Elixir variables that share a same name but are different

variables.exs

ast =
  {:fn, [],
   [
     {:->, [],
      [
        [
          {:a, [counter: 1], nil},
          {:a, [counter: 2], nil}
        ],
        {{:a, [counter: 1], nil}, {:a, [counter: 2], nil}}
      ]}
   ]}

Macro.to_string(ast)
# "fn a, a -> {a, a} end"

{fun, _binding} = Code.eval_quoted(ast)

fun.(:foo, :bar)
# {:foo, :bar}