Derived class using the wrong method
c#, inheritance, overloading
Solution
A member lookup of a name N in a type T is processed as follows:
First, the set of all accessible members named N declared in T and the base types of T is constructed. Declarations that include an override modifier are excluded from the set. If no members named N exist and are accessible, then the lookup produces no match, and the following steps are not evaluated.
Thus when you use variable of Child type
Child d = new Child();
int i = 100;
d.AddToTotal(i);
method `public override void AddToTotal(int number)` is excluded from set, and we have only one method with name N left. Int is converted implicitly to double, so no errors occured.
Problem
I have simplified my code to this ``` internal class Program { private static void Main(string[] args) { Child d = new Child(); int i = 100; d.AddToTotal(i); Console.ReadKey(); } private class Parent { public virtual void AddToTotal(int x) { Console.WriteLine("Parent.AddToTotal(int)"); } } private class Child : Parent { public override void AddToTotal(int number) { Console.WriteLine("Child.AddToTotal(int)"); } public void AddToTotal(double currency) { Console.WriteLine("Child.AddToTotal(double)"); } } } ``` The issue is that this calls ``` public void AddToTotal(double currency) ``` although I am calling it with an int and it should be using ``` public override void AddToTotal(int number) ``` Using the parent returns the expected result. ``` Parent d = new Child(); int i = 100; d.AddToTotal(i); ``` Update: Thanks to @Jan and @azyberezovsky for pointing me to the specification. I have added a virtual empty method to the base class to get around this for now.