Saxon » SaxonJS

I'm afraid it's not very helpful, but immediately above the line that issues this message, there is a comment:

// TODO: how to issue warning messages? How to add location?

I can try to explain what the message means, but I can't tell where it comes from (though we might be able to find out if you send us a repro).

The message is produced at compile time, during static type checking, when there's an expression of the form $X = $Y, where the inferred type of $X is xs:integer* while the inferred type of $Y is xs:string*. The message is telling you that the expression will fail with a dynamic error, except in the special case where either $X or $Y is an empty sequence (in which case it will return false).

Thanks Michael.

I went old school and pulled out chunks of code until the errors went away. It was indeed an "if test". Would be great if that ToDo could make it to the top of the pile since it's hard to track these things down otherwise without a lot of debugging.

Regards John

PS Slightly in awe to get a reply from you! You're Wrox XSLT guides have been programming companions for more than 20 years.