Not using schema types

XSLT 2.0 provides built-in XML Schema types (xs:string, xs:integer, etc.) that make type expectations explicit and enable stronger compile-time validation. Not using them when working in XSLT 2.0 mode misses this benefit.

Incorrect:

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="html"/>
  <xsl:template match="/">
    <xsl:variable name="count" select="count(item)"/>
  </xsl:template>
</xsl:stylesheet>

Correct:

<xsl:stylesheet version="2.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xsl:output method="html"/>
  <xsl:template match="/">
    <xsl:variable name="count" as="xs:integer" select="count(item)"/>
  </xsl:template>
</xsl:stylesheet>