Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

mcs/tests/test-495.cs

@@ -0,0 +1,28 @@
+// This code must be compilable without any warning
+// Compiler options: -warnaserror -warn:4
+
+using System;
+
+namespace plj
+{
+	public abstract class aClass
+	{
+		public static implicit operator aClass(fromClass o)
+		{ 
+			return null;
+		}
+	}
+	
+	public class realClass1 : aClass
+	{
+		public static implicit operator realClass1(fromClass o)
+		{
+			return null;
+		}
+	}
+	
+	public class fromClass
+	{
+		public static void Main () {}
+	}
+}