diff --git a/core/lib/Drupal/Core/Entity/EntityResolverManager.php b/core/lib/Drupal/Core/Entity/EntityResolverManager.php
index 79e62d1c3ae9bc1459a72ca1077d7cc35c9c25d3..847a480e4c9e48f494a0ca89851f69da30e1b3a0 100644
--- a/core/lib/Drupal/Core/Entity/EntityResolverManager.php
+++ b/core/lib/Drupal/Core/Entity/EntityResolverManager.php
@@ -166,7 +166,10 @@ protected function setParametersFromEntityInformation(Route $route) {
       list($entity_type) = explode('.', $entity_form, 2);
     }
 
-    if (isset($entity_type) && isset($this->getEntityTypes()[$entity_type])) {
+    // Do not add parameter information if the route does not declare a
+    // parameter in the first place. This is the case for add forms, for
+    // example.
+    if (isset($entity_type) && isset($this->getEntityTypes()[$entity_type]) && (strpos($route->getPath(), '{' . $entity_type . '}') !== FALSE)) {
       $parameter_definitions = $route->getOption('parameters') ?: array();
 
       // First try to figure out whether there is already a parameter upcasting
diff --git a/core/tests/Drupal/Tests/Core/Entity/EntityResolverManagerTest.php b/core/tests/Drupal/Tests/Core/Entity/EntityResolverManagerTest.php
index bacab58af1289b12ce8ad48a1ab045bc1d7109e2..6e164708b94d11b12f5dd5a59be980a09c2f6d89 100644
--- a/core/tests/Drupal/Tests/Core/Entity/EntityResolverManagerTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/EntityResolverManagerTest.php
@@ -416,6 +416,27 @@ public function testSetRouteOptionsWithEntityFormRouteAndArgument() {
     $this->assertEquals($expect, $parameters);
   }
 
+  /**
+   * Tests setRouteOptions() with an _entity_form route for an add form.
+   *
+   * @covers ::setRouteOptions
+   * @covers ::getControllerClass
+   * @covers ::getEntityTypes
+   * @covers ::setParametersFromReflection
+   * @covers ::setParametersFromEntityInformation
+   */
+  public function testSetRouteOptionsWithEntityAddFormRoute() {
+    $this->setupEntityTypes();
+    $route = new Route('/example/add', array(
+      '_entity_form' => 'entity_test.add',
+    ));
+
+    $defaults = $route->getDefaults();
+    $this->entityResolverManager->setRouteOptions($route);
+    $this->assertEquals($defaults, $route->getDefaults());
+    $this->assertFalse($route->hasOption('parameters'));
+  }
+
   /**
    * Creates the entity manager mock returning entity type objects.
    */