using the "*" operator for Cartesian product of two collections.

[VardanKosakyan]

Currently operator overloading is not supported in extension methods. I believe it will be supported in the future. It is proposed to implement overloaded "*" operator extension for IEnumerable<T>, which will realize Cartesian product of two collections. Result of Cartesian product of two collections IEnumerable<T1> and IEnumerable<T2> will be collection of tuples IEnumerable<(T1,T2)>.
It will have more beautiful and readable syntax.

example

var col1 = new List<string> { "one", "two", "three"};
var col2 = new List<int> { 1, 2, 3, 4 };

//proposed syntax
foreach( (text, number)  in col1 * col2)
{
        Console.Write(" number {number} text {text} ";
}

//alternative
foreach( (text, number)  in col1.SelectMany( col2, (t, n) => (t, n) ))
{
        Console.Write(" number {number} text {text} ";
}

//or
foreach( text in col1)
{
       foreach( number in col2)
       {
                  Console.Write(" number {number} text {text} ";
       }
}

[HaloFour]

IMO this is a better use case for an extension method that makes it clear that the result is a Cartesian product. Different people will have different expectations as to what multiplying two collections should mean.