uniqueName function may still have conflict names

[Enzo-Liu]

I think the key in Names should not be the raw name. but the generated new name.
uniqueName function

Like follows in ghci

λ> let supply = Map.empty
λ> let (n1,supply1) = uniqueName "abc" supply
λ> let (n2,supply2) = uniqueName "abc" supply1
λ> let (n3,supply3) = uniqueName "abc1" supply2
λ> n3
"abc1"
λ> n2
"abc1"
λ> n1
"abc"

Just to make sure, this is not the wanted behavior, right?