It's bitten me in the ass on occasion:
for (vector::iterator it;
it != v.end(); ++it)
{
it->foo(); // should have been written (*it)->foo();
}
The only time it's acceptable is if the type is meant to be truly opaque and not accessed directly at all. IOW, if someone's going to have to dereference it outside of an API, then the pointerness should not be hidden behind a typedef.
