Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

mcs/errors/cs0023-11.cs

@@ -0,0 +1,17 @@
+// CS0023: The `-' operator cannot be applied to operand of type `A'
+// Line: 16
+
+
+class A
+{
+	public static implicit operator ulong (A mask)
+	{
+		return 8;
+	}
+}
+
+class X
+{
+    static A a = null;
+    static object o = -a;
+}