Imported Upstream version 5.16.0.112

Former-commit-id: 6cc2610f66eef3edea492b48d5312acef686f417

mcs/class/corlib/ReferenceSources/RuntimeType.cs

@@ -810,5 +810,20 @@ namespace System
 				return false;
 			}
 		}
+
+		[System.Runtime.InteropServices.ComVisible(true)]
+		[Pure]
+		public override bool IsSubclassOf(Type type)
+		{
+			if ((object)type == null)
+				throw new ArgumentNullException("type");
+			Contract.EndContractBlock();
+			RuntimeType rtType = type as RuntimeType;
+			if (rtType == null)
+				return false;
+
+			return RuntimeTypeHandle.IsSubclassOf (this, rtType);
+		}
+
 	}
 }