Better way to declare generic parameters on class

I'm writing a FluentValidation custom validator to validate that two read only collections have the same number of elements.

I'm using VS2022 and FluentValidation v11.5.2.

I current have the following:

public class CollectionSizesMatchValidator<T, TProperty, TElement> : PropertyValidator<T, TProperty>
	where TProperty : IReadOnlyCollection<TElement>

but I'm getting a CA1005 message: Avoid excessive parameters on generic types.

I thought this might be a better solution but it doesn't compile

public class CollectionSizesMatchValidator<T, IReadOnlyCollection<TElement>> : PropertyValidator<T, IReadOnlyCollection<TElement>>

I don't like the warning generated by the compiler, so I'd like to reduce the number of generic types. I thought I could use ICollection, but IReadOnlyCollection<T> doesn't "inherit" from ICollection

When I use the validator I have to supply all the types.

Is there a better solution than the one I currently have?

In your second attempt you need to specify TElement as generic parameter, not IReadOnlyCollection<...> and then use it for PropertyValidator<T, IReadOnlyCollection<TElement>>:

public class CollectionSizesMatchValidator<T, TElement> : PropertyValidator<T, IReadOnlyCollection<TElement>>
{
    public override bool IsValid(ValidationContext<T> context, IReadOnlyCollection<TElement> value)
    {
        throw new NotImplementedException();
    }

    public override string Name { get; }
}

Or just disable the warning as explained in the docs.