Iterate an array with index in Swift 3
<p>I'm trying to iterate an array with an index in Swift 3 but keep getting</p>

<blockquote>
  <p>Expression type '[Int]' is ambiguous without more context</p>
</blockquote>

<p>this is reproducible with the following example in a playground:</p>

<pre><code>var a = [Int]()
a.append(1)
a.append(2)
// Gives above error
for (index, value) in a {
  print("\(index): \(value)")
}
</code></pre>

<p>I'm not sure what context it is asking for.</p>