type ('a, 'b) t = ('a, 'b) Base.Type_equal.t =
| T : ('a, 'a) t
runtime witnes of type equality this is a reduced version of
Core.Type_equal
.
type ('a, 'b) equal = ('a, 'b) t
val conv : ('a, 'b) t -> 'a -> 'b
type-safe conversion between equal types
val refl : ('a, 'a) t
type equality is reflexive