presto-main/src/main/java/io/prestosql/sql/analyzer/ExpressionAnalyzer.java/ExpressionAnalyzer/visitDoubleLiteral
class ExpressionAnalyzer:        @Override
        protected Type visitDoubleLiteral(DoubleLiteral node, StackableAstVisitorContext<Context> context)
        {
            return setExpressionType(node, DOUBLE);
        }