Declaring an interface in a php file followed by a class that implements it errors

I am getting a 255 error and can not work out why

<?php

print "1 \n";
$a = new myClass("a");
print "2 \n";



interface Interabc
{
    public function test($item);
}

class myClass implements Interabc
{
    public function test($item)
    {
        print "test";
    }
}

The output I am getting is:

1 

Process finished with exit code 255

All the code is one file. I am calling it from the command line.

If you are running this in a single file then your class needs to be declared before you instantiate it.

<?php   
interface Interabc
{
    public function test($item);
}

class myClass implements Interabc
{
    public function test($item)
    {
        print "test";
    }
}

print "1 \n";
$a = new myClass();
print "2 \n";