Hi Andrew,

thank you for reporting this. The bug was introduced with the recent
addition of support for the optional prefix in a URIQualifiedName. It
has now been handled by PR 2701 [1], which has since been merged to the
main branch. The fix is also present in the latest snapshot [2].

Best regards,
Gunther

[1] https://github.com/BaseXdb/basex/pull/2701
[2] https://files.basex.org/releases/latest/


On 6/27/2026 6:19 PM, Andrew Sales via BaseX-Talk wrote:
> Hello,
>
> The query:
>
> let $Q{}foo:=1
> return $Q{}foo
>
> produces a syntax error, unless it is amended to:
>
> let $Q{}foo :=1
> return $Q{}foo
>
> (i.e. space inserted before the colon.)
> This first occurs with BaseX 12.1 and with earlier versions did not
> produce a syntax error. For comparison, this syntax error is not
> observed under Saxon XQuery 12.9 or 13.0, or (with Saxon or BaseX) if
> the variable is a QName instead.
>
> Many thanks,
> Andrew