When you try to assert something in a file which includes dbclient.h, the mongo assert replaces other asserts which may have been declared.

EXAMPLE:

foo.cc:
#include <cassert>
#include <mongo/client/dbclient.h>

int main() {
assert(false);
}

YIELDS:

> g++ foo.cc -o foo
foo.cc: In function 'int main()':
foo.cc:5: error: 'asserted' was not declared in this scope