Drop support for kind constraints.wip/p547

This implements proposal 547 and closes ticket #22298.
See the proposal and ticket for motivation.

Compiler perf improves a bit

Metrics: compile_time/bytes allocated
-------------------------------------
  CoOpt_Singletons(normal)   -2.4% GOOD
            T12545(normal)   +1.0%
            T13035(normal)  -13.5% GOOD
            T18478(normal)   +0.9%
            T9872d(normal)   -2.2% GOOD

                 geo. mean   -0.2%
                 minimum    -13.5%
                 maximum     +1.0%

Metric Decrease:
    CoOpt_Singletons
    T13035
    T9872d

4 files changed, 2 insertions, 66 deletions

diff --git a/testsuite/tests/typecheck/should_compile/T13871.hs b/testsuite/tests/typecheck/should_compile/T13871.hs
deleted file mode 100644
index fa233247ca..0000000000
--- a/testsuite/tests/typecheck/should_compile/T13871.hs
+++ /dev/null
@@ -1,16 +0,0 @@
-{-# LANGUAGE Haskell2010 #-}
-{-# LANGUAGE ConstraintKinds #-}
-{-# LANGUAGE GADTs #-}
-{-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE DataKinds, PolyKinds #-}
-{-# LANGUAGE TypeOperators #-}
-module Foo where
-
-import Data.Kind
-
-data Foo (a :: Type) (b :: Type) where
-  MkFoo :: (a ~ Int, b ~ Char) => Foo a b
-
-data family Sing (a :: k)
-data SFoo (z :: Foo a b) where
-  SMkFoo :: SFoo MkFoo
diff --git a/testsuite/tests/typecheck/should_compile/T15141.hs b/testsuite/tests/typecheck/should_compile/T15141.hs
deleted file mode 100644
index c0cb5d8488..0000000000
--- a/testsuite/tests/typecheck/should_compile/T15141.hs
+++ /dev/null
@@ -1,35 +0,0 @@
-{-# LANGUAGE PolyKinds, TypeFamilies, TypeFamilyDependencies,
-             ScopedTypeVariables, TypeOperators, GADTs,
-             DataKinds #-}
-
-module T15141 where
-
-import Data.Type.Equality
-import Data.Proxy
-
-type family F a = r | r -> a where
-  F () = Bool
-
-data Wumpus where
-  Unify :: k1 ~ F k2 => k1 -> k2 -> Wumpus
-
-f :: forall k (a :: k). k :~: Bool -> ()
-f Refl = let x :: Proxy ('Unify a b)
-             x = undefined
-         in ()
-
-{-
-We want this situation:
-
-forall[1] k[1].
-  [G] k ~ Bool
-  forall [2] ... . [W] k ~ F kappa[2]
-
-where the inner wanted can be solved only by taking the outer
-given into account. This means that the wanted needs to be floated out.
-More germane to this bug, we need *not* to generalize over kappa.
-
-The code above builds this scenario fairly exactly, and indeed fails
-without the logic in kindGeneralize that excludes constrained variables
-from generalization.
--}
diff --git a/testsuite/tests/typecheck/should_compile/T17021a.hs b/testsuite/tests/typecheck/should_compile/T17021a.hs
index aa78cb2959..41eb3f9d92 100644
--- a/testsuite/tests/typecheck/should_compile/T17021a.hs
+++ b/testsuite/tests/typecheck/should_compile/T17021a.hs
@@ -9,16 +9,5 @@ import GHC.Exts
 type family Id x where
   Id x = x
 
---type LevId :: TYPE (Id LiftedRep) -> TYPE (Id LiftedRep)
---newtype LevId x = MkLevId x
-
-type LevId2 :: (r ~ Id LiftedRep) => TYPE r -> TYPE r
-newtype LevId2 x = MkLevId2 x
-
-{-
-MkLevId2 :: forall (r :: RuntimeRep).
-            forall (c :: r ~ Id LiftedRep) ->    -- c is a TyVar
-            forall (x :: TYPE r).
-            x -> LevId2 @r @c x
-
--}
\ No newline at end of file
+type LevId :: TYPE (Id LiftedRep) -> TYPE (Id LiftedRep)
+newtype LevId x = MkLevId x
diff --git a/testsuite/tests/typecheck/should_compile/all.T b/testsuite/tests/typecheck/should_compile/all.T
index 577ce86d65..0a1edfa866 100644
--- a/testsuite/tests/typecheck/should_compile/all.T
+++ b/testsuite/tests/typecheck/should_compile/all.T
@@ -588,7 +588,6 @@ test('T13785', normal, compile, [''])
 test('T13804', normal, compile, [''])
 test('T13822', js_broken(22364), compile, [''])
 test('T13848', normal, compile, [''])
-test('T13871', normal, compile, [''])
 test('T13879', normal, compile, [''])
 test('T13881', normal, compile, [''])
 test('T18851d', normal, compile, [''])
@@ -655,7 +654,6 @@ test('T15431', normal, compile, [''])
 test('T15431a', normal, compile, [''])
 test('T15428', normal, compile, [''])
 test('T15412', normal, compile, [''])
-test('T15141', normal, compile, [''])
 test('T15473', normal, compile_fail, [''])
 test('T15499', normal, compile, [''])
 test('T15586', normal, compile, [''])