Question with binding

[Jonathan S. Shapiro <shap@polya.Stanford.EDU>]

I have been thinking about compiling scheme, and am confused about the
following possibility:

	(define foo (lambda (x) (+ x 2)))
	(define + (lambda (x y) something))
	(foo)

If this is legal, I don't understand how a compiler can validly inline
primitives.  Is there some provision in R3RS or R4RS that resolves
this problem, or is it really a problem?  If the latter, how do
compilers deal with it?

Jon