module type Injective2 =sig..end
Injective2 is for a binary type that is injective in both type arguments.type ('a1, 'a2) t
val strip : (('a1, 'a2) t, ('b1, 'b2) t)
Type_equal.equal -> ('a1, 'b1) Type_equal.equal * ('a2, 'b2) Type_equal.equal