Provided overload to TypeClass::builtinTypeInfo to return true. Shouldn't almost all types have a builtin typeinfo? Maybe it'd be better to have the default at true and only overload typedef and friends.

module bug74;

char[] sformat(char[] s, ...)
{
    TypeInfo[] ti = _arguments;
    void* args = _argptr;
    return "";
}

void main()
{
}