The default type for an otherwise-unconstrained Boolean literal.

    typealias BooleanLiteralType = Bool


    When you create a constant or variable using one of the Boolean literals true or false, the resulting type is determined by the BooleanLiteralType alias. For example:

    let isBool = true
    print("isBool is a '\(type(of: isBool))'")
    // Prints "isBool is a 'Bool'"

    The type aliased by BooleanLiteralType must conform to the ExpressibleByBooleanLiteral protocol.