quirk in "sample" (PR#8264)

Hi,
There is a property of "sample" that I believe is undesirable,
at least for me.
sample(1:3,1) 
chooses from the set {1,2,3}
but 
sample(3:3,1) 
chooses also from {1,2,3} even though
it would be used to sample from an interval [a,b] in general.
So  a program that generates an interval [a,b] for sampling will behave
differently when the endpoints are the same than when
the endpoints are different.

Ian