<test-case name="try-catch-variable-binding-outside-4" xmlns="http://www.w3.org/2010/09/qt-fots-catalog">
    <description>If a variable reference is used in a try clause, errors raised by binding a value to the variable are not caught unless the binding expression occurs within the try clause.</description>
    <created by="Ghislain Fourny" on="2011-07-28"/>
    <environment ref="err"/>
    <test><![CDATA[try { for $x as xs:integer in (0, 1, "") return $x } catch err:XPTY0004 { 0 }]]></test>
    <result>
      <assert-eq>0</assert-eq>
    </result>
  </test-case>

Implementations may be able to detect XPTY0004 and raise it during static evaluation. Here is one way to prevent detection during static evaluation:

   declare variable $str external := "";
   try {
      for $x as xs:integer in (0, 1, $str)
      return $x
   } catch err:XPTY0004 {
      0
   }