diff --git a/core/lib/Drupal/Core/Plugin/Context/ContextDefinition.php b/core/lib/Drupal/Core/Plugin/Context/ContextDefinition.php
index 5c0e894abf..8bb52772ec 100644
--- a/core/lib/Drupal/Core/Plugin/Context/ContextDefinition.php
+++ b/core/lib/Drupal/Core/Plugin/Context/ContextDefinition.php
@@ -108,6 +108,8 @@ public function __construct($data_type = 'any', $label = NULL, $required = TRUE,
     $this->isMultiple = $multiple;
     $this->description = $description;
     $this->defaultValue = $default_value;
+
+    assert(strpos($data_type, 'entity:') !== 0 || $this instanceof EntityContextDefinition);
   }
 
   /**
diff --git a/core/tests/Drupal/KernelTests/Core/Plugin/ContextDefinitionTest.php b/core/tests/Drupal/KernelTests/Core/Plugin/ContextDefinitionTest.php
index 842f76b456..c7fd4e1f6f 100644
--- a/core/tests/Drupal/KernelTests/Core/Plugin/ContextDefinitionTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Plugin/ContextDefinitionTest.php
@@ -34,4 +34,15 @@ public function testIsSatisfiedBy() {
     $this->assertTrue($requirement->isSatisfiedBy($context));
   }
 
+
+  /**
+   * @covers ::__construct
+   */
+  public function testEntityContextDefinitionAssert() {
+    $this->expectException(\AssertionError::class);
+    $this->expectExceptionMessage('assert(strpos($data_type, \'entity:\') !== 0 || $this instanceof EntityContextDefinition)');
+    new ContextDefinition('entity:entity_test');
+  }
+
+
 }