Hibernate supports row value constructor syntax, so if the grammar gets extended to something like

vectorCountExpr
: COMMA! countExpr (COMMA! countExpr)*
;
countExpr
: path | collectionExpr | NUM_INT | caseExpression
;
| COUNT^ OPEN! ( STAR { #STAR.setType(ROW_STAR); } | ( ( DISTINCT | ALL )? vectorCountExpr ) ) CLOSE!

at least the parsing of HQL queries like the following would work.

    select
        count((b.id, b.name))
    from
        A a

The double braces syntax might be confusing, but this actually would create a row value which some databases support. There exist workarounds for databases that don't support it but that kind of depends on fixing HHH-9332