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copied!<p>This is no bug. <code>Array</code> is not covariant. B being a subtype of B does not make Array[B] a subtype of Array[A]. This is contrary to java, where B[] is a subtype of A[], which is unsound:</p> <pre><code>A[] b = new B[1]; b[0] = new (A); -> ArrayStoreException </code></pre> <p>So your Array[Some[Any]] is not an Array[Option[Any]]. You must make sure you have an Array[Option], which you may do with</p> <pre><code>val row2 = Array[Option[Any]](Some(test2), Some(12345)) </code></pre> <p>You can also use a type abscription on one of the item:</p> <pre><code>val row2 = Array(Some(test2): Option[String], Some(12345)) </code></pre> <p>Or if you know your values are non-null, </p> <pre><code>val row2 = Array(Option(test2), Option(12345)) </code></pre> <p>(It's enough to do that on one of the value)</p> <p><code>List</code>, on the other hand is covariant, which is why it works. </p> <p>It is actually unfortunate that the more precise type <code>Some</code> is inferred, it is quite uncommon that you want the type of something to be known as <code>Some</code> (or <code>None</code>) rather than <code>Option</code>.</p> <p><strong>Edit</strong> Sorry, looks like I completely missed the point, about why there are different. <code>Array</code> is not covariant, but Iterable is. So it would seems that <code>Array[B]</code> while not being an <code>Array[A]</code>, should be an <code>Iterable[A]</code>, then everything should work. It would be so if Array was a subtype of Iterable. It is not, it comes with the JVM, cannot be made to extend <code>Iterable</code>. What there is is an implicit conversion to <code>WrappedArray</code>, which is an <code>Iterable</code>. </p> <p>When you write <code>val l = List(row1, row2)</code>, it has no reason to apply this conversion. It types list as precisely as it can. Then the fact that List is covariant (a List[B] is a List[A] if B is an A) will not kick in when we have not B is an A, but B has an implicit conversion to A. </p> <p>On the other hand, when you write val l: List[Iterable[A]] = List(x,y) then the List(...) function expects Iterable[A] arguments, and at this point it looks for implicit conversions. </p> <p>Still not a bug, but trickier than I thought. Maybe you could do a </p> <pre><code>class Container[T <% Iterable[Option[Any]]](val rows: Iterable[T]) </code></pre>

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