Question

In C++, in the exception declaration specifier, if I declare a base class and then throw a derived class, is that an unexpected exception?

Answer 1

In C++, in the exception declaration specifier, if I declare a base class and then throw a derived class, is that an unexpected exception?

No. It is allowed.

Reference:
C++03 15.4 Exception specifications

Para 6:

An exception-specification can include the same type more than once and can include classes that are related by inheritance, even though doing so is redundant. An exception-specification can also include the class std::bad_exception (18.6.2.1).

There is a relevant example in
Para 8:

[Example:
class X { };
class Y { };
class Z: public X { };
class W { };
void f() throw (X, Y)
{
    int n = 0;
    if (n) throw X(); // OK
    if (n) throw Z(); // also OK    <------- Example of the exact scenario you posted
    throw W(); // will call unexpected()
}
—end example]

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Note that Exception specifications are considered as an experiment that failed and most compilers do not implement them correctly. So avoid(rather don’t) use them.