Well, the `xs:decimal` example is quite interesting. In the XML Schema specification on xs:decimal (<a href="http:&#x2F;&#x2F;www.w3.org&#x2F;TR&#x2F;xmlschema-2&#x2F;#decimal" rel="nofollow">http:&#x2F;&#x2F;www.w3.org&#x2F;TR&#x2F;xmlschema-2&#x2F;#decimal</a>), you&#x27;ll see the following note:<p>All minimally conforming processors must support decimal numbers with a minimum of 18 decimal digits (i.e., with a totalDigits of 18).<p>You have 32 decimal digits in 1.0000000000000000000000000000001, so &quot;minimally conforming processors&quot; are, according to spec, actually free to drop everying after 17th place after comma in this case.<p>You say &quot;constraints of the type are undefined&quot;. I don&#x27;t see how &quot;double-precision 64-bit format IEEE 754 value&quot; from ECMAScript spec is lesser defined than &quot;decimal numbers with a minimum of 18 decimal digits&quot;.