running test VisitorCalc through antlr
java.exe -jar ..\..\antlr4-4.8-2-SNAPSHOT-complete.jar -no-listener -visitor -Dlanguage=Rust .\VisitorCalc.g4
produces code that refernces the listener
here for example in the generated parser
antlr_rust::tid! { impl<'input> TidAble<'input> for dyn VisitorCalcListener<'input> + 'input }