diff --git a/src/enum.js b/src/enum.js
index 9eaec4ea5..59a6ef7f0 100644
--- a/src/enum.js
+++ b/src/enum.js
@@ -5,7 +5,8 @@ module.exports = Enum;
 var ReflectionObject = require("./object");
 ((Enum.prototype = Object.create(ReflectionObject.prototype)).constructor = Enum).className = "Enum";
 
-var util = require("./util");
+var Namespace = require("./namespace"),
+    util = require("./util");
 
 /**
  * Constructs a new enum instance.
@@ -84,7 +85,7 @@ Enum.prototype.toJSON = function toJSON() {
     return util.toObject([
         "options"  , this.options,
         "values"   , this.values,
-        "reserved" , this.reserved
+        "reserved" , this.reserved && this.reserved.length ? this.reserved : undefined
     ]);
 };
 
@@ -97,7 +98,7 @@ Enum.prototype.toJSON = function toJSON() {
  * @throws {TypeError} If arguments are invalid
  * @throws {Error} If there is already a value with this name or id
  */
-Enum.prototype.add = function(name, id, comment) {
+Enum.prototype.add = function add(name, id, comment) {
     // utilized by the parser but not by .fromJSON
 
     if (!util.isString(name))
@@ -107,11 +108,17 @@ Enum.prototype.add = function(name, id, comment) {
         throw TypeError("id must be an integer");
 
     if (this.values[name] !== undefined)
-        throw Error("duplicate name");
+        throw Error("duplicate name '" + name + "' in " + this);
+
+    if (this.isReservedId(id))
+        throw Error("id " + id + " is reserved in " + this);
+
+    if (this.isReservedName(name))
+        throw Error("name '" + name + "' is reserved in " + this);
 
     if (this.valuesById[id] !== undefined) {
         if (!(this.options && this.options.allow_alias))
-            throw Error("duplicate id");
+            throw Error("duplicate id " + id + " in " + this);
         this.values[name] = id;
     } else
         this.valuesById[this.values[name] = id] = name;
@@ -127,14 +134,14 @@ Enum.prototype.add = function(name, id, comment) {
  * @throws {TypeError} If arguments are invalid
  * @throws {Error} If `name` is not a name of this enum
  */
-Enum.prototype.remove = function(name) {
+Enum.prototype.remove = function remove(name) {
 
     if (!util.isString(name))
         throw TypeError("name must be a string");
 
     var val = this.values[name];
-    if (val === undefined)
-        throw Error("name does not exist");
+    if (val == null)
+        throw Error("name '" + name + "' does not exist in " + this);
 
     delete this.valuesById[val];
     delete this.values[name];
@@ -142,3 +149,21 @@ Enum.prototype.remove = function(name) {
 
     return this;
 };
+
+/**
+ * Tests if the specified id is reserved.
+ * @param {number} id Id to test
+ * @returns {boolean} `true` if reserved, otherwise `false`
+ */
+Enum.prototype.isReservedId = function isReservedId(id) {
+    return Namespace.isReservedId(this.reserved, id);
+};
+
+/**
+ * Tests if the specified name is reserved.
+ * @param {string} name Name to test
+ * @returns {boolean} `true` if reserved, otherwise `false`
+ */
+Enum.prototype.isReservedName = function isReservedName(name) {
+    return Namespace.isReservedName(this.reserved, name);
+};
diff --git a/src/namespace.js b/src/namespace.js
index 7d6bd6d1c..ff96aada1 100644
--- a/src/namespace.js
+++ b/src/namespace.js
@@ -52,6 +52,34 @@ function arrayToJSON(array) {
 
 Namespace.arrayToJSON = arrayToJSON;
 
+/**
+ * Tests if the specified id is reserved.
+ * @param {Array.<number[]|string>|undefined} reserved Array of reserved ranges and names
+ * @param {number} id Id to test
+ * @returns {boolean} `true` if reserved, otherwise `false`
+ */
+Namespace.isReservedId = function isReservedId(reserved, id) {
+    if (reserved)
+        for (var i = 0; i < reserved.length; ++i)
+            if (typeof reserved[i] !== "string" && reserved[i][0] <= id && reserved[i][1] >= id)
+                return true;
+    return false;
+};
+
+/**
+ * Tests if the specified name is reserved.
+ * @param {Array.<number[]|string>|undefined} reserved Array of reserved ranges and names
+ * @param {string} name Name to test
+ * @returns {boolean} `true` if reserved, otherwise `false`
+ */
+Namespace.isReservedName = function isReservedName(reserved, name) {
+    if (reserved)
+        for (var i = 0; i < reserved.length; ++i)
+            if (reserved[i] === name)
+                return true;
+    return false;
+};
+
 /**
  * Not an actual constructor. Use {@link Namespace} instead.
  * @classdesc Base class of all reflection objects containing nested objects. This is not an actual class but here for the sake of having consistent type definitions.
diff --git a/src/type.js b/src/type.js
index cc61a03ad..e22b65113 100644
--- a/src/type.js
+++ b/src/type.js
@@ -395,11 +395,7 @@ Type.prototype.remove = function remove(object) {
  * @returns {boolean} `true` if reserved, otherwise `false`
  */
 Type.prototype.isReservedId = function isReservedId(id) {
-    if (this.reserved)
-        for (var i = 0; i < this.reserved.length; ++i)
-            if (typeof this.reserved[i] !== "string" && this.reserved[i][0] <= id && this.reserved[i][1] >= id)
-                return true;
-    return false;
+    return Namespace.isReservedId(this.reserved, id);
 };
 
 /**
@@ -408,11 +404,7 @@ Type.prototype.isReservedId = function isReservedId(id) {
  * @returns {boolean} `true` if reserved, otherwise `false`
  */
 Type.prototype.isReservedName = function isReservedName(name) {
-    if (this.reserved)
-        for (var i = 0; i < this.reserved.length; ++i)
-            if (this.reserved[i] === name)
-                return true;
-    return false;
+    return Namespace.isReservedName(this.reserved, name);
 };
 
 /**