #9208

commit aec9e75bb09f6a99d77d3aeea255229ffb1925fa
Author: Simon Peyton Jones <simonpj@microsoft.com>
Date:   Thu Jun 19 09:44:30 2014 +0100

    Improve documentation of defaulting rules with OverloadedStrings

    See #9206

commit cdc74311a23beef47d1418349d492a17bf62ed6f
Author: Simon Peyton Jones <simonpj@microsoft.com>
Date:   Thu Jun 19 09:24:50 2014 +0100

    Add a new section to the manual about hiding things that a module doesn't export

    See Trac #9216

commit 0ceb84e9668ba05d9a0ec49046ad7b4c2557a484
Author: Simon Peyton Jones <simonpj@microsoft.com>
Date:   Thu Jun 19 09:01:51 2014 +0100

    Tidy up the printing of single-predicate contexts

    This covers things like
       Eq a => blah   and   (?x::Int) => blah
    where there is just one predicate. Previously we used an ad-hoc
    test to decide whether to parenthesise it, but acutally there is
    a much simpler solution: just use the existing precedence mechamism.

    This applies both to Type and HsType.

commit b6693d3096c810b925af1899b45867482bcc81cf
Author: Simon Peyton Jones <simonpj@microsoft.com>
Date:   Wed Jun 18 11:59:30 2014 +0100

    A bit more tracing of functional dependencies