I'm trying to figure out why the code "(| x =  |) x value" throws this
error "cannot run a block after its enclosing method has returned."
What object exactly is the block's enclosing method, and when is it created?
My best guess would be that when "" is evaluated to be placed in slot x,
it is actually evaluated in the context of a new empty method activation
I realize that this code isn't really useful (it throws an error after
all), but I am just trying to better understand what Self is doing.