Comment by coryrc

What's worse is:

    x = 1;
    a = 2;
    echo(x);
    x = a;

Errors out with "line 1: a is not defined", because the override is implemented as is the tokens were present wherever the first declaration is. (If anybody looks up me, you'll see I've made a bunch of contributions and bitched about this particular thing which really fucks up a bunch of optimizations you'd want to do)