Optint.Conditional
A conditional type equality, used for revealing that a type t has one of two possible implementation types u and v.
t
u
v
type ('t, 'u, 'v) t =
| True : ('t, 't, _) t
therefore 't = 'u
't
'u
| False : ('t, _, 't) t
therefore 't = 'v
'v