Notes from October 2002 meeting:

We believe that study of 17.6.3.2 [new.delete.single] paragraphs 12 and 13, 17.6.3.3 [new.delete.array] paragraphs 11 and 12, and 6.7.6.5.3 [basic.stc.dynamic.deallocation] paragraph 3 shows that the system-provided operator delete functions must accept a null pointer and ignore it. Those sections also show that a user-written replacement for the system-provided operator delete functions must accept a null pointer. There is no requirement that such functions ignore a null pointer, which is okay -- perhaps the reason for replacing the system-provided functions is to do something special with null pointer values (e.g., log such calls and return).

We believe that the standard should not require an implementation to call a delete function with a null pointer, but it must allow that. For the system-provided delete functions or replacements thereof, the standard already makes it clear that the delete function must accept a null pointer. For class-specific delete functions, we believe the standard should require that such functions accept a null pointer, though it should not mandate what they do with null pointers.

7.6.2.9 [expr.delete] needs to be updated to say that it is unspecified whether or not the operator delete function is called with a null pointer, and 6.7.6.5.3 [basic.stc.dynamic.deallocation] needs to be updated to say that any deallocation function must accept a null pointer.