| CAUSE | It is a static error if an updating expression is used in any position other than one of the following: 1. The topmost expression in the body of a query. 2. The modify clause of a transform expression. 3. The return clause of a FLWOR expression. 4. The return clauses of a typeswitch expression in which every return clause contains an updating expression, an empty expression ( ), or a call to the fn: error function. 5. The then and else clauses of a conditional statement in which both the then and else clauses contain either an updating expression, an empty expression ( ), or a call to the fn: error function. 6. An operand of a comma expression in which each operand is either an updating expression, an empty expression ( ), or a call to the fn: error function. 7. The content of a parenthesized expression. 8. The body of a function declaration in which the keyword updating is specified. |