Unwrapped

static struct T {}
static struct U (T) {}

alias V = U!T;
alias W = U!(U!T);

static assert (is (Unwrapped!T == T));
static assert (is (Unwrapped!V == T));
static assert (is (Unwrapped!W == V));
static assert (is (Unwrapped!(Unwrapped!W) == T));