Binding issue with eval_quoted and quote/unquote

test.ex

defmodule P do
  defmacro precompile(call, block) do
    { expr, _ } = Code.eval_quoted(block[:do], [], __CALLER__)
    quote do
      def unquote(call) do
        unquote(expr)
      end
    end
  end
end

defmodule Mod do
  defmacro square(n) do
    quote do
      n = unquote(n)
      n * n
    end
  end
end

defmodule Test do
  import P
  require Mod

  defmacro another_square(n) do
    quote do
      n = unquote(n)
      n * n
    end
  end


  precompile working do
    quoted = quote do
      x = 12
      Mod.square(x)
    end
    [2 * 3, quoted]
  end

  precompile not_working1 do
    quoted = quote do
      x = 12
      another_square(x)
    end
    [2 * 3, quoted]
  end

  precompile not_working2 do
    quoted = quote do
      x = 12
      Test.another_square(x)
    end
    [2 * 3, quoted]
  end

end