I'm pretty sure it's due to http://es5.github.io/#x10.4.2 http://es5.github.io/#x10.4.2 section 1A. Calling eval like that causes it to be an indirect eval cal

I'm pretty sure it's due to http://es5.github.io/#x10.4.2 http://es5.github.io/#x10.4.2 section 1A. Calling eval like that causes it to be an indirect eval call which results in it being executed in the global context.