Closure equality comparison. Implemented as sameness comparison.
Example
F make_closure() { F(x) x + 1 }; make_closure() == make_closure() # false - different instances
F make_closure() { F(x) x + 1 }; make_closure().ip() == make_closure().ip() # true - same code
f = F(x) x +1; f == f # true - same instance