See also: http://forum.dlang.org/thread/gfdqabtlqiwatkowmtxy@forum.dlang.org

template A(alias T) {
    alias A = T;
}

void main() {
    struct S { }
    static assert(is(typeof(A!(cast(S*)null)) == S*));
    //pragma(msg, typeof(A!null)); // S*
    static assert(is(typeof(A!(null) == typeof(null)))); // still S*
}