GitLab

There are two main changes

 * New LANGUAGE option RebindableSyntax, which implies NoImplicitPrelude

 * if-the-else becomes rebindable, with function name "ifThenElse"
   (but case expressions are unaffected)

Thanks to Sam Anklesaria for doing most of the work here

This would have produced a more civilised error for Trac #4396

- add link to inno setup docs, so readers don't have to guess what
  ghc.iss might be

- add Task section, and associated most Registry actions with separate
  (sub)tasks, so that file associations, default action, and PATH
  setting can be optional

- copy license file into doc directory

- install icon file again, so that DefaultIcon is no longer a dangling
  pointer (#4352)

- only delete ghc_haskell key if empty (in case there were other tools
  using it)

- add versioned GHCi to right-click menu (to allow for multiple tool installs)

See Note [Localise pattern binders]

We were using the supply's unique, and then passing the same supply to
initUs_, which sounds like a bug waiting to happen.

This is a little nicer than having to explicitly split supplies and
throw half of them away.

Lots of comments with decomposeRuleLhs

We generate intermediate unfoldings which are just thrown away, so
evaluating them is a waste of time.

Update the documentation on using DLL's from Windows, fixing several errors, in particular those relating to bug 3605

(1) More lenient kind checking, (2) Fixed orientation problems and avoiding double unifications, (3) Comments

We weren't doing fundeps for derived superclasses

Fixes a loop in the compiler, when running the dph tests