presto-parser/src/main/java/io/prestosql/sql/tree/ExpressionTreeRewriter.java/ExpressionTreeRewriter/visitTryExpression
class ExpressionTreeRewriter:        @Override
        public Expression visitTryExpression(TryExpression node, Context<C> context)
        {
            if (!context.isDefaultRewrite()) {
                Expression result = rewriter.rewriteTryExpression(node, context.get(), ExpressionTreeRewriter.this);
                if (result != null) {
                    return result;
                }
            }

            Expression expression = rewrite(node.getInnerExpression(), context.get());

            if (node.getInnerExpression() != expression) {
                return new TryExpression(expression);
            }

            return node;
        }