operator ~= { associativity precedence } Declarations func ~= <T : Equatable>(_: T, b: T) Declaration func ~=<T : Equatable>(a: T, b: T) -> Bool func ~= <T>(_: _OptionalNilComparisonType, rhs: T?) Declaration func ~=<T>(lhs: _OptionalNilComparisonType, rhs: T?) -> Bool