Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

mcs/errors/cs0457-3.cs

@@ -0,0 +1,32 @@
+// CS0457: Ambiguous user defined operators `D.implicit operator A(D)' and `C.implicit operator B(C)' when converting from `D' to `B'
+// Line: 30
+
+class A
+{
+}
+
+class B : A
+{
+}
+
+class C
+{
+	public static implicit operator B (C s)
+	{
+		return new B ();
+	}
+}
+
+class D : C
+{
+	public static implicit operator A (D s)
+	{
+		return new B ();
+	}
+
+	public static void Main ()
+	{
+		D d = new D ();
+		B b2 = (B) d;
+	}
+}