title: Why does scala convert Seq to List?
body: <pre><code>&gt; val a:Seq[Integer] = Seq(3,4)
  a: Seq[Integer] = List(3, 4)
  </code></pre>
  
  <p>If <code>Seq</code> is only a trait, why does the compiler / REPL accept it, and does it behave like that for many other traits or even abstract classes?</p>