Generalize kind of the (->) tycon

This is generalizes the kind of `(->)`, as discussed in #11714.

This involves a few things,

 * Generalizing the kind of `funTyCon`, adding two new `RuntimeRep`
binders,
  ```lang=haskell
(->) :: forall (r1 :: RuntimeRep) (r2 :: RuntimeRep)
               (a :: TYPE r1) (b :: TYPE r2).
        a -> b -> *
  ```

 * Unsaturated applications of `(->)` are expressed as explicit
`TyConApp`s

 * Saturated applications of `(->)` are expressed as `FunTy` as they are
currently

 * Saturated applications of `(->)` are expressed by a new `FunCo`
constructor in coercions

 * `splitTyConApp` needs to ensure that `FunTy`s are split to a
`TyConApp`
   of `(->)` with the appropriate `RuntimeRep` arguments

 * Teach CoreLint to check that all saturated applications of `(->)` are
represented with `FunTy`

At the moment I assume that `Constraint ~ *`, which is an annoying
source of complexity. This will
be simplified once D3023 is resolved.

Also, this introduces two known regressions,

`tcfail181`, `T10403`
=====================
Only shows the instance,

    instance Monad ((->) r) -- Defined in ‘GHC.Base’

in its error message when -fprint-potential-instances is used. This is
because its instance head now mentions 'LiftedRep which is not in scope.
I'm not entirely sure of the right way to fix this so I'm just accepting
the new output for now.

T5963 (Typeable)
================

T5963 is now broken since Data.Typeable.Internals.mkFunTy computes its
fingerprint without the RuntimeRep variables that (->) expects. This
will be fixed with the merge of D2010.

Haddock performance
===================

The `haddock.base` and `haddock.Cabal` tests regress in allocations by
about 20%. This certainly hurts, but it's also not entirely unexpected:
the size of every function type grows with this patch and Haddock has a
lot of functions in its heap.

9 files changed, 15 insertions, 16 deletions

diff --git a/testsuite/tests/ghci/scripts/T8535.stdout b/testsuite/tests/ghci/scripts/T8535.stdout
index 7245bf2d3d..2aea35f3de 100644
--- a/testsuite/tests/ghci/scripts/T8535.stdout
+++ b/testsuite/tests/ghci/scripts/T8535.stdout
@@ -1,4 +1,4 @@
-data (->) a b 	-- Defined in ‘GHC.Prim’
+data (->) (a :: TYPE q) (b :: TYPE r) 	-- Defined in ‘GHC.Prim’
 infixr 0 `(->)`
 instance Monoid b => Monoid (a -> b) -- Defined in ‘GHC.Base’
 instance Applicative ((->) a) -- Defined in ‘GHC.Base’
diff --git a/testsuite/tests/ghci/scripts/ghci020.stdout b/testsuite/tests/ghci/scripts/ghci020.stdout
index 7245bf2d3d..2aea35f3de 100644
--- a/testsuite/tests/ghci/scripts/ghci020.stdout
+++ b/testsuite/tests/ghci/scripts/ghci020.stdout
@@ -1,4 +1,4 @@
-data (->) a b 	-- Defined in ‘GHC.Prim’
+data (->) (a :: TYPE q) (b :: TYPE r) 	-- Defined in ‘GHC.Prim’
 infixr 0 `(->)`
 instance Monoid b => Monoid (a -> b) -- Defined in ‘GHC.Base’
 instance Applicative ((->) a) -- Defined in ‘GHC.Base’
diff --git a/testsuite/tests/ghci/should_run/T10145.stdout b/testsuite/tests/ghci/should_run/T10145.stdout
index 7245bf2d3d..2aea35f3de 100644
--- a/testsuite/tests/ghci/should_run/T10145.stdout
+++ b/testsuite/tests/ghci/should_run/T10145.stdout
@@ -1,4 +1,4 @@
-data (->) a b 	-- Defined in ‘GHC.Prim’
+data (->) (a :: TYPE q) (b :: TYPE r) 	-- Defined in ‘GHC.Prim’
 infixr 0 `(->)`
 instance Monoid b => Monoid (a -> b) -- Defined in ‘GHC.Base’
 instance Applicative ((->) a) -- Defined in ‘GHC.Base’
diff --git a/testsuite/tests/partial-sigs/should_compile/T10403.stderr b/testsuite/tests/partial-sigs/should_compile/T10403.stderr
index 0588c1b5bc..3027d17d1b 100644
--- a/testsuite/tests/partial-sigs/should_compile/T10403.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/T10403.stderr
@@ -41,7 +41,8 @@ T10403.hs:22:15: warning: [-Wdeferred-type-errors (in -Wdefault)]
         instance Functor IO -- Defined in ‘GHC.Base’
         instance Functor (B t) -- Defined at T10403.hs:10:10
         instance Functor I -- Defined at T10403.hs:6:10
-        ...plus four others
+        ...plus three others
+        ...plus one instance involving out-of-scope types
         (use -fprint-potential-instances to see them all)
     • In the second argument of ‘(.)’, namely ‘fmap (const ())’
       In the expression: H . fmap (const ())
diff --git a/testsuite/tests/perf/compiler/all.T b/testsuite/tests/perf/compiler/all.T
index 0592bd6800..5f898fbbee 100644
--- a/testsuite/tests/perf/compiler/all.T
+++ b/testsuite/tests/perf/compiler/all.T
@@ -737,13 +737,14 @@ test('T9675',
 test('T9872a',
      [ only_ways(['normal']),
        compiler_stats_num_field('bytes allocated',
-          [(wordsize(64), 3134866040    , 5),
+          [(wordsize(64), 3304620816, 5),
           # 2014-12-10    5521332656    Initally created
           # 2014-12-16    5848657456    Flattener parameterized over roles
           # 2014-12-18    2680733672    Reduce type families even more eagerly
           # 2015-12-11    3581500440    TypeInType (see #11196)
           # 2016-04-07    3352882080    CSE improvements
           # 2016-10-19    3134866040    Refactor traceRn interface (#12617)
+          # 2017-02-01    3304620816
            (wordsize(32), 1740903516, 5)
           # was           1325592896
           # 2016-04-06    1740903516    x86/Linux
diff --git a/testsuite/tests/perf/haddock/all.T b/testsuite/tests/perf/haddock/all.T
index 5ed6758cfc..4c641d5828 100644
--- a/testsuite/tests/perf/haddock/all.T
+++ b/testsuite/tests/perf/haddock/all.T
@@ -5,7 +5,7 @@
 test('haddock.base',
      [unless(in_tree_compiler(), skip), req_haddock
      ,stats_num_field('bytes allocated',
-          [(wordsize(64), 32695562088, 5)
+          [(wordsize(64), 38425793776, 5)
             # 2012-08-14:  5920822352 (amd64/Linux)
             # 2012-09-20:  5829972376 (amd64/Linux)
             # 2012-10-08:  5902601224 (amd64/Linux)
@@ -33,6 +33,7 @@ test('haddock.base',
             # 2017-01-11: 31115778088 (x86_64/Linux) - Join points (#12988)
             # 2017-02-11: 34819979936 (x86_64/Linux) - OccurAnal / One-Shot  (#13227)
             # 2017-02-16: 32695562088 Better Lint for join points
+            # 2017-02-17: 38425793776 (x86_64/Linux) - Generalize kind of (->)
 
           ,(platform('i386-unknown-mingw32'), 4434804940, 5)
             # 2013-02-10:                     3358693084 (x86/Windows)
@@ -55,7 +56,7 @@ test('haddock.base',
 test('haddock.Cabal',
      [unless(in_tree_compiler(), skip), req_haddock
      ,stats_num_field('bytes allocated',
-          [(wordsize(64), 23867276992, 5)
+          [(wordsize(64), 27784875792, 5)
             # 2012-08-14:  3255435248 (amd64/Linux)
             # 2012-08-29:  3324606664 (amd64/Linux, new codegen)
             # 2012-10-08:  3373401360 (amd64/Linux)
@@ -98,6 +99,7 @@ test('haddock.Cabal',
             # 2017-01-14: 23272708864 (amd64/Linux) - Join points (#12988)
             # 2017-02-11: 25533642168 (amd64/Linux) - OccurAnal / One-Shot  (#13227)
             # 2017-02-16: 23867276992  Better Lint for join points
+            # 2017-02-17: 27784875792 (amd64/Linux) - Generalize kind of (->)
 
           ,(platform('i386-unknown-mingw32'), 3293415576, 5)
             # 2012-10-30:                     1733638168 (x86/Windows)
diff --git a/testsuite/tests/typecheck/should_compile/all.T b/testsuite/tests/typecheck/should_compile/all.T
index c44ab9153c..8a5610d848 100644
--- a/testsuite/tests/typecheck/should_compile/all.T
+++ b/testsuite/tests/typecheck/should_compile/all.T
@@ -167,7 +167,7 @@ test('tc163', normal, compile, [''])
 test('tc164', normal, compile, [''])
 test('tc165', expect_broken_for(10181, ['optasm', 'optllvm']), compile, [''])
 test('tc166', normal, compile, [''])
-test('tc167', normal, compile_fail, [''])
+test('tc167', normal, compile, [''])
 test('tc168', normal, compile_fail, [''])
 test('tc169', normal, compile, [''])
 
diff --git a/testsuite/tests/typecheck/should_compile/tc167.stderr b/testsuite/tests/typecheck/should_compile/tc167.stderr
deleted file mode 100644
index 634b50dd5b..0000000000
--- a/testsuite/tests/typecheck/should_compile/tc167.stderr
+++ /dev/null
@@ -1,6 +0,0 @@
-
-tc167.hs:8:15:
-    Expecting a lifted type, but ‘Int#’ is unlifted
-    In the first argument of ‘(->)’, namely ‘Int#’
-    In the type ‘(->) Int#’
-    In the type declaration for ‘T’
diff --git a/testsuite/tests/typecheck/should_fail/tcfail181.stderr b/testsuite/tests/typecheck/should_fail/tcfail181.stderr
index 30e27b8bb7..3ab08676b5 100644
--- a/testsuite/tests/typecheck/should_fail/tcfail181.stderr
+++ b/testsuite/tests/typecheck/should_fail/tcfail181.stderr
@@ -9,8 +9,9 @@ tcfail181.hs:17:9: error:
       These potential instances exist:
         instance Monad IO -- Defined in ‘GHC.Base’
         instance Monad Maybe -- Defined in ‘GHC.Base’
-        instance Monad ((->) r) -- Defined in ‘GHC.Base’
-        ...plus two others
+        instance Monoid a => Monad ((,) a) -- Defined in ‘GHC.Base’
+        ...plus one other
+        ...plus one instance involving out-of-scope types
         (use -fprint-potential-instances to see them all)
     • In the expression: foo
       In the expression: foo {bar = return True}