It's not out of memory at all. It's (probably) a blown stack during compilation optimization. Modern Py3 has "fixed" this by simply preventing silly levels of literal concatenation like this causing indefinite call stack expansion; the older ones just allowed the call stack to grow out of control (and the stack can blow long before memory is exhausted).

I doubt a fix would be backported, and a fix for Py3 seems unnecessary unless you can come up with a scenario where the recursion depth error is unacceptable (eval-ing arbitrary user input doesn't count, for obvious reasons).