(See also issue 476.)
The size requested by an array allocation is computed by multiplying the number of elements requested by the size of each element and adding an implementation-specific amount for overhead. It is possible for this calculation to overflow. Is an implementation required to detect this situation and, for instance, throw std::bad_alloc?
On one hand, the maximum allocation size is one of the implementation limits specifically mentioned in Annex Clause Annex B [implimits], and, according to 4.1 [intro.compliance] paragraph 2, an implementation is only required to "accept and correctly execute" programs that do not violate its resource limits.
On the other hand, it is difficult or impossible for user code to detect such overflows in a portable fashion, especially given that the array allocation overhead is not fixed, and it would be a service to the user to handle this situation gracefully.