diff --git a/src/values/options.js b/src/values/options.js
index dcf2c02..1f79341 100644
--- a/src/values/options.js
+++ b/src/values/options.js
@@ -65,11 +65,7 @@ class Builder {
 				parent.add(parser, v => v[0]);
 			}
 
-			parent.mapResults(v => ({
-				option: v.intent,
-				values: v.values,
-				expression: v.expression
-			}));
+			parent.mapResults(v => new Option(v.intent, v.values, v.expression));
 
 			const repeating = language.repeating(parent.toMatcher())
 				.onlyBest()
@@ -85,3 +81,22 @@ class Builder {
 export default function(options={}) {
 	return new Builder(options);
 }
+
+/**
+ * Custom option value to hide enumeration for equality checks.
+ */
+class Option {
+
+	constructor(option, values, expression) {
+		this.option = option;
+		this.values = values;
+
+		Object.defineProperty(this, 'expression', {
+			enumerable: false,
+			writable: true
+		});
+
+		this.expression = expression;
+	}
+
+}
diff --git a/test/value-options.test.js b/test/value-options.test.js
index 6677e8d..688c656 100644
--- a/test/value-options.test.js
+++ b/test/value-options.test.js
@@ -21,13 +21,14 @@ describe('Value: Options', function() {
 					{
 						option: 'deadline',
 						values: {},
-						expression: [
-							{
-								type: 'text',
-								value: 'with deadline',
-								source: { start: 0, end: 13 }
-							}
-						]
+					}
+				]);
+
+				expect(v[0].expression).to.deep.equal([
+					{
+						type: 'text',
+						value: 'with deadline',
+						source: { start: 0, end: 13 }
 					}
 				]);
 			})
@@ -39,13 +40,14 @@ describe('Value: Options', function() {
 					{
 						option: 'deadline',
 						values: {},
-						expression: [
-							{
-								type: 'text',
-								value: 'with deadline',
-								source: { start: 0, end: 13 }
-							}
-						]
+					}
+				]);
+
+				expect(v[0].expression).to.deep.equal([
+					{
+						type: 'text',
+						value: 'with deadline',
+						source: { start: 0, end: 13 }
 					}
 				]);
 			})
@@ -57,13 +59,14 @@ describe('Value: Options', function() {
 					{
 						option: 'deadline',
 						values: {},
-						expression: [
-							{
-								type: 'text',
-								value: 'with deadline',
-								source: { start: 0, end: 4 }
-							}
-						]
+					}
+				]);
+
+				expect(v[0].expression).to.deep.equal([
+					{
+						type: 'text',
+						value: 'with deadline',
+						source: { start: 0, end: 4 }
 					}
 				]);
 			})
@@ -75,13 +78,14 @@ describe('Value: Options', function() {
 					{
 						option: 'deadline',
 						values: {},
-						expression: [
-							{
-								type: 'text',
-								value: 'with deadline',
-								source: { start: 0, end: 6 }
-							}
-						]
+					}
+				]);
+
+				expect(v[0].expression).to.deep.equal([
+					{
+						type: 'text',
+						value: 'with deadline',
+						source: { start: 0, end: 6 }
 					}
 				]);
 			})
@@ -93,24 +97,26 @@ describe('Value: Options', function() {
 					{
 						option: 'deadline',
 						values: {},
-						expression: [
-							{
-								type: 'text',
-								value: 'with deadline',
-								source: { start: 0, end: 13 }
-							}
-						]
 					},
 					{
 						option: 'deadline',
-						values: {},
-						expression: [
-							{
-								type: 'text',
-								value: 'with deadline',
-								source: { start: 18, end: 20 }
-							}
-						]
+						values: {}
+					}
+				]);
+
+				expect(v[0].expression).to.deep.equal([
+					{
+						type: 'text',
+						value: 'with deadline',
+						source: { start: 0, end: 13 }
+					}
+				]);
+
+				expect(v[1].expression).to.deep.equal([
+					{
+						type: 'text',
+						value: 'with deadline',
+						source: { start: 18, end: 20 }
 					}
 				]);
 			})