presto-parser/src/main/java/io/prestosql/sql/parser/SqlParser.java/SqlParser/exitNonReserved
class SqlParser:        @Override
        public void exitNonReserved(SqlBaseParser.NonReservedContext context)
        {
            // we can't modify the tree during rule enter/exit event handling unless we're dealing with a terminal.
            // Otherwise, ANTLR gets confused an fires spurious notifications.
            if (!(context.getChild(0) instanceof TerminalNode)) {
                int rule = ((ParserRuleContext) context.getChild(0)).getRuleIndex();
                throw new AssertionError("nonReserved can only contain tokens. Found nested rule: " + ruleNames.get(rule));
            }

            // replace nonReserved words with IDENT tokens
            context.getParent().removeLastChild();

            Token token = (Token) context.getChild(0).getPayload();
            context.getParent().addChild(new CommonToken(
                    new Pair<>(token.getTokenSource(), token.getInputStream()),
                    SqlBaseLexer.IDENTIFIER,
                    token.getChannel(),
                    token.getStartIndex(),
                    token.getStopIndex()));
        }