Reason: Antlr4 doesn't have syntactic predicate and the parser chooses drlIdentifier rather than new_key creator in primary rule. So far we haven't found a way to prioritize new_key creator, so excluded new from drlIdentifier
There is some difference in parser error messages between Antlr4 and Antlr3 (e.g.mismatched input vs no viable alternative). We don't have much to do, and the difference is not important.
Old parser fails to populate common properties (e.g. startCharacter) in some Descr objects. There is no reason for the new parser to mimic the same failure.
This issue aggregates known backward compatibility issues between new Antlr4 parser and old Antlr3 parser.
newis not included indrlIdentifier. For example,newis not used in a package name (of course, it's not allowed in Java).drlIdentifierrather thannew_key creatorinprimaryrule. So far we haven't found a way to prioritizenew_key creator, so excludednewfromdrlIdentifiermismatched inputvsno viable alternative). We don't have much to do, and the difference is not important.DRLExprParserTestin https://github.com/apache/incubator-kie-drools/pull/5855startCharacter) in some Descr objects. There is no reason for the new parser to mimic the same failure.DescrCommonPropertyTestin https://github.com/apache/incubator-kie-drools/pull/5855