Well it could (and I agree with WalterBright that it should) have been disallowed. a[b] being implemented as an early stage rewrite rule expanding to *(a+b) is an uninteresting implementation detail. And I doubt it is even implemented that way in modern compilers anyway. It certainly can't be in C++ as a[b] and b[a] mean different things when [] is overloaded.
That "uninteresting implementation detail" is actually of grave importance when it comes to understanding how buffer overflow attacks work. I hate to think anyone would put C code into production without understanding this.
