title: Warning "Redefining module" when file is containing 2 Modules
body: <p>Trying to figure out why below code is generating warning</p>
  
  <pre><code>defmodule A do                                                                                                                                                
   def greet do
     IO.puts "Inside A"
   end
  end
  
  defmodule B do
    def greet do
      IO.puts "Inside B"
    end
  end
  
  spawn(A, :greet, [])
  </code></pre>
  
  <p>Output</p>
  
  <pre><code>iex(14)&gt; c("te.ex")
   te.ex:1: redefining module A
   te.ex:7: redefining module B
   Inside A
   [B, A]
  </code></pre>