title: Scala query generating invalid SQL
body: <p>I'm using scalaquery to connect to both oracle and postgres servers.
  This behaviour is occuring for both Oracle and Postgres, but it's only valid (and still incorrect) SQL in Postgres.</p>
  
  <p>At some point, I'm running a query in scalaquery of the form:</p>
  
  <pre><code>row.foo.bind == parameter.foo || row.foo inSetBind parameter.foo.children
  </code></pre>
  
  <p>Parameter is a trait, which is known to have a foo in it.</p>
  
  <p>The problem here is that out of the ~100 queries run, scala-query only generates the correct SQL once, of the form</p>
  
  <pre><code>...
  WHERE row.foo = ? or row.foo in (?, ?, ?, ?, ?)
  ...
  </code></pre>
  
  <p>Most of the time it instead generates</p>
  
  <pre><code>...
  WHERE row.foo = ? or false
  ...
  </code></pre>
  
  <p>Why is this happening inconsistently, is it a bug (I assume it is), and how do I work around it?</p>