ambiguous between in `Add(TValue)` and `Add(params IEnumerable<TValue>)`

[zms9110750]

Version Used:
Visual Studio Community 2022 - 17.14.16

Steps to Reproduce:

.NET Lab

1. Define the following types:

   interface ITree<TV, TNode> where TNode : ITree<TV, TNode>;
   class Tree<T> : ITree<T, Tree<T>>;

2. Create an extension method with two overloads:

   static class P
   {
       extension<TV, TN>(ITree<TV, TN> node) where TN : ITree<TV, TN>
       {
           public void Add(TV value) { }
           public void Add(params TV[] values) { }
       }
   }

3. Try to call Add with a single argument:

   Tree<int> b = new Tree<int>();
   b.Add(1); // CS0121: Ambiguous call between 'Add(TV)' and 'Add(params TV[])'

Expected Behavior:
The compiler should resolve b.Add(1) to the non-params overload (Add(TV)), since it has a fixed number of arguments.

Actual Behavior:
Compiler error CS0121 occurs, indicating ambiguity between Add(TV) and Add(params TV[]).

Diagnostic Id:
CS0121 (The call is ambiguous between the following methods or properties)

[RikkiGibson]

Added .NET Lab link. @jcouv can you comment whether this behavior is expected?

[jcouv]

There's no error with corresponding classic extension methods, so definitely a bug. I'll investigate