Even though tuples, records and discriminated unions are reference types, they all have the built-in equality properties you would expect in a value type.  For example:

> let a = (1,'a');;

val a : int * char = (1, 'a')

> let b = (1,'a');;

val b : int * char = (1, 'a')

> a = b;;

val it : bool = true

That is, you get the equality behavior you would expect rather than the usual equality behavior associated with reference types.  Here’s an example of records and the built-in equality checking:

> type rec1 = {

a:int

b:string

};;

type rec1 =

{a: int;

b: string;}

> let a = {a=1;b="one"};;

val a : rec1 = {a = 1;

b = "one";}

> let b = {a=1;b="one"};;

val b : rec1 = {a = 1;

b = "one";}

> a = b;;

val it : bool = true