How to make IEqualityComparer<Type> for generic types

Question

I want an IEqualityComparer<Type> that returns true if and only if two generic types are the same ignoring generic parameters. So comparer.Equals(typeof(List<A>), typeof(List<B>)) should return true.

I am doing a comparison by Name:

public class GenericTypeEqualityComparer : IEqualityComparer<Type>
{
    public bool Equals(Type x, Type y)
    {
        return x.Name == y.Name;
    }

    public int GetHashCode(Type obj)
    {
        return obj.Name.GetHashCode();
    }
}

There are some false positive cases (namespace issues, etc.). I don't know what else to do.

Answer 1

Here is a check that takes the generic into account. It would throw a NRE if x or y were null though so if you want a more robust check add a null check too.

public bool Equals(Type x, Type y)
{
    var a = x.IsGenericType ? x.GetGenericTypeDefinition() : x;
    var b = y.IsGenericType ? y.GetGenericTypeDefinition() : y;
    return a == b;
}