presto-main/src/main/java/io/prestosql/sql/analyzer/ExpressionAnalyzer.java/Visitor/visitCoalesceExpression
class Visitor:        @Override
        protected Type visitCoalesceExpression(CoalesceExpression node, StackableAstVisitorContext<Context> context)
        {
            Type type = coerceToSingleType(context, "All COALESCE operands must be the same type: %s", node.getOperands());

            return setExpressionType(node, type);
        }