Allow restricted higher-rank polymorphism about kitten HOT 2 CLOSED

Why not this?

def trip (a a (a a -> a) -> (a & a & a)):
  -> { a b f }
  a b f@  // fat
  dup dup
  pair pair

Or is it just a bad example?

from kitten.

There is already a workaround for it:

def trip (a a (a a -> a) -> (a & a & a)):
  -> { a b c }
  a b f@ -> x
  a b f@ -> y
  a b f@ -> z
  x y z pair pair

But the behavior that most would probably expect would be for invocations of f to still be valid when applied multiple times, the same way any normal local can be pushed onto the stack multiple times after it is bound.

from kitten.