getClass() of a Generic Method Parameter in a Java

The following Java method fails to compile:

<T extends Number> void foo(T t)
{
    Class<? extends T> klass = t.getClass();
}

Error received is: Type mismatch: cannot convert from Class<capture#3-of ? extends Number> to Class<? extends T>

Can someone explain why Class<? extends T> is invalid, but Class<? extends Number> is fine?

Javadoc says:

The actual result type is Class<? extends |X|> where |X| is the erasure of the static type of the expression on which getClass is called. For example, no cast is required in this code fragment:

Number n = 0;
Class<? extends Number> c = n.getClass();