boolean

Negation of a Boolean singleton type. scala val notFalse: ![false] = true val notTrue: ![true] = false

Conjunction of two Boolean singleton types. scala val a: true && true = true val b: false && true = false

Exclusive disjunction of two Boolean singleton types. scala val a: true true = false val b: false true = true

Disjunction of two Boolean singleton types. scala val a: true || false = true val b: false || false = false