Confusing error messages for vector-set!/vector-ref

[leppie]

Both of these are a bit confusing:

> (vector-set! (vector 0) 0.0 #f)
Unhandled exception
 Condition components:
   1. &assertion
   2. &who: bitwise-and
   3. &message: "not an exact integer"
   4. &irritants: (-1.0)

> (vector-ref (vector 0) 0.0)
Unhandled exception
 Condition components:
   1. &assertion
   2. &who: vector-ref
   3. &message: "not a valid index"
   4. &irritants: (0.0)

[Abdulaziz Ghuloum (aghuloum)]

The first error for vector-set! was a compile-time error, and is fixed in revision 1737.

What's wrong with the second (vector-ref) error?