Make (=>) polykinded (:: k -> k -> Constraint)

Would it be a good idea to treat => in -XQuantifiedConstraints as

type family
  (=>) :: k -> k -> Constraint where
  (=>) = Implies0
  (=>) = Implies1
  (=>) = Implies2 ..

class    (a => b) => Implies a b
instance (a => b) => Implies a b

class    (forall x. f x => g x) => Implies1 f g
instance (forall x. f x => g x) => Implies1 f g

class    (forall x y. f x y => g x y) => Implies2 f g
instance (forall x y. f x y => g x y) => Implies2 f g
..

or will this get too confusing? This means type signatures like the ones from #14942 (closed)

oneTwo   :: (forall x. semi x => Semigroup x) => Free semi Int

nil      :: (forall x. mon  x => Monoid x)    => Free mon Int

together :: (forall x. mon  x => Monoid x)    => [Free mon Int]

could equivalently be written

oneTwo   :: (semi => Semigroup) => Free semi Int

nil      :: (mon  => Monoid)    => Free mon Int

together :: (mon  => Monoid)    => [Free mon Int]

I'm not sold on this idea myself. It's quite possible this would screw with the parser.

Trac metadata

Trac field	Value
Version	8.2.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture