diff --git a/src/Plugin/Promise/GeocoderFulfilledPromise.php b/src/Plugin/Promise/GeocoderFulfilledPromise.php
index a68aaef48..456f66a62 100644
--- a/src/Plugin/Promise/GeocoderFulfilledPromise.php
+++ b/src/Plugin/Promise/GeocoderFulfilledPromise.php
@@ -36,7 +36,7 @@ public function __construct(Collection $collection)
     /**
      * {@inheritdoc}
      */
-    public function then(callable $onFulfilled = null, callable $onRejected = null)
+    public function then(callable $onFulfilled = null, callable $onRejected = null): Promise
     {
         if (null === $onFulfilled) {
             return $this;
@@ -52,13 +52,15 @@ public function then(callable $onFulfilled = null, callable $onRejected = null)
     /**
      * {@inheritdoc}
      */
-    public function getState()
+    public function getState(): string
     {
         return Promise::FULFILLED;
     }
 
     /**
      * {@inheritdoc}
+     *
+     * @return mixed
      */
     public function wait($unwrap = true)
     {
diff --git a/src/Plugin/Promise/GeocoderRejectedPromise.php b/src/Plugin/Promise/GeocoderRejectedPromise.php
index 40cd4f220..55c2369a1 100644
--- a/src/Plugin/Promise/GeocoderRejectedPromise.php
+++ b/src/Plugin/Promise/GeocoderRejectedPromise.php
@@ -35,7 +35,7 @@ public function __construct(Exception $exception)
     /**
      * {@inheritdoc}
      */
-    public function then(callable $onFulfilled = null, callable $onRejected = null)
+    public function then(callable $onFulfilled = null, callable $onRejected = null): Promise
     {
         if (null === $onRejected) {
             return $this;
@@ -51,13 +51,15 @@ public function then(callable $onFulfilled = null, callable $onRejected = null)
     /**
      * {@inheritdoc}
      */
-    public function getState()
+    public function getState(): string
     {
         return Promise::REJECTED;
     }
 
     /**
      * {@inheritdoc}
+     *
+     * @return mixed
      */
     public function wait($unwrap = true)
     {