Apache resigns from the Java Community Process executive committee

While of course you're exactly right that calling the destructor on Foo when the instance is of Bar is a bad mistake to make, your *particular* example, at least with gcc, will not cause a memory leak. That is simply because Bar's destructor doesn't do anything. The only action taken, in the end, is to call free(my_foo), which works perfectly well and still releases all the memory when my_foo is a "Bar" object rather than the Foo object it is declared to be.

Now, if, instead of "int b;", you'd put "std::string b;" as the member of Bar, then you'd have an actual leak. :)