// CS0278: `Testing.IMixedEnumerable' contains ambiguous implementation of `enumerable' pattern. Method `System.Collections.IEnumerable.GetEnumerator()' is ambiguous with method `Testing.ICustomEnumerable.GetEnumerator()' // Line: 28 // Compiler options: -warnaserror -warn:2 using System; using System.Collections; namespace Testing { interface ICustomEnumerable { IEnumerator GetEnumerator(); } interface IMixedEnumerable : IEnumerable, ICustomEnumerable {} class TestCollection : IMixedEnumerable { IEnumerator IEnumerable.GetEnumerator() { return null; } IEnumerator ICustomEnumerable.GetEnumerator() { return null; } } class Test { public static void Main(string[] args) { IMixedEnumerable c = new TestCollection(); foreach(object o in c) {} } } }