Question

How can I check whether a certain type implements a certain operator?

struct CustomOperatorsClass
{
    public int Value { get; private set; }


    public CustomOperatorsClass( int value )
        : this()
    {
        Value = value;
    }

    static public CustomOperatorsClass operator +(
        CustomOperatorsClass a, CustomOperatorsClass b )
    {
        return new CustomOperatorsClass( a.Value + b.Value );
    }
}

Following two checks should return true:

typeof( CustomOperatorsClass ).HasOperator( Operator.Addition )
typeof( int ).HasOperator( Operator.Addition )

Answer 1

There is a quick and dirty way to find out, and it works for both built-in and custom types. Its major drawback is that it relies on exceptions in a normal flow, but it gets the job done.

 static bool HasAdd<T>() {
    var c = Expression.Constant(default(T), typeof(T));
    try {
        Expression.Add(c, c); // Throws an exception if + is not defined
        return true;
    } catch {
        return false;
    }
}