The problem is that we don't know what the compiler might think.. If I write something along the lines of int& bar = *foo if(!foo) { // do something

The problem is that we don't know what the compiler might think.. If I write something along the lines of int& bar = *foo if(!foo) { // do something } The compiler very well might (and would be perfectly within its rights to) completely eliminate everything inside of the if(!foo) since it can assume the pointer is non-null because it is being dereferenced.