scala> (new Array[Unit](5))(0) == ()
<console>:10: warning: comparing values of types Unit and Unit using `==' will always yield true
       (new Array[Unit](5))(0) == ()
                               ^
res16: Boolean = false

scala> (new Array[Unit](5))(0) == null
<console>:10: warning: comparing values of types Unit and Null using `==' will always yield false
       (new Array[Unit](5))(0) == null
                               ^
res17: Boolean = true

scala> {val a = Array.fill(5)(()); a(0) == ()}
<console>:11: warning: comparing values of types Unit and Unit using `==' will always yield true
       {val a = Array.fill(5)(()); a(0) == ()}
                                        ^
res18: Boolean = true