C++: BufferAccess shouldn't consider expressions in sizeof

[gsingh93]

I have some code like this:

unsigned long foo() {
  char buf[1];
  return sizeof(buf[0]);
}

My understanding is that buf[0] is actually not accessing the buffer, sizeof will just get the sizeof the type without any memory access. Yet this query still returns it as a result:

import cpp
import semmle.code.cpp.security.BufferAccess

from BufferAccess ba
select ba

Is this intended? It results in a few false positives in my queries.