ReSharper accepts this program, the compiler does not.

This could be the same underlying bug as RSRP-70646, but I have no way to be sure.

using System.Collections.Generic;

namespace ConsoleApplication11 {
  public class MainClass {
    public static void Main() {
      var temp2=new[] {"hello"}.Test<string, MainClass>();
    }
  }

  public static class ExtensionMethods {
    public static IList<U> Test<T, U>(this IList<U> list) {
      return list;
    }
  }
}

Issue was closed