RHS of assignment is evaluated eagerly?

Is this expected behavior, and if so, why? I would have expected
neither 'arg' nor 'value' to evaluate until forced.

`test<-` <- function(obj, arg, value) {
 1 #force no args
}
x <- 1
test(x, print("evaled arg")) <- print("evaluated value")

## [1] "evaluated value?

?Use the source, Luke?:

    /*  It's important that the rhs get evaluated first because                                                                       
        assignment is right associative i.e.  a <- b <- c is parsed as                                                                
        a <- (b <- c).  */

Compare to

`test<-`(x, print("evaled arg"), print("evaluated value"))

[1] 1

Cheers,
Simon