Since CTFE (Compile-time function evaluation) can only be tested by running a program or writing a bunch of static asserts, maybe it would be nice, instead of writing lots of static asserts, to be able to write a "static unittest" block. The static unittest blocks are executed at compile time (if they can't be, isue an error) and allow writing "assert" instead of "static assert" inside them (same as in templates you can write "foreach" instead of "static foreach").

More explicitly, instead of writing

static assert (myFunc!("bla1") == "ble2");
static assert (myFunc!("bla3") == "ble4");
static assert (myFunc!("bla5") == "ble6");

you could write:

static unittest {
    assert(myFunc!("bla") == "ble2");
    assert(myFunc!("bla3") == "ble4");
    assert(myFunc!("bla5") == "ble6");
}

Less typing, clearer intention. And the block can contain not only asserts, but any code that can be executed at compile time.