Issue when running xqdoc with specific attribute names.

[peetkes]

I created a test-case with a function containing a let statement with a specific attribute predicate and ran into an issue with the parser.
I got an error message stating:

line l:p mismatched input '$' expecting {EQUAL, NOT_EQUAL, LBRACKET, RBRACE, STAR, PLUS, MINUS, COMMA, SLASH, DSLASH, VBAR, LANGLE, RANGLE, BANG, ARROW, CONCATENATION, KW_AND, KW_CAST, KW_CASTABLE, KW_DIV, KW_EQ, KW_EXCEPT, KW_GE, KW_GT, KW_IDIV, KW_INSTANCE, KW_INTERSECT, KW_IS, KW_LE, KW_LT, KW_MOD, KW_NE, KW_OR, KW_TO, KW_TREAT, KW_UNION}

when I test the function with ANTLR Preview in IntelliJ I also see a similar error regarding the mismatched input '$'

I think it is caused by the fact that I used a specific attribute name 'previous'

Whenever I test a construct like this:

let $var := fn:empty($element[@previous])
..

I get that error message. As soon as I change it to something else like:

let $var := fn:empty($element[@prev])
..

It will work as expected.
Is there a list of names that cannot be used as parameter names or prdicates?
I noted that I get the same error when I use this:

let $previous := fn:empty($element[@prev])

This gives the same error.

Is that something that should be fixed in the grammar?

Desktop (please complete the following information):

• OS: MacOS
• Browser: Chrome
• IntelliJ Ultimate version: IntelliJ IDEA 2022.2.2 (Ultimate Edition)
• Version [e.g. 22]