Exceptions to the rule

The C++ Standard is a pretty large and complex document; however, it is the bible as far as writing C++ code is concerned. The standard is full of exceptions that prove the rule, and this quiz demonstrates just one trivial example.

Question: What, if anything, is wrong with the following code?

Answer: Nothing, it is perfectly valid

Why?

In C++ the return is an optional statement in (and only in) the main function, with 0 being implicitly returned if the return statement is omitted. This is a special case that only applies to the main function.