Lambda the Ultimate

I notice in stack based languages certain symmetric programs reduce to no-ops:

f1 = [swap swap] = []
f2 = [dup pop] = []
f3 = [cons uncons] = [] 
f4 = [dup swap cons uncons swap pop] = [dup swap swap pop] = [dup pop] = []

So how much of this is blindingly obvious to the research community? It seems that this must be much harder to detect in non stack based languages.