Assertion failed
assert("Hello, world!" !is String)
                       |
                       false

Assertion failed
assert(" !is " !is String)
               |
               false

Assertion failed
assert(
    " !is "

            !is
            |
            false

            String
)

Assertion failed
assert("Hello, world!"/*!is*/!is/*!is*/String)
                             |
                             false

Assertion failed
assert(("Hello, world!" !is String) !is Boolean)
                        |           |
                        |           false
                        false