presto-main/src/main/java/io/prestosql/sql/analyzer/ExpressionAnalyzer.java/ExpressionAnalyzer/getCaseResultExpressions
class ExpressionAnalyzer:        private List<Expression> getCaseResultExpressions(List<WhenClause> whenClauses, Optional<Expression> defaultValue)
        {
            List<Expression> resultExpressions = new ArrayList<>();
            for (WhenClause whenClause : whenClauses) {
                resultExpressions.add(whenClause.getResult());
            }
            defaultValue.ifPresent(resultExpressions::add);
            return resultExpressions;
        }