// CS0151: A switch expression of type `S1?' cannot be converted to an integral type, bool, char, string, enum or nullable type // Line: 24 using System; struct S1 { public static implicit operator int? (S1? s) { throw new ApplicationException (); } public static implicit operator int (S1? s) { throw new ApplicationException (); } } class C { public static int Main () { S1? s1 = new S1 (); switch (s1) { default: return 1; } } }