diff --git a/src/util/builtinOperators.ts b/src/util/builtinOperators.ts
index d05800c..94e3414 100644
--- a/src/util/builtinOperators.ts
+++ b/src/util/builtinOperators.ts
@@ -224,11 +224,9 @@ function keyMatch4(key1: string, key2: string): boolean {
   });
 
   for (const value of m.values()) {
-    if (value.length > 1) {
-      for (let i = 1; i < values.length; i++) {
-        if (values[i] !== values[0]) {
-          return false;
-        }
+    for (let i = 1; i < value.length; i++) {
+      if (value[i] !== value[0]) {
+        return false;
       }
     }
   }
diff --git a/test/util.test.ts b/test/util.test.ts
index a7bf769..bce2f09 100644
--- a/test/util.test.ts
+++ b/test/util.test.ts
@@ -91,6 +91,13 @@ test('test keyMatch4Func', () => {
   expect(util.keyMatch4Func('/parent/123/child/456/book/123', '/parent/{id}/child/{id}/book/{id}')).toEqual(false);
   expect(util.keyMatch4Func('/parent/123/child/456/book/', '/parent/{id}/child/{id}/book/{id}')).toEqual(false);
   expect(util.keyMatch4Func('/parent/123/child/456', '/parent/{id}/child/{id}/book/{id}')).toEqual(false);
+
+  // A repeated token must not be compared with the values of other tokens.
+  expect(util.keyMatch4Func('/parent/123/child/123/book/456', '/parent/{id}/child/{id}/book/{book_id}')).toEqual(true);
+  expect(util.keyMatch4Func('/parent/123/child/456/book/789', '/parent/{id}/child/{id}/book/{book_id}')).toEqual(false);
+  expect(util.keyMatch4Func('/org/1/user/2/org/1', '/org/{org}/user/{user}/org/{org}')).toEqual(true);
+  expect(util.keyMatch4Func('/org/1/user/2/org/3', '/org/{org}/user/{user}/org/{org}')).toEqual(false);
+  expect(util.keyMatch4Func('/a/x/b/y/c/y', '/a/{p}/b/{q}/c/{q}')).toEqual(true);
 });
 
 test('test keyMatch5Func', () => {