diff --git a/src/create-trait.js b/src/create-trait.js
index 49f952a..28ed9ad 100644
--- a/src/create-trait.js
+++ b/src/create-trait.js
@@ -12,14 +12,13 @@ const nullMissingFields = require("./util/null-missing-fields");
 
 module.exports = function createTrait(name, schema, options = {}) {
 	let schemaDescriptors = mapObj(schema, (key, rule) => {
-		return generateDescriptor(rule, key, true, options._registry);
+		return generateDescriptor(rule, key, true);
 	});
 
 	let schemaKeys = getSchemaKeys(schema);
 
 	return typeRules._createTypeRule({
 		_isTrait: true,
-		_registry: options._registry,
 		_name: name,
 		applyImplementation: function (implementation) {
 			/* FIXME: Verify that there are no extraneous keys or unspecified values */
@@ -44,9 +43,9 @@ module.exports = function createTrait(name, schema, options = {}) {
 
 			let implementationDescriptors = mapObj(implementation, (key, value) => {
 				if (value != null && value._isSlotRule === true) {
-					return generateDescriptor(schema[key], key, true, options._registry);
+					return generateDescriptor(schema[key], key, true);
 				} else {
-					return generateDescriptor(value, key, false, options._registry);
+					return generateDescriptor(value, key, false);
 				}
 			});
 
diff --git a/src/create-type.js b/src/create-type.js
index 4346c48..94a6870 100644
--- a/src/create-type.js
+++ b/src/create-type.js
@@ -9,17 +9,16 @@ const generateValidator = require("./generate-validator");
 const getSchemaKeys = require("./util/get-schema-keys");
 const nullMissingFields = require("./util/null-missing-fields");
 
-module.exports = function createType(name, schema, options = {}) {
+module.exports = function createType(name, schema) {
 	if (schema._isTypeRule === true) {
 		return typeRules._createTypeRule({
 			_typeName: name,
 			_isTypeAlias: true,
-			_alias: schema,
-			_registry: options._registry
+			_alias: schema
 		});
 	} else {
 		let propertyDescriptors = mapObj(schema, (key, rule) => {
-			return generateDescriptor(rule, key, false, options._registry);
+			return generateDescriptor(rule, key, false);
 		});
 
 		let protoProperties = {
@@ -56,7 +55,6 @@ module.exports = function createType(name, schema, options = {}) {
 
 		proto._type = factory;
 
-		factory._registry = options._registry;
 		factory._schemaKeys = schemaKeys;
 		factory._isCustomType = true;
 		factory._name = name;
diff --git a/src/generate-descriptor.js b/src/generate-descriptor.js
index 25cdc57..d70b908 100644
--- a/src/generate-descriptor.js
+++ b/src/generate-descriptor.js
@@ -4,9 +4,9 @@ const generateValidator = require("./generate-validator");
 const guardedSet = require("./guarded-collections/set");
 const guardedMap = require("./guarded-collections/map");
 
-module.exports = function generateDescriptor(rule, key, allowSlot = false, registry) {
+module.exports = function generateDescriptor(rule, key, allowSlot = false) {
 	if (rule._isTypeRule === true) {
-		let validator = generateValidator(rule, key, registry);
+		let validator = generateValidator(rule, key);
 
 		if (rule._collectionType != null) {
 			let guardedCollectionFactory;
@@ -19,8 +19,8 @@ module.exports = function generateDescriptor(rule, key, allowSlot = false, regis
 				throw new Error(`Unknown collection type: ${rule._collectionType}`);
 			}
 
-			let valueGuard = generateValidator(rule._itemType, undefined, registry);
-			let keyGuard = (rule._keyType != null) ? generateValidator(rule._keyType, undefined, registry) : null;
+			let valueGuard = generateValidator(rule._itemType);
+			let keyGuard = (rule._keyType != null) ? generateValidator(rule._keyType) : null;
 
 			return [key, {
 				enumerable: true,
diff --git a/src/generate-validator.js b/src/generate-validator.js
index 38f27b2..9243dab 100644
--- a/src/generate-validator.js
+++ b/src/generate-validator.js
@@ -12,7 +12,7 @@ const createUndefinedValidator = require("./validator-functions/undefined");
 const getValueType = require("./util/get-value-type");
 const errors = require("./errors");
 
-module.exports = function generateValidator(rule, name = "<unknown>", registry) {
+module.exports = function generateValidator(rule, name = "<unknown>") {
 	let baseRule;
 
 	if (rule._baseType != null) {
@@ -37,7 +37,7 @@ module.exports = function generateValidator(rule, name = "<unknown>", registry)
 		baseRule = () => true; /* FIXME */
 	} else if (rule._modifierType != null) {
 		if (rule._modifierType === "either") {
-			let validators = rule._types.map((type) => generateValidator(type, undefined, registry));
+			let validators = rule._types.map((type) => generateValidator(type));
 
 			baseRule = function (value) {
 				let matched = false;
@@ -60,7 +60,7 @@ module.exports = function generateValidator(rule, name = "<unknown>", registry)
 			throw new Error(`Unrecognized modifier: ${rule._modifierType}`);
 		}
 	} else if (rule._isTypeAlias === true) {
-		baseRule = generateValidator(rule._alias, name, registry);
+		baseRule = generateValidator(rule._alias, name);
 	} else if (rule._isCustomType === true) {
 		let validator = rule._validator;
 
@@ -77,7 +77,7 @@ module.exports = function generateValidator(rule, name = "<unknown>", registry)
 
 		baseRule = function (value) {
 			/* FIXME: Better error when the type is unknown */
-			let actualType = registry._types.get(rule._name);
+			let actualType = rule._registry._types.get(rule._name);
 
 			if (actualType._isCustomType) {
 				if (actualType._validator.call(this, value) === true) {
@@ -87,7 +87,7 @@ module.exports = function generateValidator(rule, name = "<unknown>", registry)
 				}
 			} else {
 				if (aliasValidator == null) {
-					aliasValidator = generateValidator(actualType._alias, name, registry);
+					aliasValidator = generateValidator(actualType._alias, name);
 				}
 
 				let validatorResult = aliasValidator.call(this, value);
@@ -110,21 +110,17 @@ module.exports = function generateValidator(rule, name = "<unknown>", registry)
 			}
 		};
 	} else if (rule._isRegistryTrait === true) {
-		if (registry == null) {
-			throw new Error("Registry-based type rules can only be used within the context of a type registry");
-		} else {
-			baseRule = function (value) {
-				/* TODO: The below approach requires that traits be defined before the types that use them, and disallows trait registry references in `.implements` calls, due to _implementedTraits always needing to contain actual trait definitions; in the future, a better approach needs to be found for this such that trait registry references can be used everywhere. */
-				let actualRule = registry._traits.get(rule._name);
+		baseRule = function (value) {
+			/* TODO: The below approach requires that traits be defined before the types that use them, and disallows trait registry references in `.implements` calls, due to _implementedTraits always needing to contain actual trait definitions; in the future, a better approach needs to be found for this such that trait registry references can be used everywhere. */
+			let actualRule = rule._registry._traits.get(rule._name);
 
-				/* FIXME: Better error when the trait is unknown */
-				if (value._type != null && value._type._implementedTraits != null && value._type._implementedTraits.has(actualRule)) {
-					return true;
-				} else {
-					return new errors.ValidationError(`Expected object of a type with the ${rule._name} trait, got ${getValueType(value)} instead`);
-				}
-			};
-		}
+			/* FIXME: Better error when the trait is unknown */
+			if (value._type != null && value._type._implementedTraits != null && value._type._implementedTraits.has(actualRule)) {
+				return true;
+			} else {
+				return new errors.ValidationError(`Expected object of a type with the ${rule._name} trait, got ${getValueType(value)} instead`);
+			}
+		};
 	} else if (rule._isSelfRule === true) {
 		baseRule = function (value) {
 			if (value instanceof this._type) {
@@ -195,7 +191,7 @@ module.exports = function generateValidator(rule, name = "<unknown>", registry)
 					});
 				}
 			} else {
-				/* FIXME: Possibly special-case (for better performance) if the only extra rule is a 'default value' rule? This would avoid a `for` loop in the case where a value is explicitly specified. */
+				/* TODO: Possibly special-case (for better performance) if the only extra rule is a 'default value' rule? This would avoid a `for` loop in the case where a value is explicitly specified. */
 				for (let rule of rules) {
 					let result = rule.call(this, value);
 
diff --git a/src/guard-function.js b/src/guard-function.js
index 3a8fb09..9580db5 100644
--- a/src/guard-function.js
+++ b/src/guard-function.js
@@ -2,12 +2,12 @@
 
 const generateValidator = require("./generate-validator");
 
-module.exports = function guardFunction(args, returnType, func, _registry) {
+module.exports = function guardFunction(args, returnType, func) {
 	let rules = args.map((arg) => {
-		return generateValidator(arg, undefined, _registry);
+		return generateValidator(arg);
 	});
 
-	let returnValueValidator = generateValidator(returnType, undefined, _registry);
+	let returnValueValidator = generateValidator(returnType);
 
 	let guardedFunction = function (...params) {
 		let paramsWithDefaults = new Array(params.length);
diff --git a/src/registry.js b/src/registry.js
index e7c69ea..4b24935 100644
--- a/src/registry.js
+++ b/src/registry.js
@@ -11,11 +11,7 @@ module.exports = function createRegistry() {
 		_traits: new Map(),
 		createType: function (name, schema, options = {}) {
 			if (!this._types.has(name)) {
-				let combinedOptions = Object.assign({
-					_registry: this
-				}, options);
-
-				let type = moduleAPI.createType(name, schema, combinedOptions);
+				let type = moduleAPI.createType(name, schema, options);
 				this._types.set(name, type);
 				return type;
 			} else {
@@ -24,30 +20,25 @@ module.exports = function createRegistry() {
 		},
 		createTrait: function (name, schema, options = {}) {
 			if (!this._traits.has(name)) {
-				let combinedOptions = Object.assign({
-					_registry: this
-				}, options);
-
-				let trait = moduleAPI.createTrait(name, schema, combinedOptions);
+				let trait = moduleAPI.createTrait(name, schema, options);
 				this._traits.set(name, trait);
 				return trait;
 			} else {
 				throw new Error(`A trait named ${name} already exists in this registry`);
 			}
 		},
-		guardFunction: function (args, returnType, func) {
-			return moduleAPI.guardFunction(args, returnType, func, this);
-		},
 		type: function (typeName) {
 			return typeRules._createTypeRule({
 				_isCustomRegistryType: true,
-				_name: typeName
+				_name: typeName,
+				_registry: this
 			});
 		},
 		trait: function (traitName) {
 			return typeRules._createTypeRule({
 				_isRegistryTrait: true,
-				_name: traitName
+				_name: traitName,
+				_registry: this
 			});
 		},
 		createRegistry: undefined
diff --git a/test/models.js b/test/models.js
index 88a3490..80b1f97 100644
--- a/test/models.js
+++ b/test/models.js
@@ -5,7 +5,6 @@ const expect = require("chai").expect;
 const dm = require("../src");
 
 /* FIXME: Disallow null/nothing/undefined in model definitions, as they make no semantic sense? But allow them for eg. function guards. */
-/* FIXME: Registry */
 /* FIXME: Test passing an already-guarded collection into a guarded collection factory - either stand-alone or in the context of a model? */
 let Identity = dm.createType("Identity", {
 	label: dm.string(),